• | 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 provide an overview of each diagnostic category. |
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
---|---|---|---|---|
Battery Voltage - Relay Switch | 1 | 2 | -- | -- |
Ignition 1 Voltage - Relay Coil | P1230 | P1230 | P0563 | -- |
Fuel Pump Supply Voltage | 1 | 2 | 3 | -- |
Fuel Pump Relay Control | P1230 | P1230 | P1231 | -- |
Fuel Pump Ground | -- | 2 | -- | -- |
|
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 energizes 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 de-energizes the fuel pump relay after about 3 seconds.
• | The ignition is ON or the engine is operating. |
• | The DTCs runs continuously once the above conditions are met. |
The ECM detects the fuel pump relay control circuit is open or shorted to ground.
The ECM detects the fuel pump relay control circuit control circuit is shorted to voltage.
DTC P1230 and P1231 are Type C DTCs.
DTC P1230 and P1231 are Type C DTCs.
The following table illustrates the fuel pump relay terminal location in the underhood fuse block:
ENGINE Relay Terminal Identification | |
---|---|
B+ - Switch | FP Relay Control |
Ignition 1 Voltage - Coil | FP Motor |
Front of Vehicle |
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
• | J 35616 GM-Approved Terminal Test Kit |
• | J 43244 Relay Puller Pliers |
Important: The test lamp is used to load the circuit and may not illuminate.
⇒ | If less than B+, repair the ignition 1 voltage circuit of the fuel pump relay for a short to ground or an open/high resistance. |
⇒ | If the test lamp remains ON all the time, test for a short to ground on the control circuit. If circuit/connections test normal, replace the ECM. |
⇒ | If the test lamp remains OFF all the time, test for a short to voltage or an open/high resistance on the control circuit. If circuit/connections test normal, replace the ECM. |
⇒ | If the resistance is not within the specified range, replace the fuel pump relay. |
• | 30 and 86 |
• | 30 and 87 |
• | 30 and 85 |
• | 85 and 87 |
⇒ | If continuity is detected, replace the fuel pump relay. |
⇒ | If the resistance measures more than 2 ohms, replace the fuel pump relay. |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
• | Control Module References for ECM replacement, setup, and programming |