DTC P0462 2.0L and 2.2L

The fuel level sender changes resistance based on the fuel level. The engine control module (ECM)/powertrain control module (PCM) 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 high and the ECM/PCM senses a high signal voltage. When the fuel tank is empty, the sender resistance is low and the ECM/PCM senses a low signal voltage. The ECM/PCM uses the signal circuit of the fuel level sender in order to calculate the total remaining fuel percent in the tank. The ECM/PCM sends the fuel level percent via the class 2 serial data circuit to the body control module (BCM). The BCM sends that class 2 message to the instrument panel cluster (IPC) in order to display the fuel level percent on the fuel gage. The fuel level information is also used for misfire and evaporative emission (EVAP) diagnostics.

This diagnostic tests for a lower than normal fuel level sender signal. Refer to Fuel Level Specifications in order to verify the correct fuel level sensor readings.

This diagnostic procedure supports the following DTC:

DTC P0462 Fuel Level Sensor Circuit Low Voltage

The ignition is ON, with the engine ON.

Use the Freeze Frame and/or Failure Records data in order to locate an intermittent condition. If you cannot duplicate the DTC, the information included in the Freeze Frame and/or Failure Records data may aid in determining the number of miles since the DTC set. The Fail Counter and Pass Counter can also aid in determining the number of ignition cycles that the diagnostic reported a pass and/or fail. Operate the vehicle within the same Freeze Frame conditions, i.e. RPM, engine load, vehicle speed, temperature, etc. This will isolate when the DTC failed.

Refer to Testing for Intermittent Conditions and Poor Connections .

The number below refers to the step number on the diagnostic table.

3. This step tests for the proper operation of the circuit in the high voltage range.

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

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 GMLAN serial data circuit to the body control module (BCM). The BCM sends the GMLAN message to the instrument panel cluster (IPC) in order to control the fuel gage and display the fuel level percent. Then fuel information is also used for misfire and evaporative emission (EVAP) diagnostics.

Fuel Level Specifications

Fuel Level Specifications

Schematic Reference

Connector End View Reference

Electrical Information Reference

Scan Tool Reference

Scan Tool Data List

With the scan tool installed and the ignition ON, the Fuel Tank Level Remaining parameter in the ECM EVAP Data List should indicate a value at or greater than 98 percent.

1. Ignition OFF, disconnect the fuel level sensor connector.
2. Ignition ON, with the scan tool observe the Fuel Tank Level Remaining parameter. Verify the Fuel Tank Level remaining parameter is 4 percent or less.

⇒	If the Fuel Tank Level Remaining parameter indicates a value greater than 4 percent, test the fuel level sensor signal circuit for a short to ground. If the fuel level sensor circuit tests normal, replace the ECM.

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

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