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Home >> Jaguar >> 2000 >> XJ8 Base >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Self-Diagnostics >> Diagnostic Trouble Code Identification >> DTC P0405: EGR Valve Drive Circuits Open Circuit >> Diagnostic Test Procedure

Diagnostic Test Procedure

  1. Disconnect the EGR valve connector. Turn ignition on. Make sure the EMS relay is energized. Measure voltage between EGR harness connector terminal No. 2 and ground, and between terminal No. 5 and ground. Is voltage at both terminals greater than 10 volts? If yes, go to next step. If no, repair the circuit between the EGR harness connector and battery. This circuit includes the EMS relay and the EMS fuse box (fuse No. 10).
  2. Measure resistance between terminals No. 4 and 6 of the EGR valve. Measure resistance between terminals No. 1 and 3 of the EGR valve. Are both resistance readings greater than 80 ohms? If yes, go to next step. If no, install a New EGR valve.
  3. Measure resistance between terminals No. 2 and 3 of the EGR valve. Measure resistance between terminals No. 5 and 6 of the EGR valve. Are both resistances less than 80 ohms? If yes, go to next step. If no, install a new EGR valve.
  4. Disconnect negative battery cable. Disconnect ECM connector EM85. Measure resistance between EGR harness connector and ECM harness connector EM85 as follows:
    • EGR harness connector terminal No. 4 and ECM harness connector EM85 terminal No. 3.
    • EGR harness connector terminal No. 1 and ECM harness connector EM85 terminal No. 4.
    • EGR harness connector terminal No. 6 and ECM harness connector EM85 terminal No. 9.
    • EGR harness connector terminal No. 3 and ECM harness connector EM85 terminal No. 10.

    Is any of the resistance readings greater than 5 ohms? If yes, repair the high resistance in appropriate circuits as necessary. If no, go to next step.

  5. Reconnect negative battery cable. Measure voltage between EGR harness connector and ground as follows:
    • EGR harness connector terminal No. 4 and ground.
    • EGR harness connector terminal No. 1 and ground.
    • EGR harness connector terminal No. 6 and ground.
    • EGR harness connector terminal No. 3 and ground.

    Is any of the voltage readings greater than 10 volts? If yes, repair short to voltage in appropriate circuit as necessary. If no, go to next step.

  6. Measure resistance between EGR harness connector and ground as follows:
    • EGR harness connector terminal No. 4 and ground.
    • EGR harness connector terminal No. 1 and ground.
    • EGR harness connector terminal No. 6 and ground.
    • EGR harness connector terminal No. 3 and ground.

    Is any of the resistance readings less than 10,000 ohms? If yes, repair short to ground in appropriate circuit as necessary. If no, clear codes and retest system. If DTC resets, possible ECM failure.

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