Fuel Gage Inaccurate or Inoperative

Fuel Gage Inaccurate or Inoperative

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Initial Inspection and Diagnostic Overview
* Review Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions provides an overview of each diagnostic category.

Circuit/System Description

The fuel level sensor changes resistance in response to the fuel level. The engine control module (ECM) 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 ECM senses a low signal voltage. When the fuel tank is empty, the sensor resistance 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 circuit to the instrument cluster in order to control the fuel gage. The fuel information is also used for misfire and evaporative emission (EVAP) diagnostics.

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the fuel level sensor. Install a signal generator and instrument panel tester between the signal circuit and the low reference circuit.
2. Ignition ON, vary the resistance on the signal generator from 40 to 250 ohms. Verify that the scan tool Fuel Tank Level Remaining parameter displays the correct fuel level percent.

• If the fuel level percent is incorrect, test the signal circuit and the low reference circuit for an open/high resistance. If the circuits test normal, replace the ECM.

3. Ignition ON, vary the resistance on the signal generator from 40 to 250 ohms and monitor the fuel gage.

• If the gage is incorrect, replace the instrument panel cluster (IPC).

4. If all circuits test normal, test or replace the fuel level sensor.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

* Fuel Level Sensor Replacement for the 2.2L engine
* Fuel Level Sensor Replacement for the 2.4L engine
* Control Module References for ECM and IPC replacement, setup, and programming Verification Tests