Diagnostic Instructions
| • | Perform the Diagnostic System Check - Vehicle prior to using this 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 1 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, P0464 | P0463 | P0461 |
Fuel Level Sensor Low Reference Circuit | -- | P0463, P0464 | P0463 | P0461 |
Circuit/System Description
The fuel level sender changes resistance based on the fuel level. The engine control module (ECM) monitors the signal circuit of the fuel level sender in order to determine fuel level. When the fuel tank is full, the sender resistance is low and the ECM senses a low signal voltage. When the fuel tank is empty, the sender resistance is high and the ECM senses a high signal voltage. The ECM uses the signal circuit of the fuel level sender in order to calculate the total remaining fuel percent in the tank. The ECM sends the fuel level message via the serial data circuit to the instrument panel cluster (IPC) to display on the fuel gage. The fuel level information is also used for misfire and evaporative emission (EVAP) diagnostics.
This diagnostic tests for a lower than normal fuel level sender signal.
Conditions for Running the DTC
The ignition is ON, with the engine ON.
Conditions for Setting the DTC
| • | The fuel level signal is less than 3.5 percent. |
| • | The above condition is present for greater than 20 seconds. |
Action Taken When the DTC Sets
| • | The fuel gage defaults to empty. |
| • | 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. |
Diagnostic Aids
Using the Failure Records data may help locate an intermittent condition. If you cannot duplicate the DTC, the information in the Failure Records can help determine how many miles since the DTC set. The Fail Counter and Pass Counter can help determine how many ignition cycles that the diagnostic test reported a pass and/or a fail.
Reference Information
Schematic Reference
Connector End View Reference
Description and Operation
Electrical Information Reference
Scan Tool Reference
Circuit/System Testing
- Ignition OFF, disconnect the harness connector at the fuel level sensors.
- 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 is greater than 98 percent.
- If all circuits test normal, test or replace the fuel level sensors.
| ⇒ | 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. |
| ⇒ | 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. |
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.
| • | Control Module References for ECM replacement, setup, and programming |
