Spark

DTC P0628 or P0629

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 energises 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-energises the fuel pump relay after about 3 seconds.

P0628

The ECM detects a short circuit to ground or an open/high resistance on the fuel pump relay control circuit.

P0629

The ECM detects a short circuit to voltage on the fuel pump relay control circuit.

DTC P0628 and P0629 are Type C DTCs.

DTC P0628 and P0629 are Type C DTCs.

Schematic Reference

Engine Controls Schematics : Siemens ECM - LPG with LCP → Siemens ECM - Gas without FX3 or LCP → Delphi ECM - FX3

Connector End View Reference

Component Connector End Views

Electrical Information Reference

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information.

1. Ignition ON, command the fuel pump relay ON with a scan tool. You should hear an audible click for about 3-5 seconds.
2. Operate the vehicle within the Conditions For Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

1. Ignition OFF, disconnect the KR23A Fuel Pump Relay.
2. Ignition ON, verify that a test lamp illuminates between the relay coil ignition circuit terminal 85 and ground.

⇒	If the test lamp does not illuminate, test the relay coil ignition circuit for a short to ground or an open/high resistance.

3. Ignition OFF, connect a test lamp between the relay coil control circuit terminal 86 and the relay coil ignition circuit terminal 85.
4. Ignition ON, command the fuel pump relay ON with a scan tool. The test lamp should turn ON for about 3-5 seconds and then turn OFF.

⇒	If the test lamp is always ON, test the control circuit for a short to ground. If circuit tests normal, replace the K20 ECM.

⇒	If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If circuit tests normal, replace the K20 ECM.

5. If all circuits test normal, test or replace the KR23A Fuel Pump Relay.

1. Ignition OFF, disconnect the KR23A Fuel Pump Relay.
2. Test for 70-110 Ω between terminals 85 and 86.

⇒	If not within the specified range, replace the KR23A Fuel Pump Relay.

3. Test for infinite resistance between the following terminals:

•

30 and 86

•

30 and 87

•

30 and 85

•

85 and 87

⇒	If not the specified range, replace the KR23A Fuel Pump Relay.

4. Install a 20A fused jumper wire between relay terminal 85 and 12 V. Install a jumper wire between relay terminal 86 and ground. Test for less than 2 Ω between relay terminal 30 and 87.

⇒	If greater than the specified range, replace the KR23A Fuel Pump Relay.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.