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. Initial Inspection and Diagnostic Overview






Circuit/System Description

The fuel level sensor changes resistance in response to the fuel level. The 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 high and the ECM senses a high signal voltage. When the fuel tank is empty, the sensor resistance is low and the ECM senses a low 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 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.

Conditions for Running the DTC

The engine is running.

Conditions for Setting the DTC

The 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 ECM records the operating conditions at the time that the diagnostic test 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.
* The ECM receives a clear code command from the scan tool.

Circuit/System Testing

1. Ignition OFF, remove the fuel level sender and verify there are no objects interfering with the fuel level sender.

• Repair any fuel level sender interference.

2. Replace the fuel level sender.

Repair Instructions

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

* Fuel Level Sensor Replacement for the 5.3L engine
* Fuel Sender Assembly Replacement for the 3.5L engine
* Fuel Level Sensor Replacement for the 3.9L engine
* Programming and Relearning Programming and Relearning