P0463

DTC P0463

DTC DESCRIPTOR
DTC P0463
Fuel Level Sensor Circuit High Voltage.

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 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 ECM senses a low signal voltage. When the fuel tank is empty, the sensor resistance is high and the ECM senses a high 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 the GMLAN message to the instrument panel cluster (IPC) in order to control the fuel gage and display the fuel level percent. Then 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 sensor output is greater than 2.9 volts.
- The above condition is present for greater than 30 seconds.

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.

REFERENCE INFORMATION

Fuel Level Specifications
Fuel Level Specifications (2.0L and 2.2L) Fuel Level Specifications (2.4L)

Schematic Reference
- Instrument Cluster Schematics
- Computers and Control Systems Schematics

Connector End View Reference
- Instrument Panel, Gages, and Console Connector End Views.
- Engine Control Module (ECM) Connector End Views

Electrical Information Reference
- Circuit Testing
- Connector Repairs
- Testing for Intermittent Conditions and Poor Connections
- Wiring Repairs

Scan Tool Reference
Scan Tool Data List

CIRCUIT/SYSTEM VERIFICATION
With the scan tool installed and the ignition ON, the Fuel Tank Level Remaining parameter in the ECM EVAP Data List indicates a value at or greater than 4 percent.

CIRCUIT/SYSTEM TESTING
1. With the ignition OFF, disconnect C305.
2. Connect a 3-ampere fused jumper wire between the signal circuit of the fuel level sensor and the low reference circuit of the fuel level sensor on the male terminal side of the connector.
3. With the ignition ON, install a scan tool and observe the Fuel Tank Level Remaining parameter in the ECM EVAP Data List.
- If the Fuel Tank Level Remaining parameter indicates a value less than 98 percent, check the signal circuit and the low reference circuit of the fuel level sensor for an open, a high resistance or a short to voltage.
- If both the signal circuit and the low reference circuit tests normal, replace the ECM.
- If the Fuel Tank Level Remaining parameter indicates a value greater than 98 percent, check the signal circuit and the low reference circuit of the fuel level sensor for an open, for a high resistance or a short to voltage between C305 and the fuel level sensor.
- If both the signal circuit and the low reference circuit tests normal between C305 and the fuel level sensor, replace the fuel level sensor.

REPAIR INSTRUCTIONS

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

- Fuel Level Sensor Replacement
- Control Module References for the ECM replacement, setup and programming.