Extended Sedan

DTC P0462 (Extended Sedan)

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.






Circuit/System Description

The fuel level sensor changes resistance in response to the fuel level. The powertrain control module (PCM) 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 PCM senses a low signal voltage. When the fuel tank is empty, the sensor resistance is high and the PCM senses a high signal voltage. The PCM uses the signal circuit of the fuel level sensor in order to calculate the percentage of remaining fuel in the tank. The PCM sends the fuel level percentage via GMLAN serial data circuit 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 9-16 volts.

Conditions for Setting the DTC

- The sender output is less than 0.39 volts.
- 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 illuminates.
- The PCM records the operating conditions at the time that the diagnostic test fails. The PCM 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 receives a clear code command from the scan tool.

Circuit/System Verification

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

Circuit/System Testing

1. With the ignition OFF, disconnect C413.
2. With the ignition ON, install a scan tool and observe the Fuel Tank Level Remaining parameter in the PCM EVAP Data List.
-> If the Fuel Tank Level Remaining parameter indicates a value less than 4 percent, check the signal circuit of the fuel level sensor for a short to ground between C413 and the fuel level sensor.
-> If the fuel level sensor circuit tests normal between C413 and the fuel level sensor, replace the fuel level sensor.
-> If the Fuel Tank Level Remaining parameter indicates a value greater than 4 percent, check the signal circuit of the fuel level sensor circuit for a short to ground between C413 and the PCM.
-> If the fuel level sensor circuit tests normal between C413 and the PCM replace the PCM.