Buick Regal: Fuel Gauge Malfunction (FWD)
Diagnostic Instructions
- Perform the Diagnostic System Check - Vehicle prior to using this
diagnostic procedure.
- Review Strategy Based Diagnosis for an overview of the diagnostic
approach.
- Diagnostic Procedure Instructions provides an overview of each
diagnostic category.
DTC Descriptors
DTC P0461
Fuel Level Sensor Performance
DTC P0462
Fuel Level Sensor Circuit Low Voltage
DTC P0463
Fuel Level Sensor Circuit High Voltage
DTC P0464
Fuel Level Sensor Circuit Intermittent
Diagnostic Fault Information
1. Fuel Gauge Malfunction
Circuit/System Description
The fuel level sensor changes resistance based on fuel level and is wired to
the Fuel Pump Driver
Control Module. The Fuel Pump Driver Control Module sends the fuel level sensor
reading to the
Engine Control Module (ECM) via serial data. The ECM monitors the fuel level
sensor signal in order to
determine the fuel level. When the fuel tank is full, the resistances of the
fuel level sensor is low and the
ECM senses a low signal voltage on the signal circuit of the fuel level sensor.
When the fuel tank is
empty, the resistance of the fuel level sensor is high and the ECM senses a high
signal voltage. The ECM uses the signal circuit of the fuel level sensor in
order to calculate the percentage of remaining fuel
in the tank. The ECM sends the fuel level percentage via serial data to the body
control module (BCM).
The BCM then sends the fuel level percentage via serial data to the instrument
cluster in order to control
the fuel gauge. When the fuel level falls below approximately 11% the instrument
cluster illuminates the
low fuel level indicator.
Conditions for Running the DTC
- Ignition ON
- Battery voltage is between 11 - 32 V
Conditions for Setting the DTC
P0461
- The ECM detects a difference between the fuel consumed by the engine and
change of the fuel
level signal of less than 1 L (0.26 gal) over a range of 30 L (7.92 gal) or
45.6% of the primary fuel
tank.
- The above condition is present for about 300 seconds.
P0462
- The signal voltage is less than 0.25 V.
- The above conditions must be met for 5 seconds.
P0463
- The signal voltage is greater than 4.7 V.
- The above conditions must be met for 5 seconds.
P0464
- The fuel level change is greater than 10% for a duration lasting less
than 30 seconds.
- DTC P0464 runs and fails 2 out of 3 test cycles.
Action Taken When the DTC Sets
P0461, P0462, and P0463
- P0461, P0462, and P0463 are Type B DTCs
- The fuel gauge defaults to empty
- The low fuel indicator illuminates
P0464
Conditions for Clearing the DTC
- P0461, P0462, and P0463 are Type B DTCs
- P0464 is a Type A DTC
Reference Information
Schematic Reference
Instrument Cluster Wiring Schematics
Connector End View Reference
COMPONENT CONNECTOR END VIEW INDEX
Description and Operation
Instrument Cluster Description and Operation
Electrical Information Reference
- Circuit Testing
- Connector Repairs
- Testing for Intermittent Conditions and Poor Connections
- Wiring Repairs
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References for scan tool information.
Circuit/System Verification
Without UDV
1. Ignition ON.
2. Verify the fuel level gauge sweeps when performing the scan tool Instrument
Cluster Gauge
Sweep control function.
- If the fuel level gauge does not sweep
Replace the P16 Instrument Cluster
- Go to next step: If the fuel level gauge sweeps
3. Verify the low fuel level indicator turns ON and OFF when commanding the
scan tool All
Indicators control function ON and OFF.
- If the low fuel level indicator does not turn ON and OFF
Replace the P16 Instrument Cluster
- Go to next step: If the low fuel level indicator turns ON and OFF
4. Verify the scan tool Fuel Level Sensor parameter is between 0.5 - 3.5 V
and varies with fuel level.
- If not between 0.5 - 3.5 V or does not vary with fuel level
Refer to Circuit/System Testing
- Go to next step: If between 0.5 - 3.5 V and varies with fuel level
5. All OK.
With UDV
1. Ignition ON.
2. Verify the scan tool Fuel Level Sensor parameter is between 0.5 - 3.5 V and
varies with fuel level.
- If not between 0.5 - 3.5 V or does not vary with fuel level
Refer to Circuit/System Testing
- Go to next step: If between 0.5 - 3.5 V and varies with fuel level
3. All OK.
Circuit/System Testing
NOTE: Circuit/System Verification must be performed before proceeding
with
Circuit/System Testing.
1. Ignition OFF and all vehicle systems OFF, disconnect the harness connector
at the A7 Fuel Pump
and Level Sensor Assembly. It may take up to 2 minutes for all vehicle systems
to power down.
2. Test for less than 10 Ω between the low reference circuit terminal 2 and
ground.
- Ignition OFF, disconnect the harness connector at the K111 Fuel Pump
Driver Control
Module.
- Test for less than 2 Ω in the low reference circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, replace the K111 Fuel Pump Driver Control Module.
- Go to next step: If less than 10 Ω
3. Ignition ON.
4. Verify the scan tool Fuel Level Sensor Left Tank parameter is greater than
4.8 V.
- Ignition OFF, disconnect the harness connector at the K111 Fuel Pump
Driver Control
Module.
- Test for infinite resistance between the signal circuit terminal 1 and
ground.
- If less than infinite resistance, repair the short to ground on the
circuit.
- If infinite resistance, replace the K111 Fuel Pump Driver Control
Module.
- Go to next step: If greater than 4.8 V
5. Install a 3 A fused jumper wire between the signal circuit terminal 1 and
the low reference circuit
terminal 2.
6. Verify the scan tool Fuel Level Sensor Left Tank parameter is less than 0.2
V.
- Ignition OFF, disconnect the harness connector at the K111 Fuel Pump
Driver Control
Module, ignition ON.
- Test for less than 1 V between the signal circuit and ground.
- If 1 V or greater, repair the short to voltage on the circuit.
- Go to next step: If less than 1 V
- Ignition OFF
- Test for less than 2 Ω in the signal circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, replace the K111 Fuel Pump Driver Control Module.
- Go to next step: If less than 0.2 V
7. Test or replace the B46 Fuel Level Sensor.
8. Operate the vehicle within the Conditions for Running the DTC.
9. Verify the condition does not return.
Replace the K20 Engine Control Module.
- Go to next step: If the condition does not return
10. All OK.
Component Testing
1. Ignition OFF, remove the fuel level sensor.
2. Sweep the fuel level sensor through its full range of motion while measuring
resistance between
the signal terminal 1 and the low reference terminal 2.
3. Test for a minimum resistance value of 37-43 Ω and a maximum value of 245-255
Ω without any
spikes or dropouts.
- If minimum resistance is not 37-43 Ω, maximum resistance is not
245-255 Ω, or if
there are any spikes or dropouts
Replace the fuel level sensor.
- Go to next step: If minimum resistance is 37-43 Ω, maximum resistance
is 245-255 Ω,
and if there are no spikes or dropouts
4. All OK.
Repair Instructions
Perform the Diagnostic Repair Verification after completing the repair.
- Displays and Gauges Component Replacement Reference
- Control Module References for control module replacement, programming,
and setup.
READ NEXT:
Diagnostic Instructions
Perform the Diagnostic System Check - Vehicle prior to using this
diagnostic procedure.
Review Strategy Based Diagnosis for an overview of the diagnostic
approach.
Diag
Diagnostic Instructions
Perform the Diagnostic System Check - Vehicle prior to using this
diagnostic procedure.
Review Strategy Based Diagnosis for an overview of the diagnostic
approach.
Diag
Diagnostic Instructions
Perform the Diagnostic System Check prior to using this diagnostic
procedure: Diagnostic
System Check - Vehicle
Review the description of Strategy Based Diagnosis:Strateg
SEE MORE:
Diagnostic Instructions
Perform the Diagnostic System Check - Vehicle prior to using this
diagnostic procedure.
Review Strategy Based Diagnosis for an overview of the diagnostic
approach.
Diagnostic Procedure Instructions provide an overview of each diagnostic
category.
DTC Descriptors
DT
Diagnostic Instructions
Perform the Diagnostic System Check - Vehicle prior to using this
diagnostic procedure.
Review Strategy Based Diagnosis for an overview of the diagnostic
approach.
Diagnostic Procedure Instructions provides an overview of each
diagnostic category.
DTC Descriptors
D