• | 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 Pump Relay Ignition 1 Voltage | * | ** | -- | -- |
Fuel Pump Motor Supply Voltage | * | ** | *** | -- |
Fuel Pump Relay Control | ** | ** | *** | -- |
Fuel Pump Relay Ground | -- | ** | -- | -- |
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. |
When you turn ON the ignition switch, the engine control module (ECM) energizes the fuel pump relay which powers the fuel pump ON. The fuel pump remains ON as long as the engine is cranking or running and the ECM receives ignition reference pulses. If there are no ignition reference pulses, the ECM shuts the fuel pump OFF within 2 seconds after the ignition was switched to the ON position or if the engine stops.
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 the fuel pump runs continuously, test the relay switch supply circuit terminal 87 for a short to voltage. If the circuit tests normal, replace the fuel pump relay. |
⇒ | If greater than the specified range, repair the relay coil ground circuit for an open/high resistance. |
⇒ | If the test lamp does not illuminate, repair the relay switch B+ voltage circuit for a short to ground or 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 fuel pump ground circuit |
⇒ | If the above circuits test normal, replace the fuel pump. |
⇒ | If the test lamp is always ON, test the relay coil control circuit for a short to voltage. If the circuit tests normal, replace the ECM. |
⇒ | If the test lamp is always OFF, test the relay coil control circuit for a short to ground or an open/high resistance. If circuit tests normal, replace the ECM. |
⇒ | If not within the specified range, replace the relay. |
• | 30 and 86 |
• | 30 and 87 |
• | 30 and 85 |
• | 85 and 87 |
⇒ | If not the specified value, replace the relay. |
⇒ | If greater than the specified range, replace the relay. |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.