P0461

DTC P0461

DTC DESCRIPTOR
DTC P0461: Fuel Level Sensor Circuit Performance




DIAGNOSTIC FAULT INFORMATION

IMPORTANT: Always perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Testing and Inspection

CIRCUIT/SYSTEM DESCRIPTION
The fuel level sensor changes resistance in response to the fuel level. The powertrain control module (PCM) or 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 PCM/ECM senses a low signal voltage. When the fuel tank is empty, the sensor resistance is high and the PCM/ECM senses a high 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 GMLAN serial data circuit to the body control module (BCM). The BCM sends a GMLAN 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.

This diagnostic tests for a stuck fuel level sensor signal. The PCM/ECM sets this DTC if the fuel level sensor signal appears to be stuck based on a lack of signal variation expected during normal operation.

CONDITIONS FOR RUNNING THE DTC
The engine is running.

CONDITIONS FOR SETTING THE DTC
The PCM/ECM does not detect a change in fuel level of at least 1.6 percent over a distance of 193 km (120 miles).

ACTION TAKEN WHEN THE DTC SETS
- The fuel gage defaults to empty.
- The low fuel indicator illuminates.
- 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 TESTING
1. With the ignition OFF, remove the fuel level sender.
2. Inspect for the following conditions:
- The fuel level sensor is stuck, perhaps due to an interference with the fuel strainer.
- The fuel tank contains foreign material for instance, ice.
- If any of the above condition is not present, 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 2.4L engine
- Fuel Sender Assembly Replacement for the 3.5L engine
- Fuel Level Sensor Replacement for the 3.9L engine
- Control Module References for the PCM/ECM replacement, setup, and programming