GM Service Manual Online
For 1990-2009 cars only

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 P0461: Fuel Level Sensor 1 Performance

Diagnostic Fault Information

Circuit

Short to Ground

High Resistance

Open

Short to Voltage

Signal Performance

Fuel Level Sensor 1 Signal

P0462

1

P0463

P0463

P0461

Fuel Level Sensor 2 Signal

P2067

1

P2068

P2068

P2066

Fuel Level Sensor Low Reference

--

1

P0463, P2068

P0463, P2068

P0461, P2066

1. Fuel Gage Inaccurate or Inoperative

Circuit/System Description

The primary fuel level sender and the secondary fuel level sender changes resistance based on fuel level. The engine control module (ECM) monitors the signal circuits of the primary fuel level sender and the secondary fuel level sender in order to determine the fuel level. When the fuel tank is full, the resistances of both fuel level senders are low and the ECM senses a low signal voltage on both the signal circuits of the primary fuel level sender and the secondary fuel level sender. When the fuel tanks are empty, the resistances of the fuel level senders are high and the ECM senses a high signal voltage. The ECM uses the signal circuits of the primary fuel level sender and the secondary fuel level sender in order to calculate the percentage of remaining fuel in the tank. The ECM sends the fuel level percentage via serial data circuit to the instrument cluster in order to control the fuel gage.

Conditions for Running the DTC

    • The engine is running.
    • No fuel level sensor signal failure present.
    • The system voltage is between 10-18 volts.

Conditions for Setting the DTC

    • The ECM does not detect a change in fuel level in the primary fuel tank of at least 45 percent over a distance of 120 km (75 miles).
    • The above condition is present for about 30 seconds.

Action Taken When the DTC Sets

    • The fuel gage defaults to empty.
    • The low fuel indicator illuminates.
    • The ECM records the operating conditions at the time that the diagnostic test fails. The ECM 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

Component Testing

  1. Ignition OFF, remove the primary fuel level sender and verify there are no obstructions interfering with the fuel level sender.
  2. If any interference is present, repair the fuel sender interference.
  3. Ignition OFF, disconnect the harness connector at the fuel level sensor.
  4. While sweeping the primary fuel level sensor through its full range of motion, test for a minimum value less than 41 ohms and a maximum value greater than 119 ohms between signal terminal 2 and the low reference terminal 4.
  5. If not within the specified range, replace the fuel level sensor.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Primary Fuel Tank Module Replacement
    •  Control Module References for ECM replacement, setup, and programming