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 P0462: Fuel Level Sensor Circuit Low 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 sensor changes resistance in response to the fuel level. The powertrain control module (PCM)/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 fuel level sensor resistance is low and the PCM/ECM senses a low signal voltage. When the fuel tank is empty, the fuel level sensor resistance is high and the PCM/ECM senses a high signal voltage. The PCM/ECM uses the signal circuit of the fuel level sensor in order to calculate the percentage of fuel remaining in the tank. The PCM/ECM sends the fuel level percentage via serial data circuit to the instrument panel cluster (IPC). The PCM/ECM sends a serial data message to the IPC in order to display the fuel level in the fuel gage.
Conditions for Running the DTC
| • | The ignition is ON, with the engine running. |
| • | The system voltage is between 10-18 volts. |
Conditions for Setting the DTC
| • | The sender output is less than 0.5 volt. |
| • | The total resistance of the circuit is about or below 27.3 ohms. |
| • | The fuel level signal is 0 percent. |
| • | The above condition is present for greater than 10 seconds. |
Action Taken When the DTC Sets
| • | The fuel gage defaults to empty. |
| • | The low fuel indicator displays in the IPC. |
| • | The PCM/ECM records the operating conditions at the time that the diagnostic test fails. The PCM/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. |
Reference Information
Schematic Reference
| • | Engine Controls Schematics for the 3.8L engine |
| • | Engine Controls Schematics for the 5.3L engine |
Connector End View Reference
| • | Powertrain Control Module Connector End Views for the 3.8L engine |
| • | Engine Control Module Connector End Views for the 5.3L engine |
Description and Operation
Instrument Cluster Description and Operation
Electrical Information Reference
Scan Tool Reference
Circuit/System Verification
With the scan tool installed and the ignition ON, the Fuel Tank Level Remaining parameter in the ECM/PCM EVAP Data List should indicate a value at or greater than 98 percent.
Circuit/System Testing
- Ignition OFF, disconnect the harness connector at the fuel level sensor.
- Ignition ON, with the scan tool verify the Fuel Tank Level remaining parameter is 4 percent or less.
- If all circuits test normal, perform the fuel level sensor component test before replacing the fuel level sensor.
| ⇒ | If the Fuel Tank Level Remaining parameter indicates a value greater than 4 percent, test the signal circuit terminal B for a short to ground. If the fuel level sensor circuit tests normal, replace the ECM/PCM. |
Component Testing
- Ignition OFF, disconnect the harness connector at the fuel level sensor.
- While sweeping the fuel level sensor through its full range of motion, test for a minimum value less than 41 ohms and a maximum value greater than 119 ohms of resistance between signal terminal B and the low reference terminal C.
| ⇒ | If not within 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 3.8L engine |
| • | Fuel Level Sensor Replacement for the 5.3L engine |
| • | Control Module References for the PCM/ECM replacement, setup, and programming |
