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Home >> Jaguar >> 2000 >> XJ8 Base >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Self-Diagnostics >> Diagnostic Trouble Code Identification >> DTC P1224: Throttle Control Position Error >> Diagnostic Test Procedure
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Diagnostic Test Procedure

  1. Disconnect negative battery cable. Disconnect the TPS connector. Disconnect ECM connector EM81. Measure resistance between TPS connector terminal No. 3 and ECM harness connector EM81 terminal No. 10. Is resistance greater than 5 ohms? If yes, repair high resistance between TPS connector terminal No. 3 and ECM harness connector EM81 terminal No. 10. If no, go to next step.
  2. Reconnect negative battery cable. Remove the throttle motor power relay. Measure voltage between the throttle motor power relay connector terminal No. 3 and ground. Is voltage greater than 10 volts? If yes, go to next step. If no, repair circuit between the throttle motor power relay connector terminal No. 3 and the battery. This circuit includes the EMS fuse box (fuse No. 9).
  3. Turn ignition on. Measure voltage between the throttle motor power relay connector terminal No. 1 and ground. Is voltage greater than 10 volts? If yes, go to next step. If no, repair circuit between the throttle motor power relay connector terminal No. 1 and the battery. This circuit includes the EMS fuse box (fuse No. 14) and the EMS control relay.
  4. Disconnect negative battery cable. Disconnect ECM connector EM82. Measure resistance between ECM harness connector EM82 terminal No. 6 and throttle motor power relay connector terminal No. 2. Is resistance greater than 5 ohms? If yes, repair high resistance between ECM harness connector EM82 terminal No. 6 and throttle motor power relay connector terminal No. 2. If no, go to next step.
  5. Reconnect ECM connector EM82. Disconnect ECM connector EM80. Install the throttle motor power relay. Reconnect negative battery cable. Turn ignition on. Measure voltage between ground and ECM harness connector EM80 terminals No. 8 and 9. Is voltage greater than 10 volts? If yes, go to next step. If no, install a new throttle motor power relay.
  6. Disconnect the throttle motor connector. Measure resistance between throttle motor harness connector terminal No. 1 and ECM harness connector EM80 terminals No. 6 and 7. Are either resistance greater than 5 ohms? If yes, repair high resistance between throttle motor harness connector terminal No. 1 and ECM harness connector EM80 terminals No. 6 and 7. If no, go to next step.
  7. Measure resistance between throttle motor harness connector terminal No. 2 and ECM harness connector EM80 terminals No. 4 and 5. Are either resistance greater than 5 ohms? If yes, repair high resistance between throttle motor harness connector terminal No. 2 and ECM harness connector EM80 terminals No. 4 and 5. If no, go to next step.
  8. Reconnect ECM connector EM80. Turn ignition on. Measure voltage between throttle motor harness connector terminal No.1 and ground. Is voltage greater than 10 volts, repair short to voltage. If no, go to next step.
  9. Disconnect ECM connector EM80. Turn ignition off. Measure resistance between throttle motor harness connector terminal No. 1 and ground. Is resistance less than 10,000 ohms? If yes, repair short to ground. If no, install a new throttle body.
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