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Home >> Jaguar >> 2000 >> XJ8 Base >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Self-Diagnostics >> Diagnostic Trouble Code Identification >> DTC P1230: Fuel Pump Relay Malfunction >> Diagnostic Test Procedure
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Diagnostic Test Procedure

  1. Disconnect negative battery cable. Remove the fuel pump relay. Disconnect ECM connector EM83. Measure resistance between ECM harness connector EM83 terminal No. 4 and fuel pump relay connector terminal No. 2. Is resistance greater than 5 ohms? If yes, repair high resistance between ECM harness connector EM83 terminal No. 4 and fuel relay connector terminal No. 2. If no, go to next step.
  2. Reconnect negative battery cable. Turn ignition on. Measure voltage between ECM harness connector EM83 terminal No. 4 and ground. Is voltage greater than 10 volts? If yes, repair short to voltage. If no, go to next step.
  3. Turn ignition off. Measure resistance between ECM harness connector EM83 terminal No. 4 and ground. Is resistance less than 10,000 ohms? If yes, repair short to ground. If no, go to next step.
  4. Reconnect ECM connector EM83. Measure voltage between the fuel pump relay connector terminal No. 3 and ground. Is voltage less than 10 volts? If yes, repair the circuit between the fuel pump relay connector terminal No. 3 and the battery power bus. This circuit includes the trunk fuse box and the high power protection module. If no, go to next step.
  5. Turn ignition on. Measure voltage between the fuel pump relay connector terminal No. 1 and ground. Is voltage less than 10 volts? If yes, repair the circuit between the fuel pump relay connector terminal No. 1 and battery. This circuit includes the trunk fuse box (fuse No. 16 on XJ Series and fuse No. 3 on XK Series), the ignition positive relay and the high power protection module. If no, go to next step.
  6. Turn ignition on. Make sure the ignition positive relay is energized. Check the resistance between the fuel pump relay connector terminal No. 2 and ground. Is resistance greater than 5 ohm? If yes, possible ECM failure. If no, install a new fuel pump relay.
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