Diagnostic Instructions
| • | Perform the Diagnostic System Check - Vehicle prior to using the diagnostic procedure. |
| • | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
| • | Diagnostic Procedure Instructions provides an overview of each diagnostic category. |
DTC Descriptor
DTC P0463: Fuel Level Sensor Circuit High VoltageDiagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
Fuel Level Sensor Reference Voltage Circuit | P0462 | -- | -- | P0461 |
Fuel Level Sensor Signal Circuit | P0462 | P0463 1 P0464 | P0463 | P0461 |
Fuel Level Sensor Low Reference Circuit | -- | P0463 1 P0464 | P0463 | P0461 |
1. Fuel Gage Inaccurate or Inoperative | ||||
Circuit Description
The engine control module (ECM)/powertrain control module (PCM) monitors the signal circuit of the fuel level sender in order to determine fuel level. The sender consists of a variable resistor that changes resistance based on the fuel level in the tank. The PCM monitors the voltage across the sender resistance in order to determine the fuel level. The ECM/PCM uses the signal circuit of the fuel level sender in order to calculate the total remaining fuel, in percent. The ECM/PCM sends the fuel level percent via the serial data circuit to the instrument cluster 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, with the engine ON.
Conditions for Setting the DTC
| • | The fuel level signal is greater than 5 volts. |
| • | The above condition is present for greater than 20 seconds. |
Action Taken When the DTC Sets
| • | The fuel gage defaults to empty. |
| • | The low fuel indicator illuminates. |
| • | The ECM/PCM records the operating conditions at the time the diagnostic fails. The ECM/PCM 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/PCM receives the clear code command from the scan tool. |
Reference Information
Fuel Level Specifications
Schematic Reference
| • | Engine Controls Schematics for the 4.2L engine |
| • | Engine Controls Schematics for the 5.3L engine |
| • | Engine Controls Schematics for the 6.0L engine |
Connector End View Reference
| • | Engine Control Module Connector End Views for the 5.3L engine |
| • | Engine Control Module Connector End Views for the 6.0L engine |
Electrical Information Reference
Scan Tool Reference
Circuit/System Verification
Ignition ON, observe the scan tool Fuel Tank Level Remaining parameter or the Fuel Level Sensor parameter. The reading should be between 4-98 percent.
Circuit/System Testing
- Ignition OFF, disconnect the harness connector at the fuel level sensor.
- Ignition OFF, test for less than 1 ohm of resistance between the low reference circuit and ground.
- Ignition ON, install a 3-amp fused jumper between the signal circuit and the low reference circuit. Verify the scan tool Fuel Tank Level Remaining parameter or the Fuel Level Sensor parameter is greater than 98 percent.
- If all circuits test normal, test or replace the fuel level sensor.
| ⇒ | 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/PCM. |
| ⇒ | If less than 98 percent, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the ECM/PCM. |
Component Testing
Measure the resistance of the float arm of the fuel level sender while moving the float arm between 40-250 ohms.
| ⇒ | If the resistance does not move smoothly across the specified range, replace the fuel level sensor. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Fuel Level Sensor Replacement for the 4.2L engine |
| • | Fuel Level Sensor Replacement for the 5.3L engine |
| • | Fuel Level Sensor Replacement for the 6.0L engine |
| • | Control Module References for the ECM/PCM replacement, setup, and programming |
