• | 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 |
---|---|---|---|---|
Battery Voltage - Relay Switch | * | ** | -- | -- |
Ignition 1 Voltage - Relay Coil | P1230 | P1230 | P0563 | -- |
Fuel Pump Supply Voltage | * | ** | *** | -- |
Fuel Pump Relay Control | P1230 | P1230 | P1231 | -- |
Fuel Pump Ground | -- | ** | -- | -- |
* The fuel pump fuse opens and the engine cranks but does not run. ** The engine cranks but does not run. *** The fuel pump operates continuously and the battery will discharge. |
The engine control module (ECM) provides a ground to the coil side of the fuel pump relay. When the ignition switch is first turned ON, the ECM turns ON the fuel pump relay, which applies power to the fuel pump. The ECM enables the fuel pump relay as long as the engine is cranking or running, and crankshaft reference pulses are received. If no crankshaft reference pulses are received, the ECM turns OFF the fuel pump relay after about 3 seconds.
The following conditions may cause the fuel pump fuse to open:
• | The fuse is faulty. |
• | There is an intermittent short to ground in the supply voltage circuit of the fuel pump. |
• | The fuel pump has an intermittent internal condition. |
Control Module References for scan tool information
J 43244 Relay Puller Pliers
⇒ | If any DTCs are set, refer to Diagnostic Trouble Code (DTC) List - Vehicle. |
⇒ | If the fuel pump runs continuously, test the relay switch supply circuit for a short to voltage. If the circuit tests normal, replace the fuel pump relay. |
⇒ | If the fuel pump fuse is open, test the relay switch supply circuit for a short to ground. If the circuit tests normal, replace the fuel pump. |
⇒ | If less than B+, repair the relay switch B+ voltage circuit for an open/high resistance. |
⇒ | If the fuel pump does not turn ON, test for the following conditions: |
• | An open/high resistance in the relay switch supply circuit |
• | An open/high resistance in the ground circuit of the fuel pump |
⇒ | If the circuits test normal, replace the fuel pump. |
⇒ | If not within the specified range, replace the fuel pump relay. |
• | 30 and 86 |
• | 30 and 87 |
• | 30 and 85 |
• | 85 and 87 |
⇒ | If not the specified value, replace the fuel pump relay. |
⇒ | If greater than the specified range, replace the fuel pump relay. |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.