P0461

DTC P0461 (4.6L and 4.4L)

DTC Descriptor

DTC P0461
- Fuel Level Sensor 1 Performance

Diagnostic Fault Information

Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Initial Inspection and Diagnostic Overview






Circuit/System Description

The primary fuel level sender and the secondary fuel level sender changes resistance based on fuel level. The engine control module (ECM) monitors the signal circuits of the primary fuel level sender and the secondary fuel level sender in order to determine the fuel level. When the fuel tank is full, the resistances of both fuel level senders are low and the ECM senses a low signal voltage on both the signal circuits of the primary fuel level sender and the secondary fuel level sender. When the fuel tanks are empty, the resistances of the fuel level senders are high and the ECM senses a high signal voltage. The ECM uses the signal circuits of the primary fuel level sender and the secondary fuel level sender 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 instrument cluster in order to control the fuel gage. The fuel information is also used for misfire, evaporative emission (EVAP), and other onboard diagnostics.

Conditions for Running the DTC

The ignition is ON, with the engine running.

Conditions for Setting the DTC

The ECM does not detect a change in fuel level in the primary fuel tank of at least 3.0 L (0.79 gal) over a distance of 320 km (200 miles)

Action Taken When the DTC Sets

* The fuel gage defaults to empty.
* The driver information center (DIC) displays the FUEL LEVEL LOW message.
* 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 that there are no obstructions interfering with the fuel level sender.

• If any interference is present, remove the obstruction.

2. If no interference is present, 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 - Primary for the 4.6L engine
* Fuel Level Sensor Replacement - Primary for the 4.4L engine
* For the ECM replacement, setup, and programming Refer to Programming and Relearning Programming and Relearning