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Home >> Jeep >> 2010 >> Grand Cherokee SRT-8 >> Repair and Diagnosis >> Engine Performance >> Engine Control Systems >> (Front Control Module (FCM) - Electrical Diagnostics) >> DTC Troubleshooting >> U0100-Lost Communication With ECM/Pcm >> Diagnostic Test
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Diagnostic Test

  1. VERIFY THE DIAGNOSTIC TROUBLE CODE (DTC) IS ACTIVE 
    NOTE: Ensure the IOD fuse is installed and battery voltage is between 10 and 16 volts before proceeding.
    1. With the scan tool, read active DTCs.

      Is this DTC active?

      Yes 

      • Go to step  2

      No 

  2. CHECK FOR ANY OF THE FOLLOWING ACTIVE DTCS 
    1. With the scan tool, read all active DTCs from all modules.
      NOTE: Check for FCM configuration, CAN B or C hardware electrical, VIN Missing/Mismatch, battery or ignition related DTCs.

      Does the scan tool display any active DTCs to the conditions listed above?

      Yes 

      No 

      • Go to step  3
  3. VERIFY THAT THE ECM/PCM IS ACTIVE ON THE BUS 
    1. Turn the ignition on.
    2. With the scan tool, select Network View and select Advanced.
    3. Verify that the ECM/PCM is active on the bus.

      Is the ECM/PCM active on the bus?

      Yes 

      • Go to step  4

      No 

  4. CHECK FOR ADDITIONAL COMMUNICATION RELATED DTCS 
    1. With the scan tool, select Network View and select Advanced.

      Is there more than one module with active DTCs "Logged Against" the ECM/PCM?

      Yes 

      No 

      • Replace/update the module that set this DTC in accordance with the Service Information.
      • Perform the appropriate VERIFICATION TEST.