• | 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. |
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
---|---|---|---|---|
Fuel Level Sensor Reference Voltage Circuit | P0462 P2067 | -- | -- | P0461 P2066 |
Fuel Level Sensor 1 Signal Circuit Fuel Level Sensor 2 Signal Circuit | P0462 P2067 | P0463 P2068 | P0463 P2068 | P0461 P2066 |
Fuel Level Sensor Low Reference Circuit | -- | P0463 P2068 | P0463 P2068 | P0461 P2066 |
The primary fuel level sender and the secondary fuel level sender changes resistance based on fuel level. The engine control module (ECM) monitors the signal circuits of the primary fuel level sender and the secondary fuel level sender in order to determine the fuel level. When the fuel tank is full, the resistances of both fuel level senders are high and the ECM senses a high signal voltage on both the signal circuits of the primary fuel level sender and the secondary fuel level sender. When the fuel tanks are empty, the resistances of the fuel level senders are low and the ECM senses a low signal voltage. The ECM uses the signal circuits of the primary fuel level sender and the secondary fuel level sender in order to calculate the percentage of remaining fuel in the tank. The ECM sends the fuel level percentage via serial data circuit to the instrument cluster in order to control the fuel gage.
A partially filled fuel tank and filling the fuel tank with the ignition ON or engine RUNNING may cause an inaccurate or erratic fuel gage. This condition may cause a fuel system DTC to set and the fuel gage to default to empty. Refer to Fuel Gage Description and Operation.
• | Engine Control Module Connector End Views for the 6.0L engine |
• | Engine Controls Schematics for the 3.6L engine |
• | Engine Controls Schematics for the 2.8L engine |
• | Engine Controls Schematics for the 6.0L engine |
• | Engine Control Module Connector End Views for the 3.6L engine |
• | Engine Control Module Connector End Views for the 2.8L engine |
Fuel Gage Description and Operation
⇒ | If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuits tests normal, replace the ECM. |
⇒ | If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuits tests normal, replace the ECM. |
⇒ | If not displaying the specified range, test both signal circuits for an open/high resistance. If the circuits test normal, replace the ECM. |
⇒ | If the gage is incorrect, replace the IPC. |
⇒ | If not within the specified range, replace the primary fuel level sensor. |
⇒ | If not within the specified range, replace the secondary fuel level sensor. |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
• | Primary Fuel Level Sensor Replacement for the 6.0L engine |
• | Primary Fuel Level Sensor Replacement for the 3.6L engine |
• | Primary Fuel Level Sensor Replacement for the 2.8L engine |
• | Secondary Fuel Tank Module Replacement for the 6.0L engine |
• | Secondary Fuel Tank Module Replacement for the 3.6L engine |
• | Secondary Fuel Tank Module Replacement for the 2.8L engine |
• | Control Module References for ECM and IPC replacement, setup, and programming |