For 1990-2009 cars

### 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 P0462 : Fuel Level Sensor Circuit Low 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 sender changes resistance based on the 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 percent in the tank. The ECM sends the fuel level message via the serial data circuit to the body control module (BCM). The BCM sends the fuel level percent to the instrument panel cluster (IPC) via the serial data circuit for display on the fuel gage.

### Conditions for Running the DTC

The engine running.

### Conditions for Setting the DTC

• | The fuel level signal is greater than 98 percent.

• | The above condition is present for greater than 20 seconds.

### Action Taken When the DTC Sets

• | The fuel gage defaults to empty.

• | The ECM records the operating conditions at the time the diagnostic 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

### Circuit/System Verification

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

### Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the fuel level sensors.
2. Ignition ON, verify that the scan tool Fuel Tank Level Remaining parameter is less than 4 percent.

⇒ | If greater than the specified value, test the signal circuit terminal D for a short to ground. If the circuit tests normal, replace the ECM.

3. Ignition OFF, test for greater than 1 ohm between the signal circuit terminal C and ground.

⇒ | If less than the specified value, test the signal circuit for a short to ground.

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

### Component Testing

1. Ignition OFF, remove the primary and secondary fuel level sensors.
2. 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 D and the low reference terminal B.

⇒ | If not within the specified range, replace the primary fuel level sensor.

3. While sweeping the secondary 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 E and the low reference terminal B.

⇒ | If not within the specified range, replace the secondary fuel level sensor.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Primary Fuel Level Sensor Replacement

• | Secondary Fuel Level Sensor Replacement

• | Control Module References for ECM replacement, setup, and programming