Download DTC P0461 Fuel Level Sensor Performance

PATH: Diagnostics > Diagnostic Routines > Powertrain > Engine Controls 7.4L > DTC P0461 Fuel Level Sensor Performance
DTC P0461 Fuel Level Sensor Performance
NOTE
Applicable vehicles:
 Chevy Pickup, GMC Pickup, Suburban, Tahoe, Yukon (VIN C/K)
DTC P0461 Fuel Level Sensor Performance
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Circuit Description
The Fuel Level sensor is an important input to the VCM for the Enhanced
Evaporative System Diagnostic. The VCM needs the fuel level information in
order to know the volume of fuel in the tank. The fuel level affects the rate of
change in the air pressure in the EVAP system. Several of the Enhanced
Evaporative System Diagnostic sub-test are dependent upon the correct fuel
level information. The diagnostic will not run when the tank is greater than 85
percent or less than 15 percent full. (This sensor signal disables the misfire
when the fuel levels are less than 15 percent). This DTC is a type C DTC.
Conditions for Running the DTC
The VCM has confirmed that the fuel tank is between 15 percent and 85
percent full.
Conditions for Setting the DTC
The VCM does not detect a decrease in fuel level over a distance of 200 miles
(320 Km).
Action Taken When the DTC Sets
 The control module stores the DTC in history after the first
failure but will not illuminate the malfunction indicator lamp
(MIL).
 The control module records the operating conditions at the
time the diagnostic fails. The control module stores the failure
information in the scan tools Freeze Frame/Failure Records.
Conditions for Clearing the MIL/DTC
The VCM turns OFF the MIL after 3 consecutive driving trips without a fault
condition present. A history DTC will clear if no fault conditions have been
detected for 40 warm-up cycles (the coolant temperature has risen 22°C (40°F)
from the start-up coolant temperature and the engine coolant temperature
exceeds 71°C (160°F) during that same ignition cycle) or the scan tool clearing
feature has been used.
Diagnostic Aids
WARNING
Important: Fuel level is used to determine EVAP system diagnosis. Always
diagnose the fuel level sensor before any other EVAP system components or
DTCs.
WARNING
Do not use the fuel gauge as an indication of a shorted or open circuit as the
IPC may always default to EMPTY or FULL depending upon the vehicle
model.
Check for the following conditions:
 A poor connection or damaged harness - Inspect VCM
harness connectors for the following:
 Backed out terminals
 Improper mating
 Broken locks
 Poor wire to terminal connections
 Intermittent test - monitor a scan tool or digital voltmeter
connected between the related circuits while moving the
connectors and harnesses. If the failure is induced, the voltage
reading will change. This will help locate a circuit problem.
Test Description
Number(s) below refer to the step number(s) on the diagnostic table.
2. This step determines if there is a wiring problem.
3. This step determines if the Fuel Level sensor signal and ground
circuits are OK.
Step
Action
Value(s)
Yes
No
Go to
Step 2
Go to
Powertrain
On Board
Diagnostic
(OBD)
System
Check
Go to
Step 3
Go to Step
4
Go to
Step 5
Go to Step
6
WARNING
1
Important: : Before clearing the
DTCs, use the scan tool Capture
Info to save the Freeze Frame and
Failure Records for reference. The
control module's data is deleted
once the Clear Info function is used.
--
Did you perform the Powertrain OnBoard Diagnostic (OBD) System
Check?
WARNING
Important: : If DTCs P0462 and
P0463 are also set, diagnose these
codes first.
2
3
1. Turn OFF the ignition.
2. Disconnect the Fuel Level
Sender electrical
connector at the fuel tank.
3. Turn ON the ignition
leaving the engine OFF.
4. Monitor the Fuel Level
sensor voltage using the
scan tool.
Is the Fuel Level voltage near the
specified value?
1. Jumper the Fuel Level
sensor signal and ground
circuits together.
2. Monitor the Fuel Level
sensor voltage using the
scan tool.
Is the Fuel Level sensor voltage near
5V
0V
Step
Value(s)
Yes
No
4
Repair the open or short to ground in
the Fuel Level signal circuit.
Is the action complete?
--
Go to
Step 11
Go to Step
9
5
Check the Fuel Level Sender for the
following:
 Corrosion and proper
mating at electrical
connections
 Proper alignment in
the fuel tank
 Restricted/binding
fuel level float
Was a problem found?
--
Go to
Step 7
Go to Step
8
6
Check the Fuel Level signal and
ground circuits for an open.
Was a problem found?
--
Go to
Step 7
Go to Step
9
7
Repair as necessary.
Is the action complete?
--
Go to
Step 11
--
8
Replace the Fuel Level Sender. Refer
to Fuel Sender Assembly
Replacement .
Is the action complete?
--
Go to
Step 11
--
1. Check terminal contact at
the VCM.
2. Repair terminal contact if
needed.
Was terminal contact repaired?
-Go to
Step 11
Go to Step
10
1. Replace the VCM.
2. Program the new VCM.
Refer to VCM
Replacement/Programmin
g.
3. Perform the VTD
Password Learn
Procedure. Refer to
Password Learn .
4. Perform the CKP System
--
Go to
Step 11
--
9
10
Action
the specified value?
Step
11
12
Action
Variation Learning
Procedure. Refer to
Crankshaft Position
System Variation Learn
.
Is the action complete?
1. Using the scan tool, clear
the DTCs.
2. Start the engine.
3. Select DTC and the
Specific DTC function.
4. Enter the DTC number
which was set.
5. Operate the vehicle, with
the Conditions for Setting
this DTC, until the scan
tool indicates the
diagnostic Ran.
Does the scan tool indicate the
diagnostic Passed?
Does the scan tool display any additional
undiagnosed DTCs?
Value(s)
Yes
No
Go to
Step 12
Go to Step
2
--
--
Go to
applicable
DTC
table
System OK