Download P1237 REQUESTED INFORMATION TEST KB: FUEL PUMP DRIVER MODULE

5/15/2015
Printer Friendly View
2003 Mercury Grand Marquis 4.6L Eng GS
1Search™
P1237
REQUESTED INFORMATION
TEST KB: FUEL PUMP DRIVER MODULE
NOTE: After each service or repair procedure
has been completed, reconnect all components. Clear
DTCs and repeat QUICK TEST procedures to
ensure all EEC-V systems are working properly and
DTCs are no longer present.
Diagnostic Aids
Perform this test when instructed during QUICK TEST or if directed by other test procedures. This test is
used to diagnose the following:
Wiring Harness Circuits (B+, GND & VPWR To Fuel Pump Relay; FP, FPM, FP PWR, FP RTN &
FPDM PWR). See Fig 1-Fig 5 .
Faulty Inertia Fuel Shutoff (IFS) Switch
Faulty Fuel Pump Driver Module (FPDM)
Faulty Power Supply Relay Inside Constant Control Relay Module (CCRM)
Faulty Powertrain Control Module (PCM)
http://www2.prodemand.com/Print/Index?content=tabs&module=true&tab=true&terms=true&ymms=false&className=
1/21
5/15/2015
Printer Friendly View
Fig 1: Identifying Fuel Pump Driver Module Circuits & Connector Terminals (Aviator)
Courtesy of FORD MOTOR CO.
http://www2.prodemand.com/Print/Index?content=tabs&module=true&tab=true&terms=true&ymms=false&className=
2/21
5/15/2015
Printer Friendly View
Fig 2: Identifying Fuel Pump Driver Module Circuits & Connector Terminals (Focus, Crown Victoria,
Grand Marquis, Sable, Taurus & Town Car)
Courtesy of FORD MOTOR CO.
http://www2.prodemand.com/Print/Index?content=tabs&module=true&tab=true&terms=true&ymms=false&className=
3/21
5/15/2015
Printer Friendly View
Fig 3: Identifying Fuel Pump Driver Module Circuits & Connector Terminals (Mustang)
Courtesy of FORD MOTOR CO.
http://www2.prodemand.com/Print/Index?content=tabs&module=true&tab=true&terms=true&ymms=false&className=
4/21
5/15/2015
Printer Friendly View
Fig 4: Identifying Fuel Pump Driver Module Circuits & Connector Terminals (ZX2)
Courtesy of FORD MOTOR CO.
http://www2.prodemand.com/Print/Index?content=tabs&module=true&tab=true&terms=true&ymms=false&className=
5/21
5/15/2015
Printer Friendly View
Fig 5: Identifying Fuel Pump & Rear Electronics Module Circuits & Connector Terminals (LS &
Thunderbird)
Courtesy of FORD MOTOR CO.
Testing
NOTE: For additional testing information,
see DIAGNOSTIC AIDS .
NOTE: DTC P1233 and P1234 are identical,
except DTC P1234 will not illuminate Malfunction
Indicator Lamp (MIL). On LS models, these
DTCs indicate PCM is not receiving fuel level
information on SCP network from Rear
Electronics Module (REM). See MODULE
COMMUNICATIONS NETWORK - LS article in
ACCESSORIES & EQUIPMENT for complete
DTC listing and test procedures.
1) For KOEO, KOER & Continuous Memory DTCs P1233 & P1234: Check For KOEO DTC P1233
Or P1234These DTCs indicate PCM has stopped receiving duty cycle signal from Fuel Pump
Driver Module (FPDM). Possible causes are:
Inertia Fuel Shutoff (IFS) Switch Needs To Be Reset
Open FPDM Ground Circuit
http://www2.prodemand.com/Print/Index?content=tabs&module=true&tab=true&terms=true&ymms=false&className=
6/21
5/15/2015
Printer Friendly View
Open Or Shorted FPM Circuit
Faulty IFS Switch
Faulty FPDM
Faulty PCM
Open FPDM PWR Circuit; Or Open B+ Circuit To Constant Control Relay Module
(CCRM) (ZX2 & Mustang)
Faulty CCRM (ZX2 & Mustang)
Open Ground Circuit To CCRM (Mustang)
If DTC P1233 or P1234 is present in KOEO ON-DEMAND SELF-TEST, go to next step. If DTC
P1233 or P1234 is not present in KOEO ON-DEMAND SELF-TEST, PCM is now receiving a signal
from FPDM. DTC P1233 or P1234 may have been set due to Inertia Fuel Shutoff (IFS) switch
being tripped, then reset. If engine starts, go to step 25). If engine is now a no-start, disregard
DTCs P1233 and P1234 at this time and repeat QUICK TEST . If any other DTCs are present,
perform appropriate system test and repair as necessary. After repairing the engine no-start
condition, go to step 25) to diagnose intermittent causes of DTC P1233 or P1234.
2) Attempt To Start Engine Attempt to start engine. If engine starts, go to step 15). If engine does
not start, verify IFS switch is set (button depressed) and go to next step.
3) Check Power & Ground Circuits To FPDM Turn ignition switch to OFF position. Disconnect
FPDM connector. Turn ignition switch to ON position. Using a DVOM, measure voltage between
FPDM PWR circuit and GND circuit at FPDM harness connector. See Fig 1-Fig 3, and Fig 4 . If
voltage is more than 10.5 volts, replace FPDM. If voltage is 10.5 volts or less, go to next step.
4) Check Power To FPDM Turn ignition switch to ON position. Using a DVOM, measure voltage
between chassis ground and FPDM PWR circuit at FPDM harness connector. If voltage is more
than 10.5 volts, repair open ground circuit to FPDM. If voltage is 10.5 volts or less, go to next step
(Mustang and ZX2), or go to step 8) (all others).
5) Check B+ Voltage To CCRM (Mustang & ZX2) Turn ignition switch to OFF position. Disconnect
CCRM connector. On Mustang, CCRM is mounted on a bracket behind engine coolant reservoir.
On ZX2, CCRM is located in left front of engine compartment. On all models, measure voltage
between CCRM harness connector terminal No. 11 (B+ circuit) and chassis ground. See Fig 3, Fig
4 and Fig 6 . If voltage is more than 10.5 volts, go to next step (Mustang), or step 7) (ZX2). If
voltage is 10.5 volts or less, check condition of related fuse. If fuse is blown, check for short to
ground in B+ or FPDM PWR circuits to FPDM. Repair as necessary. If fuse is okay, repair open in
B+ circuit.
http://www2.prodemand.com/Print/Index?content=tabs&module=true&tab=true&terms=true&ymms=false&className=
7/21
5/15/2015
Printer Friendly View
Fig 6: Identifying Constant Control Relay Module Connector Terminals
Courtesy of FORD MOTOR CO.
6) Check GND Circuit To CCRM Using a DVOM, measure resistance of ground circuit between
chassis ground and CCRM harness connector terminal No. 18. If resistance is less than 5 ohms,
go to next step. If resistance is 5 ohms or more, repair open in ground circuit.
7) Check For Open FPDM PWR Circuit Using a DVOM, measure resistance of FPDM PWR circuit
between CCRM harness connector terminal No. 5 and FPDM harness connector terminal No. 2
(ZX2), or No. 9 (Mustang). If resistance is less than 5 ohms, replace CCRM. If resistance is 5 ohms
or more, FPDM PWR circuit is open. Go to step 13) to isolate fault.
8) Check B+ Voltage To FPDM Power Supply Relay Disconnect fuel pump relay in battery junction
box. Using a DVOM, measure voltage of B+ circuit between chassis ground and fuel pump relay
cavity No. 3. See Fig 2. If voltage is more than 10.5 volts, go to next step. If voltage is 10.5 volts or
less, check for blown B+ circuit fuse to fuel pump relay located in battery junction box in engine
compartment. If fuse is okay, repair open B+ circuit. If fuse is blown, check B+ or FPDM PWR
circuit for short to ground.
9) Check For GND To FPDM Power Supply Relay Turn ignition switch to OFF position. Disconnect
scan tool from DLC. Using a DVOM, measure resistance of GND circuit between negative battery
terminal and fuel pump relay cavity No. 2. See Fig 2. If resistance is less than 5 ohms, go to next
step. If resistance is 5 ohms or more, repair open in ground circuit.
10) Check For Open FPDM PWR Circuit Using a DVOM, measure resistance of FPDM PWR circuit
between FPDM power supply relay cavity No. 5 and FPDM harness connector terminal No. 9. See
Fig 2 and Fig 7 . If resistance is less than 5 ohms, reconnect FPDM and go to next step. If
resistance is 5 ohms or more, FPDM PWR circuit is open. Go to step 13) to isolate fault.
http://www2.prodemand.com/Print/Index?content=tabs&module=true&tab=true&terms=true&ymms=false&className=
8/21
5/15/2015
Printer Friendly View
Fig 7: Identifying Fuel Pump Driver Module Connector Terminals
Courtesy of FORD MOTOR CO.
11) Check VPWR Circuit (IGN START/RUN Circuit On Sable & Taurus) Voltage To FPDM Power
Supply Relay Turn ignition switch to ON position. Using a DVOM, measure voltage between
chassis ground and VPWR circuit (IGN START/RUN circuit on Sable and Taurus) at FPDM power
supply relay cavity No. 1. See Fig 2. If voltage is more than 10.5 volts, replace FPDM power supply
relay. If voltage is 10.5 volts or less, repair open in VPWR circuit (IGN START/RUN circuit on Sable
and Taurus). See WIRING DIAGRAMS .
NOTE: A break in step numbering sequence
occurs at this point. Procedure skips from step
11) to step 13). No test procedures have been
omitted.
13) Isolate Open In FPDM PWR Circuit Disconnect Inertia Fuel Shutoff (IFS) switch connector.
Perform the following:
On Mustang and ZX2, use a DVOM and measure resistance of FPDM PWR circuit
between IFS switch harness connector terminal No. 2 and CCRM harness connector
terminal No. 5. See Figure and Fig 6 .
On Focus, Sable and Taurus, measure resistance of FPDM PWR circuit between IFS
switch harness connector terminal No. 2 and FPDM power supply relay cavity No. 5. See
Figure and Fig 2 .
On all models, measure resistance of FPDM PWR circuit between FPDM harness
connector and IFS switch harness connector terminal No. 1. See Figure, Fig 2, Fig 3,
Fig 4 and Fig 7 .
http://www2.prodemand.com/Print/Index?content=tabs&module=true&tab=true&terms=true&ymms=false&className=
9/21
5/15/2015
Printer Friendly View
If all resistance measurements are less than 5 ohms, verify IFS switch is set (button depressed). If
IFS switch is set, replace IFS switch. If any resistance measurement is 5 ohms or more, repair
open in appropriate FPDM PWR circuit.
NOTE: A break in step numbering sequence
occurs at this point. Procedure skips from step
13) to step 15). No test procedures have been
omitted.
15) Check For Open FPM Circuit Turn ignition switch to OFF position. Disconnect FPDM and PCM
connector(s). Inspect connectors for loose, damaged or corroded terminals. Repair as necessary.
Using a DVOM, measure resistance of FPM circuit between PCM harness connector terminal No.
40 and FPDM harness connector terminal No. 4 (ZX2), or No. 7 (all others). See PCM
CONNECTOR IDENTIFICATION and Fig 7. If resistance is less than 5 ohms, go to next step. If
resistance is 5 ohms or more, repair open in FPM circuit.
16) Check FPM Circuit For Short To PWR In Harness Turn ignition switch to ON position. Using a
DVOM, measure voltage between PCM harness connector terminal No. 40 and chassis ground. If
voltage is less than one volt, go to next step. If voltage is one volt or more, repair short to PWR in
FPM circuit.
17) Check FPM Circuit For Short To Ground In Harness Turn ignition switch to OFF position.
Disconnect scan tool from Data Link Connector (DLC). Using a DVOM, measure resistance
between PCM harness connector terminal No. 40 and chassis ground. If resistance is more than
10 k/ohms, go to next step. If resistance is 10 k/ohms or less, repair short to ground in FPM circuit.
NOTE: In the following test step, it is normal
for voltage to cycle less than .02 volt and return
to .02-1.0 volt.
NOTE: A break in step numbering sequence
occurs at this point. Procedure skips from step
18) to step 25). No test procedures have been
omitted.
18) Check For FPM Output From FPDMReconnect FPDM connector. Turn ignition switch to ON
position. Using a DVOM, measure DC voltage between PCM harness connector terminals No. 40
and 51. If voltage is .02-1.0 DC volt, replace PCM. If voltage is not .02-1.0 DC volt, replace FPDM.
NOTE: With no fault detected, FPDM will
send a 50 percent duty cycle signal on FPM
circuit to PCM. FPM PID value should display 50
percent. Depending on scan tool being used,
some scan tools will display a random value of
85-115 percent.
NOTE: A break in step numbering sequence
occurs at this point. Procedure skips from step
http://www2.prodemand.com/Print/Index?content=tabs&module=true&tab=true&terms=true&ymms=false&className=
10/21
5/15/2015
Printer Friendly View
25) to step 30). No test procedures have been
omitted.
25) Check Circuits That May Cause An Intermittent Loss Of Power Supply To FPDM; Also Check
For Intermittent Opens Or Shorts On FPM CircuitTurn ignition switch to ON position. Using scan
tool, access FPM PID from PID/DATA MONITOR & RECORD menu. Observe FPM PID value for
indication of fault while performing the following:
Wiggle and bend all FPDM system related circuits (FPDM PWR or VPWR, and GND).
Wiggle and bend FPM circuit between PCM and FPDM.
On Mustang and ZX2, wiggle and bend B+ circuit to CCRM terminal No. 11.
On Mustang, wiggle and bend GND circuit to terminal No. 18 at CCRM.
On Focus, Sable and Taurus wiggle and bend B+ and GND circuits to FPDM power
supply relay.
Lightly tap on IFS switch, CCRM, FPDM and FPDM power supply relay to simulate road
shock.
A fault will be indicated if FPM PID value changes from 50 percent, or value stops fluctuating. If
any faults are found, isolate fault and repair as necessary. If no faults are found, concern cannot
be duplicated at this time. Go to TEST Z, step 1).
NOTE: For additional testing information,
see DIAGNOSTIC AIDS .
NOTE: DTC P1235 and P1236 are identical,
except DTC P1236 will not illuminate Malfunction
Indicator Lamp (MIL). On LS and Thunderbird,
FPDM functions are incorporated in Rear
Electronics Module (REM). Also, REM does not
use an FPM circuit. Diagnostic information will be
sent through SCP network. In the following steps,
if directed to perform an FPDM action, complete
the action using REM. See Fig 1-Fig 5 .
30) For KOEO & KOER Only DTC P1235 Or P1236: Check For These DTCs To Be Present In
KOEO Or KOER On-Demand Self-TestsThese DTCs indicate that FPDM has detected an invalid
or missing FP circuit signal from PCM. FPDM will send a message to PCM through FPM circuit,
indicating failure has been detected. PCM will set the DTC when message has been received.
Possible causes are:
Open Or Shorted FP Circuit
Faulty FPDM
Faulty PCM
If DTC P1235 or P1236 is present in KOEO or KOER self-test, DTC is a hard fault. Go to next
step. If DTC P1235 or P1236 is not present in KOEO or KOER self-test, check for an intermittent
fault. Go to step 42) (LS and Thunderbird), or go to step 45) (all others).
http://www2.prodemand.com/Print/Index?content=tabs&module=true&tab=true&terms=true&ymms=false&className=
11/21
5/15/2015
Printer Friendly View
31) Check For Open FP Circuit Between FPDM & PCM Turn ignition switch to OFF position.
Disconnect FPDM connector. Disconnect PCM connector(s). Inspect connector for loose,
damaged or corroded terminals. Repair as necessary. Using a DVOM, measure resistance of FP
circuit between PCM harness connector and FPDM harness connector (REM on LS and
Thunderbird). See Fig 1-Fig 5 . If resistance is less than 5 ohms, go to next step. If resistance is 5
ohms or more, repair open in FP circuit.
32) Check FP Circuit For Short To PWR In Harness Turn ignition switch to ON position. Using a
DVOM, measure voltage between chassis ground and FP circuit at PCM harness connector. If
voltage is less than one volt, go to next step. If voltage is one volt or more, repair short to PWR in
FP circuit.
33) Check FP Circuit For Short To Ground In Harness Turn ignition switch to OFF position.
Disconnect scan tool from DLC. Using a DVOM, measure resistance of FP circuit between PCM
harness connector and chassis ground. If resistance is 10 k/ohms or less, repair short to ground in
FP circuit. If resistance is more than 10 k/ohms, go to step 36) (LS and Thunderbird), or go to
next step (all others).
34) Check FP Circuit In FPDM Reconnect FPDM. Turn ignition switch to ON position. Using a
DVOM, measure voltage between PWR GND and FP circuits at PCM harness connector. See PCM
CONNECTOR IDENTIFICATION and Fig 1-Fig 5 . See PCM PWR GND, SIG RTN & VREF
TERMINAL IDENTIFICATION table. If voltage is 4.5-5.5 volts, replace PCM. If voltage is not 4.5-5.5
volts, replace FPDM.
NOTE: A break in step numbering sequence
occurs at this point. Procedure skips from step
34) to step 36). No test procedures have been
omitted.
NOTE: It is okay if FPF PID flashes to NO
during 20 second time period and changes back
to YES.
36) Check FPF PIDTurn ignition switch to ON position. Using scan tool, access FPF PID from
PID/DATA MONITOR & RECORD menu. Observe FPF PID for 20 seconds. If FPF PID indicated
YES during 20 second time period, go to step 40). If FPF PID indicates NO during whole 20
second time period, go to next step.
37) Check FP PID Using scan tool, access FP PID from PID/DATA MONITOR & RECORD menu. If
FP PID indicates 70-80 percent, go to next step. If FP PID does not indicate 70-80 percent, cycle
ignition switch to OFF, then to ON position and wait 5 seconds. Repeat this test step. If FP PID now
indicates 70-80 percent, go to next step. If FP PID still does not indicate 70-80 percent, replace
PCM.
NOTE: PWM_DC1 PID indicates signal sent
to REM from PCM on FP circuit.
NOTE: A break in step numbering sequence
occurs at this point. Procedure skips from step
38) to step 40). No test procedures have been
http://www2.prodemand.com/Print/Index?content=tabs&module=true&tab=true&terms=true&ymms=false&className=
12/21
5/15/2015
Printer Friendly View
omitted.
38) Access REM PIDs & Check PWM_DC1 PIDUsing scan tool, access PWM_DC1 PID from REM
menu. If PWM_DC1 PID indicates 70-80 percent, turn ignition switch to OFF position. No fault is
indicated. Disregard DTC P1235 or P1236 at this time and check for Continuous Memory DTCs. If
Continuous Memory DTCs are present, go to appropriate system test. See DIAGNOSTIC
TROUBLE CODE DEFINITIONS . If Continuous Memory DTCs are not present, testing is complete.
If PWM_DC1 PID does not indicate 70-80 percent, replace REM.
40) Check REM Harness Voltage On FP Circuit At PCM Turn ignition switch to OFF position.
Disconnect PCM connector "B". See PCM CONNECTOR IDENTIFICATION . Turn ignition switch to
ON position. Using a DVOM, measure voltage between PCM harness connector terminal B58 and
chassis ground. If voltage is more than 8 volts, replace PCM. If voltage is 8 volts or less, replace
REM.
NOTE: A break in step numbering sequence
occurs at this point. Procedure skips from step
40) to step 42). No test procedures have been
omitted.
NOTE: PWM_DC1 PID indicates signal sent
to REM from PCM on FP circuit.
NOTE: A break in step numbering sequence
occurs at this point. Procedure skips from step
42) to step 45). No test procedures have been
omitted.
42) Check FP Circuit For Intermittent ConcernsTurn ignition switch to ON position. Using scan tool,
access PWM_DC1 PID from REM menu. Observe PWM_DC1 PID value for indication of fault while
wiggling and bending FP circuit between REM and PCM. Fault will be indicated if PWM_DC1 PID
value changes. If any faults are found, isolate fault and repair as necessary. If no faults are found,
check for intermittent fault. Leave scan tool connected, go to TEST Z, step 1) and use FP and
PWM_DC1 PIDs for diagnosis of intermittent fault.
NOTE: With no fault detected, FPDM will
send a 50 percent duty cycle signal on FPM
circuit to PCM. FPM PID value should display 50
percent. Depending on scan tool being used,
some scan tools will display a random value
between 85-115 percent.
NOTE: A break in step numbering sequence
occurs at this point. Procedure skips from step
45) to step 47). No test procedures have been
omitted.
http://www2.prodemand.com/Print/Index?content=tabs&module=true&tab=true&terms=true&ymms=false&className=
13/21
5/15/2015
Printer Friendly View
45) Check FP Circuit For Intermittent Opens Or ShortsTurn ignition switch to ON position. Using
scan tool, access FPM PID from PID/DATA MONITOR & RECORD menu. Observe FPM PID for
indication of fault while wiggling and bending FP circuit between FPDM and PCM. Lightly tap on
FPDM to simulate road shock. Fault will be indicated if FPM PID value changes from 50 percent, or
value stops fluctuating. If any faults are found, isolate fault and repair as necessary. If no faults
are found, concern cannot be duplicated at this time. Go to TEST Z, step 1).
NOTE: For additional testing information,
see DIAGNOSTIC AIDS .
NOTE: DTC P1237 and P1238 are identical,
except DTC P1238 will not illuminate Malfunction
Indicator Lamp (MIL). On LS and Thunderbird,
FPDM functions are incorporated in Rear
Electronics Module (REM). Also, REM does not
use an FPM circuit. Diagnostic information will be
sent through SCP network. See Fig 1-Fig 5 .
47) For KOEO, KOER & Continuous Memory DTCs P1237, P1238 & P1641These DTCs indicate
FPDM has detected a fuel pump secondary circuit fault. Possible causes are:
Open Or Shorted FP PWR Circuit
Open FP RTN Circuit To FPDM
Open Or Shorted Circuit In Fuel Pump
Locked Fuel Pump Rotor
Faulty FPDM
On LS & Thunderbird, Circuits Associated With Fuel Pump Relay
If DTC P1237, P1238 or P1641 is present in KOEO or KOER self-test, the DTC is a hard fault. Go
to next step. If DTC P1237, P1238 or P1641 is not present in KOEO or KOER self-test, check for
intermittent fault. Go to step 67) (LS and Thunderbird), or go to step 56) (all others).
48) Attempt To Start Engine Attempt to start engine. If engine starts, go to step 80) (LS and
Thunderbird), or go to step 59) (all others). If engine is a no-start, go to step 61) (LS and
Thunderbird), or go to next step (all others) to diagnose fuel pump secondary circuits.
NOTE: If directed here from step 61), FPDM
functions are incorporated in Rear Electronics
Module (REM) for LS and Thunderbird. If
directed to perform an FPDM action, perform
action using REM. Refer to illustration. See Fig 5
for REM module circuit and terminal
identification.
49) Check FP PWR, FP RTN & Internal Fuel Pump Circuit ResistanceTurn ignition switch to OFF
position. Disconnect scan tool from DLC. Disconnect FPDM (or 20-pin REM) connector. Using a
DVOM, measure resistance between FP PWR and FP RTN circuits at FPDM (or REM) harness
http://www2.prodemand.com/Print/Index?content=tabs&module=true&tab=true&terms=true&ymms=false&className=
14/21
5/15/2015
Printer Friendly View
connector. See Fig 1-Fig 5 . If resistance is less than 10 ohms, go to next step. If resistance is 10
ohms or more, an open in secondary circuit exists. Go to step 54) to isolate fault.
50) Check FP RTN Circuit For Short To PWR In Harness Turn ignition switch to ON position. Using
a DVOM, measure voltage between chassis ground and FP RTN circuit at FPDM (or REM)
harness connector. If voltage is less than one volt, go to next step. If voltage is one volt or more,
repair short to PWR.
51) Check FP PWR Circuit For Short To Ground In Harness Turn ignition switch to OFF position.
Disconnect fuel pump connector. Using a DVOM, measure resistance of FP PWR circuit between
FPDM (or REM) harness connector and chassis ground. If resistance is more than 10 k/ohms, go
to next step. If resistance is 10 k/ohms or less, repair FP PWR circuit for short to ground.
NOTE: To perform this test step without a
scan tool, fuel pump can be commanded ON for
one second by cycling ignition switch from OFF
to ON position and repeating as necessary.
NOTE: A break in step numbering sequence
occurs at this point. Procedure skips from step
52) to step 54). No test procedures have been
omitted.
52) Check For VPWR To Fuel PumpReconnect FPDM (or REM) and scan tool. Turn ignition switch
to ON position. Connect DVOM between FP PWR and FP RTN circuits at fuel pump harness
connector. Using scan tool, access OUTPUT TEST MODE. See OUTPUT TEST MODE under
ADDITIONAL SYSTEM FUNCTIONS. Use scan tool and command OUTPUTS ON (or if no scan tool
is available cycle ignition switch to ON position). Fuel pump should turn on for about 5 seconds
(one second with ignition cycle). With fuel pump commanded ON, if voltage is more than 10 volts,
replace fuel pump. If voltage is 10 volts or less, verify vehicle battery is fully charged. Ensure fuel
pump command ON time did not time-out before voltage check was made. If battery charge is okay
and command ON time did not time-out, replace FPDM.
54) Isolate Open Circuit Turn ignition switch to OFF position. Disconnect fuel pump. Using a
DVOM, measure resistance of FP PWR circuit and of FP RTN circuit between fuel pump harness
connector and FPDM (or REM) harness connector. See Fig 1-Fig 5 . Using a DVOM, measure
internal resistance of fuel pump. If all resistance measurements are less than 10 ohms, no fault is
detected at this time. Verify results of previous steps. If any resistance measurement is 10 ohms or
more, repair open in FP PWR or FP RTN circuit, or if open is internal of fuel pump, replace fuel
pump.
NOTE: A break in step numbering sequence
occurs at this point. Procedure skips from step
54) to step 56). No test procedures have been
omitted.
NOTE: When FPDM is detecting a
secondary fuel pump circuit fault (wires going to
fuel pump), a 75 percent duty cycle signal will be
sent to PCM on FPM circuit. FPM PID value
http://www2.prodemand.com/Print/Index?content=tabs&module=true&tab=true&terms=true&ymms=false&className=
15/21
5/15/2015
Printer Friendly View
should display 75 percent. Depending on scan
tool being used, some scan tools will display a
random value between 250-400 percent.
56) Check For Intermittent DTC P1237, P1238 Or P1641Turn ignition switch to ON position. Using
scan tool, access FPM PID from PID/DATA MONITOR & RECORD menu. If FPM PID value is 75
percent or is varying between 250-400 percent, a hard fault is present, go to step 48). If FPM PID
value is not 75 percent or is not varying between 250-400 percent, DTC P1237, P1238 or P1641
is intermittent, go to next step.
NOTE: With no fault detected, FPDM will
send a 50 percent duty cycle signal on FPM
circuit to PCM. FPM PID value should display 50
percent. Depending on scan tool being used,
some scan tools will display a random value
between 85-115 percent.
57) Check Fuel Pump Secondary Circuits For Intermittent Open Or ShortTurn ignition switch to ON
position. Using scan tool, access FPM PID from PID/DATA MONITOR & RECORD menu. Observe
FPM PID value for indication of fault while wiggling and bending FP PWR and FP RTN circuits
between FPDM and fuel pump. Lightly tap on FPDM to simulate road shock. Fault will be indicated
by FPM PID value changing from 50 percent, or varying between 85-115 percent. If any faults are
found, isolate fault and repair as necessary. If no faults are found, go to next step.
58) Check FP PWR Circuit For Short To Ground Turn ignition switch to OFF position. Disconnect
FPDM. Connect a test light between FP PWR and FPDM PWR circuits at FPDM harness
connector. Turn ignition switch to ON position. Observe test light for indication of fault while
wiggling and bending FP PWR circuit between FPDM and fuel pump. If a fault is indicated, test light
will illuminate (indicating short to ground). If any faults are found, isolate fault and repair as
necessary. If no faults are found, concern cannot be identified at this time. Turn ignition switch to
OFF position, reconnect FPDM and go to TEST Z, step 1).
59) Check FP PWR Circuit For Short To PWR Turn ignition switch to OFF position. Disconnect
FPDM connector. Turn ignition switch to ON position. Using a DVOM, measure voltage between
chassis ground and FP PWR circuit at FPDM harness connector. See Fig 1-Fig 4 . If voltage is
less than one volt, go to next step. If voltage is one volt or more, repair FP PWR circuit for short to
PWR.
60) Check FP RTN Circuit For Short To Ground Ensure ignition switch is turned to ON position.
Using a DVOM, measure voltage between FPDM PWR and FP RTN circuits at FPDM harness
connector. If voltage is less than one volt, replace FPDM. If voltage is one volt or more, repair
short to ground in FP RTN circuit.
61) Check REM/FP PWR & GND Circuit To REM Harness Connector C420d (LS) or C420e
(Thunderbird) Terminals No. 1 & 2 Ensure Inertia Fuel Shutoff (IFS) switch is not tripped.
Disconnect REM connector C420d (LS) or C420e (Thunderbird). See Fig 5. Turn ignition switch to
ON position. Using a DVOM, measure voltage between REM/FP PWR and GND circuits at REM
harness connector C420d (LS) or C420e (Thunderbird). If voltage is 10.5 volts or less, go to next
step. If voltage is more than 10.5 volts, go to step 49).
62) Check REM/FP PWR Circuit Voltage To REM Using Chassis Ground As A Reference Ensure
ignition switch is turned to ON position. Using a DVOM, measure voltage between chassis ground
and REM/FP PWR circuit at REM harness connector C420d (LS) or C420e (Thunderbird). If
voltage is more than 10.5 volts, repair open GND circuit between REM harness connector C420d
http://www2.prodemand.com/Print/Index?content=tabs&module=true&tab=true&terms=true&ymms=false&className=
16/21
5/15/2015
Printer Friendly View
(LS) or C420e (Thunderbird) and ground point G401 located behind right side rear luggage
compartment panel. If voltage is 10.5 volts or less, go to next step.
NOTE: On LS, B+ circuit fuse to fuel pump
relay is No. 417 (15-amp). On Thunderbird, B+
circuit fuse to fuel pump relay is No. 418 (20amp).
63) Check For B+ To Fuel Pump Relay CavityTurn ignition switch to OFF position. Remove fuel
pump relay from battery junction box in engine compartment. Using a DVOM, measure voltage
between chassis ground and fuel pump relay cavity No. 3. See Figure and Fig 5 . If voltage is more
than 10.5 volts, go to next step. If voltage is 10.5 volts or less, check for blown B+ circuit fuse to
fuel pump relay, located in battery junction box. If fuse is blown, check for short to ground in B+
circuit, or short to power in FP RTN circuit before replacing fuse. If fuse is okay, repair open in
Red/Blue wire between B+ circuit fuse and fuel pump relay cavity No. 3.
64) Check For IGN START/RUN Voltage (Through IFS Switch) To Fuel Pump Relay Cavity Turn
ignition switch to OFF position. Disconnect REM 12-pin connector C420a (LS) or C420b
(Thunderbird). See Fig 5. Turn ignition switch to ON position. Using a DVOM, measure voltage
between chassis ground and IGN START/RUN circuit at REM harness connector C420a (LS) or
C420b (Thunderbird). If voltage is more than 10.5 volts, go to next step. If voltage is 10.5 volts or
less, check for blown fuse No. 204 (5-amp) in central junction box located behind right kick panel.
If fuse is blown, check for short to ground in IGN START/RUN circuit before replacing fuse. If fuse
is okay, go to step 69) to isolate open circuit.
65) Check Ground Circuit To Fuel Pump Relay Turn ignition switch to OFF position. Using a
DVOM, measure resistance of GND circuit between fuel pump relay cavity No. 1 and ground point
G300 (LS), or G401 (Thunderbird). See Figure and Fig 5 . See WIRING DIAGRAMS . If resistance
is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in GND circuit.
66) Check REM/FP PWR Circuit Continuity Using a DVOM, measure resistance of REM/FP PWR
circuit between fuel pump relay cavity No. 5 and REM harness connector C420d (LS) or C420e
(Thunderbird) terminal No. 1. See Figure and Fig 5 . If resistance is less than 5 ohms, replace fuel
pump relay. If resistance is 5 ohms or more, repair open in REM/FP PWR circuit.
67) Check REM/FP PWR, REM GND & Circuits Associated With Fuel Pump Relay For Intermittents
Turn ignition switch to OFF position. Disconnect REM 20-pin connector C420d (LS) or C420e
(Thunderbird), if not previously disconnected. See Fig 5. Connect test light between REM/FP PWR
and GND circuits at REM harness connector C420d (LS) or C420e (Thunderbird). Turn ignition
switch to ON position. Observe test light for indication of fault while wiggling and bending REM/FP
PWR and GND circuits to REM. Shake, wiggle and bend GND, IGN START/RUN and B+ circuits to
fuel pump relay. Lightly tap on fuel pump relay and IFS switch to simulate road shock. A fault is
indicated when test light goes off. If any faults are found, isolate fault and repair as necessary. If
no faults are found, go to next step.
68) Check FP PWR & FP RTN Circuits For Intermittent Concerns Turn ignition switch to OFF
position. Using a DVOM, measure resistance between FP PWR and FP RTN circuits at REM
connector C420d (LS) or C420e (Thunderbird). Observe DVOM for indication of fault while
wiggling and bending FP PWR and FP RTN circuits between REM and fuel pump. Perform same
procedure with DVOM connected between chassis ground and FP RTN circuit at REM connector
C420d (LS) or C420e (Thunderbird). A fault is indicated when resistance changes suddenly. If any
faults are found, isolate fault and repair as necessary. If no faults are found, concern cannot be
identified at this time. Turn ignition switch to OFF position. Remove DVOM, reconnect REM and go
to TEST Z, step 1).
http://www2.prodemand.com/Print/Index?content=tabs&module=true&tab=true&terms=true&ymms=false&className=
17/21
5/15/2015
Printer Friendly View
69) Isolate Open in IGN START/RUN Circuit Disconnect IFS switch. Using a DVOM, measure
resistance between (normally closed) IFS switch terminals. Record resistance reading. Also,
measure resistance of IGN START/RUN circuit between fuel pump relay cavity No. 2 and IFS switch
harness connector. See Fig 5. If both resistance measurements are less than 5 ohms, repair open
in IGN START/RUN circuit between fuse No. 204 (5-amp) in central junction box and IFS switch. If
resistance is 5 ohms or more in either measurement, replace IFS switch or repair open in IGN
START/RUN circuit between fuel pump relay cavity No. 2 and IFS switch. Ensure fuel pump motor
diode located in battery junction box in luggage compartment is okay. See WIRING DIAGRAMS .
NOTE: Diagnostic procedures beginning with
step 70) are performed when directed here from
TEST HC, step 2) to diagnose low voltage at fuel
pump and no DTCs are present.
70) Check Battery Voltage With Outputs Commanded OnTurn ignition switch to OFF position.
Connect scan tool to DLC. Disconnect fuel pump connector. Turn ignition switch to ON position.
Connect a DVOM between battery terminals. Using scan tool, access OUTPUT TEST MODE. See
OUTPUT TEST MODE under ADDITIONAL SYSTEM FUNCTIONS. While monitoring battery
voltage, command OUTPUTS ON. Record voltage measurement within 5 seconds of commanding
outputs ON. Command OUTPUTS OFF. If battery voltage is more than 11 volts, and go to next
step. If battery voltage is 11 volts or less, battery voltage is low. Service battery/charging system
as necessary. See appropriate GENERATORS & REGULATORS article in STARTING &
CHARGING SYSTEMS.
71) Check Ground Circuit To Fuel Pump Turn ignition switch to OFF position. Connect DVOM
between negative battery terminal and FP PWR circuit at fuel pump harness connector. See Fig 1Fig 5 . Turn ignition switch to ON position. Using scan tool, command OUTPUTS ON. Record
voltage measurement within 5 seconds of commanding outputs ON. If voltage is 10.5 volts or less,
ground circuit to fuel pump is okay. Go to next step. If voltage is more than 10.5 volts, locate and
repair high resistance in ground circuit to fuel pump. Check all wiring and connectors for fuel pump
and FPDM (or REM) for corrosion or damage. Check FPDM (or REM) ground connection to
chassis ground. Repair as necessary.
72) Check Voltage To FPDM Turn ignition switch to OFF position and proceed as follows:
LS & ThunderbirdDisconnect REM connector. Turn ignition switch to ON position. Using
a DVOM, measure voltage between negative battery terminal and REM/FP PWR circuit
at REM harness connector C420d (LS) or C420e (Thunderbird). See Fig 5. If voltage is
more than 10.5 volts, go to next step. If voltage is 10.5 volts or less, insufficient voltage
is being supplied to REM. Go to step 75).
All OthersDisconnect FPDM connector. Turn ignition switch to ON position. Using a
DVOM, measure voltage between negative battery terminal and FPDM PWR circuit at
FPDM harness connector. See Fig 1, Fig 2, Fig 3 or Fig 4 . If voltage is more than 10.5
volts, go to next step. If voltage is 10.5 volts or less, insufficient voltage is being
supplied to FPDM. Go to step 75).
73) Check FP PWR Circuit Turn ignition switch to OFF position and proceed as follows:
Focus, Sable & TaurusConnect a jumper wire between FPDM PWR and FP PWR
circuits at FPDM harness connector. Turn ignition switch to ON position. Using a DVOM,
measure voltage between negative battery terminal and FP PWR circuit at fuel pump
harness connector. If voltage is more than 10.5 volts and is within .5 volt of voltage
measured in step 72), turn ignition switch to OFF position and remove jumper. Ensure
all previous test step results are correct. Check all connectors for corrosion or damage.
http://www2.prodemand.com/Print/Index?content=tabs&module=true&tab=true&terms=true&ymms=false&className=
18/21
5/15/2015
Printer Friendly View
If all previous results are correct and connectors are okay, replace FPDM. If voltage is
not as specified, isolate high resistance in FP PWR circuit and repair as necessary.
Mustang & ZX2Connect a jumper wire between FPDM harness connector FPDM PWR
circuit and FP PWR circuit terminals. Turn ignition switch to ON position. Using a DVOM,
measure voltage between negative battery terminal and fuel pump harness connector
FP PWR terminal. If voltage is more than 10.5 volts, and is within .5 volt of voltage
measured in step 72), turn ignition switch to OFF position and remove jumper. Ensure
all previous test step results are correct. Check all connectors for corrosion or damage.
If all previous results are correct and connectors are okay, replace FPDM. If voltage is
not as specified, isolate high resistance in FP PWR circuit and repair as necessary.
LS & ThunderbirdConnect a jumper wire between FPDM harness connector REM/FP
PWR circuit and FP PWR circuit terminals. Turn ignition switch to ON position. Using a
DVOM, measure voltage between negative battery terminal and fuel pump harness
connector FP PWR terminal. If voltage is more than 10.5 volts and is within .5 volt of
voltage measured in step 72), turn ignition switch to OFF position and remove jumper.
Ensure all previous test step results are correct. Check all connectors for corrosion or
damage. If all previous results are correct and connectors are okay, replace REM. If
voltage is not as specified, isolate high resistance in FP PWR circuit and repair as
necessary.
NOTE: A break in step numbering sequence
occurs at this point. Procedure skips from step
73) to step 75). No test procedures have been
omitted.
75) Check B+ To PCM Power Relay, CCRM, Fuel Pump Relay Or FPDM Power Supply Relay Turn
ignition switch to OFF position and proceed as follows:
Focus, Sable & TaurusRemove FPDM power supply relay. Relay is located in battery
junction box in left rear corner of engine compartment. Turn ignition switch to ON
position. Using a DVOM, measure voltage between negative battery terminal and B+
circuit at FPDM power supply relay cavity No. 3. See Figure. If voltage is more than 10.5
volts, go to next step. If voltage is 10.5 volts or less, insufficient voltage is being
supplied to FPDM power supply relay. Check all related wiring and connectors on B+
circuit to FPDM power supply relay for corrosion or damage. Repair as necessary.
Mustang & ZX2Disconnect Constant Control Relay Module (CCRM). On Mustang,
CCRM is mounted on a bracket behind engine coolant reservoir. On ZX2, CCRM is
located in left front of engine compartment. On all models, turn ignition switch to ON
position. Using a DVOM, measure voltage between negative battery terminal and B+
circuit at CCRM harness connector. See Fig 3, Fig 4 and Fig 6 . If voltage is more than
10.5 volts, go to next step. If voltage is 10.5 volts or less, insufficient voltage is being
supplied to CCRM. Check all related wiring and connectors to CCRM for corrosion or
damage. Repair as necessary.
LS & ThunderbirdRemove fuel pump relay. Relay is located in battery junction box on
right side of luggage compartment. Turn ignition switch to ON position. Using a DVOM,
measure voltage between negative battery terminal and B+ circuit at fuel pump relay
cavity No. 3. See Fig 5. If voltage is more than 10.5 volts, go to next step. If voltage is
10.5 volts or less, insufficient voltage is being supplied to fuel pump relay. Check all
related wiring and connectors on B+ circuit to fuel pump relay for corrosion or damage.
Repair as necessary.
http://www2.prodemand.com/Print/Index?content=tabs&module=true&tab=true&terms=true&ymms=false&className=
19/21
5/15/2015
Printer Friendly View
76) Check FPDM PWR Circuit Turn ignition switch to OFF position and proceed as follows:
Focus, Sable & TaurusConnect a jumper wire between FPDM power supply relay
cavities No. 3 (B+) and No. 5 (FPDM PWR). See Figure. Using a DVOM, measure
voltage between negative battery terminal and FPDM PWR circuit at FPDM harness
connector. See Fig 2. If voltage is more than 10.5 volts, ensure all previous test step
results are correct. Check all connectors for corrosion or damage. If all previous results
are correct and connectors are okay, replace FPDM. If voltage is 10.5 volts or less,
isolate high resistance in system circuits and repair as necessary.
Mustang & ZX2Connect a jumper wire between CCRM harness connector terminals No.
11 (B+) and No. 5 (FPDM PWR). See Fig 3 and Fig 4 . Turn ignition switch to ON
position. Using a DVOM, measure voltage between negative battery terminal and FPDM
PWR circuit at FPDM harness connector. If voltage is more than 10.5 volts, ensure all
previous test step results are correct. Check all connectors for corrosion or damage. If
all previous results are correct and connectors are okay, replace FPDM. If voltage is
10.5 volts or less, isolate high resistance in system circuits and repair as necessary.
LS & ThunderbirdConnect a jumper wire between fuel pump relay cavities No. 3 (B+)
and No. 5 (REM/FP PWR). See Fig 5. Using a DVOM, measure voltage between
negative battery terminal and REM/FP PWR circuit at REM harness connector terminal
No. 1. If voltage is more than 10.5 volts, ensure all previous test step results are correct.
Check all connectors for corrosion or damage. If all previous results are correct and
connectors are okay, replace REM. If voltage is 10.5 volts or less, isolate high
resistance in system circuits and repair as necessary.
NOTE: A break in step numbering sequence
occurs at this point. Procedure skips from step
76) to step 80). No test procedures have been
omitted.
80) Check FP RTN Circuit For Short To Ground Turn ignition switch to OFF position. Disconnect
REM 20-pin connector C420d (LS) or C420e (Thunderbird). See Fig 5. Turn ignition switch to ON
position. Using a DVOM, measure voltage between REM harness connector C420d (LS) or C420e
(Thunderbird) terminals No. 1 (REM/FP PWR) and No. 12 (FP RTN). If voltage is less than one
volt, go to step 67). If voltage is one volt or more, repair short to ground in FP RTN circuit.
NOTE: A break in step numbering sequence
occurs at this point. Procedure skips from step
80) to step 85). No test procedures have been
omitted.
NOTE: Diagnostic procedures beginning with
step 85) are performed when directed here from
NO START/NORMAL CRANK symptom under
SYMPTOMS in TROUBLE SHOOTING - NO
CODES - CNG, FLEX-FUEL & GASOLINE
article.
85) Perform REM Self-Test To Verify IFS Switch Input To REMUsing scan tool, perform Rear
Electronics Module (REM) Self-Test. If DTC B2172 is present, go to next step. If DTC B2172 is not
http://www2.prodemand.com/Print/Index?content=tabs&module=true&tab=true&terms=true&ymms=false&className=
20/21
5/15/2015
Printer Friendly View
present, go to TEST A, step 1).
86) DTC B2172: Check IFS Switch Input Circuit To REM Turn ignition switch to OFF position.
Disconnect REM 12-pin connector C420a. See Fig 5. Turn ignition switch to ON position. Using a
DVOM, measure voltage between chassis ground and IFS INPUT circuit at REM harness connector
C420a (LS) or C420b (Thunderbird) terminal No. 8. If voltage is 10.5 volts or less, turn ignition
switch to OFF position and ensure IFS switch is not open. If IFS switch is okay, repair open circuit
between IFS switch and REM harness connector. If voltage is more than 10.5 volts, perform the
following:
If engine is a no-start and REM DTC B2172 was received in REM self-test mode,
replace REM.
If engine will start or REM DTC B2172 is a Continuous Memory DTC, DTC is
intermittent. If engine is a no-start, return to NO START/NORMAL CRANK symptom
under SYMPTOMS in TROUBLE SHOOTING - NO CODES - CNG, FLEX-FUEL &
GASOLINE article to continue diagnosis. If engine will start, go to TEST Z, step 1).
Although TEST Z is designed for PCM intermittents, TEST Z will help in REM intermittent
diagnosis.
http://www2.prodemand.com/Print/Index?content=tabs&module=true&tab=true&terms=true&ymms=false&className=
21/21