Mike's Workshop Manuals: Service manuals for every vehicle
Home >> Jaguar >> 2000 >> XJ8 Base >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Self-Diagnostics >> Diagnostic Trouble Code Identification >> DTC P0066: Air Assist Close Valve Circuit Malfunction >> Diagnostic Test Procedure

Diagnostic Test Procedure

  1. Disconnect the AACV connector. See Figure. Turn ignition on. Measure voltage between AACV harness connector terminal No. 2 and ground. Is voltage less than 10 volts? If yes, repair wiring between AACV harness connector and battery as necessary. If no, go to next step. This circuit includes the EMS control relay, the EMS fuse box (fuse No. 12) and the high power protection module.
  2. Turn ignition off. Measure resistance between AACV harness connector terminal No. 3 and ground. Is resistance greater than 5 ohms? If yes, repair wiring as necessary. If no, go to next step.
  3. Disconnect negative battery cable. Disconnect the ECM connector EM83. Measure resistance between AACV harness connector terminal No. 1 and ECM harness connector EM83 terminal No. 3. Is resistance greater than 5 ohms? If yes, repair wiring as necessary. If no, go to next step.
  4. Reconnect battery negative cable. Measure voltage between AACV harness connector terminal No. 1 and ground. Is voltage greater than 1 volt? If yes, repair short to voltage. If no, go to next step.
  5. Measure resistance between AACV harness connector terminal No. 1 and ground. Is resistance less than 10,000 ohms? If yes, repair short to ground. If no, replace the AACV. If DTC resets, possible ECM failure.
scientia non olet · About Mike's Workshop Manuals