P0463

DTC P0463

DTC Descriptor

DTC P0463
- Fuel Level Sensor Circuit High Voltage

Diagnostic Fault Information

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






Circuit Description

The fuel level sensor changes resistance based on fuel level. The engine control module (ECM) monitors the signal circuit of the fuel level sensor in order to determine 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 total remaining fuel (percent) in the tank. The ECM sends the fuel level percent via the class 2 serial data circuit to the instrument panel cluster (IPC) in order to control the fuel gage. The fuel level information is also used for misfire and evaporative emission (EVAP) diagnostics.

Conditions for Running the DTC

* The ignition is ON.
* The system voltage is between 11-16 volts.

Conditions for Setting the DTC

* The fuel level signal voltage is greater than 3 volts (98 percent).
* The above condition is present for at least 10 seconds.

Action Taken When the DTC Sets

* The fuel gage defaults to empty.
* The check gages indicator illuminates.
* The ECM records the operating conditions at the time the diagnostic 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 the clear code command from the scan tool.

Circuit/System Verification

Ignition ON, observe the scan tool Fuel Level Sensor parameter. The reading should be between 0.9-2.5 volts.

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the fuel level sensor.
2. Ignition OFF, test for less than 1 ohm of resistance between the low reference circuit and ground.

• If greater than 1 ohm, test the low reference circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the ECM.

3. Ignition ON, install a 3-amp fused jumper between the signal circuit and the low reference circuit. Verify the scan tool Fuel Level Sensor parameter is less than 0.4 volt.

• If greater than 0.4 volt, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the ECM.

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

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure. Verification Tests

* Fuel Level Sensor Replacement
* Programming and Relearning for the ECM setup, and programming. Programming and Relearning