GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Buick 🢒 2009 🢒 LaCrosse 🢒 Safety and Security 🢒 Supplemental Inflatable Restraints 🢒 DTC P0463

DTC P0463 3.8L, 5.3L, 6.0L, 6.2L, 7.0L Engines

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 Descriptor

DTC P0463: Fuel Level Sensor Circuit High Voltage

Diagnostic Fault Information

Circuit

Short to Ground

High Resistance

Open

Short to Voltage

Signal Performance

Fuel Level Sensor Signal

P0462

1

P0463, P0464

P0463

P0461

Fuel Level Sensor Low Reference

--

1

P0463, P0464

P0463

P0461

1. Fuel Gage Inaccurate or Inoperative

Circuit/System Description

The fuel level sensor changes resistance in response to the fuel level. The powertrain control module (PCM) monitors the signal circuit of the fuel level sensor in order to determine the fuel level. When the fuel tank is full, the sensor resistance is low and the PCM senses a low signal voltage. When the fuel tank is empty, the sensor resistance is high and the PCM senses a high signal voltage. The PCM uses the signal circuit of the fuel level sensor in order to calculate the percentage of fuel remaining in the tank. The PCM sends the fuel level percentage via serial data circuit to the instrument panel cluster (IPC). The PCM sends a serial data message to the IPC in order to display the fuel level in the fuel gage.

Conditions for Running the DTC
    • The ignition is ON, with the engine running.
    • The system voltage is between 10-18 volts.

Conditions for Setting the DTC
    • The fuel level signal is above 2.5 volts.
    • The fuel level signal is greater than 100 percent.
    • The above condition is present for greater than 10 seconds.

Action Taken When the DTC Sets
    • The fuel gage defaults to empty.
    • The low fuel indicator displays in the IPC.
    • The PCM records the operating conditions at the time that the diagnostic test fails. The PCM displays the failure information in the Failure Records on the scan tool.

Conditions for Clearing the DTC
    • The DTC becomes history when the conditions for setting the DTC are no longer present.
    • The history DTC clears after 40 malfunction-free warm-up cycles.

Reference Information

Schematic Reference

Instrument Cluster Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Instrument Cluster Description and Operation

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

Scan Tool Reference

Control Module References for Scan Tool Information

Circuit/System Verification

Ignition ON, observe the scan tool Fuel Tank Level Remaining parameter. The reading should be between 4 percent and 98 percent.

Circuit/System Testing
  1. Ignition OFF, disconnect the harness connector at the fuel level sensor.
  2. Ignition OFF, test for less than 1 ohm between the low reference circuit terminal C and ground.
    3. ⇒If greater than the specified range, test the low reference circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the PCM.
  3. Ignition ON, install a 3-amp fused jumper wire between the signal circuit terminal B and the low reference circuit terminal C. Verify the scan tool Fuel Tank Level Remaining parameter display is greater than 98 percent.
    4. ⇒If less than the specified range, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the PCM.
  4. If all circuits test normal, test or replace the fuel level sensor.

Component Testing
  1. Ignition OFF, remove the fuel level sender.
  2. While sweeping the fuel level sensor through its full range of motion, test for a minimum resistance value of less than 41 ohms and a maximum value greater than 119 ohms between the signal terminal B and the low reference terminal C.
    3. ⇒If not within the specified range, replace the fuel level sensor.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Fuel Level Sensor Replacement for the 3.8L engine
    •  Fuel Level Sensor Replacement for the 4.8L, 5.3L, 6.0L, 6.2L and 7.0L engines
    •  Control Module References for the PCM replacement, setup, and programming