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Pinpoint Test O: DTC U1236 (A/CCM); CONTROL PANEL TO A/CCM SERIAL COMMUNICATION CIRCUIT FAULT

WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2006 Jaguar XKR, 2006 Jaguar XK8, 2005 Jaguar XKR, 2005 Jaguar XK8, and 2004 Jaguar XKR. However, it is still accessible from the selected car via links, so may be relevant.
  1. CHECK THE CONTROL PANEL TO A/CCM DATA CIRCUITS FOR HIGH RESISTANCE 

    Disconnect the AA/CCM electrical connector, AC03.

    Disconnect the control panel electrical connector, FC43.

    Measure the resistance between AC03, pin 03 (YG) and FC43, pin 04 (YG).

    Measure the resistance between AC03, pin 07 (Y) and FC43, pin 03 (Y).

    Is either resistance greater than 5 ohms? 

    YES:  REPAIR the high resistance circuit. For additional information, refer to the wiring diagrams. Test the system for normal operation.

    NO:  Go to step  2.

  2. CHECK THE CONTROL PANEL TO A/CCM DATA CIRCUITS FOR SHORT CIRCUIT TO BATTERY 

    Measure the voltage between AC03, pin 03 (YG) and GROUND.

    Measure the voltage between AC03, pin 07 (Y) and GROUND.

    Is either voltage greater than 3 volts? 

    YES:  REPAIR the short circuit. For additional information, refer to the wiring diagrams. Test the system for normal operation.

    NO:  Go to step  3.

  3. CHECK THE CONTROL PANEL TO A/CCM DATA CIRCUITS FOR SHORT CIRCUIT TO IGNITION + 

    Turn the ignition switch to the ON position.

    Measure the voltage between AC03, pin 03 (YG) and GROUND.

    Measure the voltage between AC03, pin 07 (Y) and GROUND.

    Is either voltage greater than 3 volts? 

    YES:  REPAIR the short circuit. For additional information, refer to the wiring diagrams. Test the system for normal operation.

    NO:  Go to step  4.

  4. CHECK THE CONTROL PANEL TO A/CCM DATA CIRCUITS FOR SHORT CIRCUIT TO GROUND 

    Turn the ignition switch to the OFF position.

    Measure the resistance between AC03, pin 03 (YG) and GROUND.

    Measure the resistance between AC03, pin 07 (Y) and GROUND.

    Is either resistance less than 10,000 ohms? 

    YES:  REPAIR the short circuit. For additional information, refer to the wiring diagrams. Test the system for normal operation.

    NO:  INSTALL a new control panel. Refer to Control Components . Test the system for normal operation.

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