P0462

DTC P0462

DTC Descriptor

DTC P0462
- Fuel Level Sensor Circuit Low Voltage

Diagnostic Fault Information

Important: Always perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Initial Inspection and Diagnostic Overview






Circuit/System Description

The fuel level sensor changes resistance in response to the fuel level. The powertrain control module (PCM)/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 high and the PCM/ECM senses a high signal voltage. When the fuel tank is empty, the sensor resistance is low and the PCM/ECM senses a low signal voltage. The PCM/ECM uses the signal circuit of the fuel level sensor in order to calculate the percentage of remaining fuel in the tank. The PCM/ECM sends the fuel level percentage via serial data circuit to the PCM/ECM. The PCM/ECM sends a serial data message to the instrument panel cluster (IPC) in order to display the fuel level percent on the fuel gage. The fuel information is also used for misfire and evaporative emission (EVAP) diagnostics.

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 sender output is less than 0.5 volt.
* The total resistance of the circuit is about or below 27.3 ohms.
* The fuel level signal is 0 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/ECM records the operating conditions at the time that the diagnostic test fails. The PCM/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.
* The PCM/ECM receives a clear code command from the scan tool.

Circuit/System Verification

With the scan tool installed and the ignition ON, the Fuel Level Sensor Voltage parameter in the PCM/ECM EVAP Data List should indicate a value at or lower than 0.5 volts.

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the fuel level sensor.
2. Ignition ON, with the scan tool observe the Fuel Level Sensor Voltage parameter. Verify the Fuel Level Sensor Voltage parameter is 4 volts or greater.

• If the Fuel Level Sensor Voltage parameter indicates a value less than 4 volts, test the fuel level sensor signal circuit for a short to ground. If the fuel level sensor circuit tests normal, replace the PCM/ECM.

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

Repair Instructions

Important: Always perform the Diagnostic Repair Verification after completing the diagnostic procedure. Verification Tests

* Fuel Level Sensor Replacement for the 3.8L engine
* Fuel Level Sensor Replacement for the 5.3L engine
* Programming and RelearningProgramming and Relearning