Download DTC P0102 Mass Air Flow (MAF) Sensor Circuit Low

DTC P0102 Mass Air Flow (MAF) Sensor Circuit
Low Frequency
Circuit Description
The mass air flow (MAF) sensor measures the amount of air which passes through it into the engine during a
given time. The PCM uses the mass air flow information to monitor engine operating conditions for fuel delivery
calculations. A large quantity of air entering the engine indicates an acceleration or high load situation, while a
small quantity of air indicates deceleration or idle. The MAF sensor produces a frequency signal which can be
monitored using a scan tool. The frequency will vary within a range of around 2,000 Hertz at idle to about
10,000 Hertz at maximum engine load. DTC P0102 will be set if the signal frequency from the MAF sensor is
lower than the possible range of a normally operating MAF sensor.
Conditions for Setting the DTC


The engine is running.
MAF signal frequency is below 1200 Hertz

Above conditions present for longer than 3 seconds.
Action Taken When the DTC Sets



The PCM will illuminate the malfunction indicator lamp (MIL) the first time the malfunction is detected.
The PCM calculates an airflow value based on idle air control valve position, throttle position, RPM and
barometric pressure.
The PCM will store conditions which were present when the DTC set as Freeze Frame and Failure
Records data.
Conditions for Clearing the MIL/DTC



The PCM will turn OFF the MIL during the third consecutive trip in which the diagnostic has been run
and passed.
The History DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction.
The DTC can be cleared by using the scan tool.
Diagnostic Aids
A low minimum air rate can cause DTC P0102 to be set during deceleration. Check the minimum air rate as
follows:
1.
2.
3.
4.
5.
6.
Run the engine until fully warm (above 85°C / 185°F)
Disconnect the IAC.
Install IAC driver J 37027-A or equivalent.
With the engine idling, command the IAC valve to the fully extended position (0 counts).
With the IAC fully extended, observe the Mass Air Flow reading on the scan tool.
Check for conditions that can cause a low minimum air rate, including throttle bore and throttle plate
coking if the Mass Air Flow reading is below 2.27 g/sec.
7. If the minimum air rate is below specifications, clean or replace the throttle body as necessary.
Check for the following conditions:



Poor connection at PCM. Inspect harness connectors for backed out terminals, improper mating, broken
locks, improperly formed or damaged terminals, and poor terminal to wire connection.
Misrouted harness. Inspect the MAF sensor harness to ensure that it is not routed too close to high voltage
wires such as spark plug leads.
Damaged harness. Inspect the wiring harness for damage. If the harness appears to be OK, observe the
scan tool while moving connectors and wiring harnesses related to the MAF sensor. A change in the
display will indicate the location of the fault.

Plugged intake air duct or filter element. A wide-open throttle acceleration from a stop should cause the
Mass Air Flow displayed on a scan tool to increase from about 4-7 gm/s at idle to 100 gm/s or greater at
the time of the 1-2 shift. If not, check for a restriction.
If DTC P0102 cannot be duplicated, the information included in the Fail Records data can be useful in
determining vehicle mileage since the DTC was last set.
Test Description
Number(s) below refer to the Step number(s) on the Diagnostic Table:
2. This step verifies that the problem is present at idle.
5. A voltage reading of less than 4 or over 6 volts at the MAF sensor signal circuit indicates a fault in the
wiring or a poor connection.
6. Verifies that ignition feed voltage and a good ground are available at the MAF sensor.
13. This vehicle is equipped with a PCM which utilizes an Electrically Erasable Programmable Read Only
Memory (EEPROM). When the PCM is being replaced, the new PCM must be programmed.
DTC P0102 MAF Sensor
Circuit Low
Frequency
Step
1
2
Action
Was the Powertrain On-Board Diagnostic (OBD)
System Check performed?
1. Start the engine.
2. With the engine idling, monitor MAF
Frequency display on the scan tool.
Is MAF Frequency less than the specified value?
3
1. Turn ON the ignition switch.
2. Review and record scan tool Fail Records
data.
3. Operate the vehicle within Fail Records
Value(s)
Yes
No
Go to the Powertrain
Go to On Board Diagnostic
Step
(OBD) System
2
Check
1200 Hz
Go to
(1.2 kHz)
Step
4
Go to Step 3
Go to
Step Refer to Diagnostic
4
Aids
conditions as noted.
4. Using a scan tool, monitor Specific DTC
info for DTC P0102.
Does the scan tool indicate DTC P0102 failed this
ign?
1. Check for the following conditions:
- Objects blocking the MAF sensor inlet
screen.
- Vacuum leaks around the intake
manifold.
- Vacuum leaks at throttle body.
- Vacuum leaks at the EGR valve flange
4
and pipes.
- Crankcase ventilation valve faulty,
missing, or incorrectly installed.
- Low minimum air rate. Refer to
Diagnostic Aids.
7. If a problem is found, repair as necessary.
Was a problem found?
5
1.
2.
3.
4.
Turn OFF the ignition switch.
Disconnect the MAF sensor connector.
Turn ON the ignition switch.
Using a J 39200 Digital Multimeter, measure
voltage between the MAF signal circuit and
battery ground.
Is the voltage near the specified value?
6
Connect a J 35616-200 test light between the MAF
sensor ignition feed and ground circuits at the MAF
sensor harness connector.
Is the test light ON?
7
Connect a test light between MAF sensor ignition
feed circuit and battery ground.
Is the test light ON?
8
1. Check for a poor connection at the MAF
Go to
Step
14
Go to Step 5
Go to
Step
6
Go to Step 9
Go to
Step
8
Go to Step 7
Go to
Step
10
Go to Step 11
Go to
Go to Step 12
5V
sensor.
2. If a poor connection is found, replace faulty
terminal(s). Refer to Repair procedures in
Electrical Diagnosis.
Step
14
Was a problem found?
9
1. Check the MAF signal circuit between the
PCM and the MAF sensor for an open, short
to ground, short to the MAF ground circuit,
or short to voltage.
2. If the MAF signal circuit is open or shorted,
repair it as necessary. Refer to Repair
procedures in Electrical Diagnosis.
Was a problem found?
10
Locate and repair the open in the ground circuit to
the MAF sensor. Refer to Repair procedures in
Electrical Diagnosis.
Is action complete?
11
Locate and repair the open in the ignition feed
circuit to the MAF sensor. Refer to Repair
procedures in Electrical Diagnosis.
Is action complete?
12
Replace the MAF sensor. Go to Mass Air Flow
(MAF) Sensor Replacement .
Is action complete?
Go to
Step
14
Go to Step 13
Go to
Step
14
Go to
Step
14
Go to
Step
14
Replace the PCM.
13
Important:: The replacement PCM must be
programmed. Go to PCM
Replacement/Programming .
Is action complete?
14
1. Turn ON the ignition switch
2. Review and record scan tool Fail Records
data.
3. Clear DTCs.
4. Operate the vehicle within Fail Records
conditions as noted.
5. Using a scan tool, monitor Specific DTC
Go to
Step
14
Go to
Step
2
System OK
info for DTC P0102.
Does the scan tool indicate DTC P0102 failed this
ign?