GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 HUMMER 🢒 2009 🢒 H2 🢒 Diagnostic Navigation 🢒 Vehicle Diagnostic Information 🢒 Fuel Gage Inaccurate or Inoperative

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.

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 Description

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

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, verify DTC P0461, P0462, P0463, or P0464 is not set

⇒If any of the DTCs are set, refer to Diagnostic Trouble Code (DTC) List - Vehicle.

Circuit/System Testing
  1. Ignition OFF, disconnect the harness connector at the fuel level sensor.
  2. Ignition OFF, test for less than 1.0 ohm between the low reference circuit terminal C and ground.
    3. ⇒If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the ECM.
  3. Install a Signal Generator and Instrument Panel Tester between the signal circuit terminal B and ground.
  4. Ignition ON, vary the signal generator resistance between 40 and 250 ohms. Verify that the scan tool Fuel Tank Level Remaining parameter displays a range that varies between 5 and 95 percent as the signal generator resistance changes.
    5. ⇒If not within the specified range, test the signal circuit for an open/high resistance. If the circuits test normal, replace the ECM.
  5. Vary the signal generator resistance between 40 and 250 ohms. Verify that the fuel gage varies between empty and full as the signal generator resistance changes.
    6. ⇒If the gage is incorrect, replace the IPC.
  6. If all circuits test normal, perform the fuel level sensor component test before replacing 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 value 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
    •  Control Module References for the ECM or IPC replacement, setup, and programming