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HOMESERVICE MANUALSCHRYSLER2013TOWN & COUNTRY S, GASREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 186 ((TRANSMISSION CONTROL MODULE (TCM) - ELECTRICAL DIAGNOSTICS))DTC TROUBLESHOOTINGU0121-LOST COMMUNICATION WITH ANTI-LOCK BRAKE MODULEDIAGNOSTIC TEST
2013 Chrysler Town & Country S, Gas

Diagnostic Test

2013 Chrysler Town & Country S, GasSECTION Diagnostic Test
WARNING: This page is about a different car, the 2013 Jeep Grand Cherokee. However, it is still accessible from the selected car via links, so may be relevant.
  1. CHECK FOR CAN C BUS COMMUNICATION DTCS 
    1. With the scan tool, check for CAN DTCs.

      Is DTC U0001-CAN C BUS DTC or U0121-LOST COMMUNICATION WITH ANTI-LOCK BRAKE MODULE set?

      Yes 

      • Refer to DTC INDEX and perform the appropriate diagnostic procedure. Perform the diagnostic procedure for U0001-CAN C BUS first if it is present.
      • Perform the NAG1 TRANSMISSION VERIFICATION TEST. Refer to STANDARD PROCEDURE .

      No 

      • Go To  2
  2. CHECK IF THE DTC IS CURRENT 
    NOTE:

    When the Transmission Control Module (TCM) detects and stores a DTC, the TCM also stores the vehicles operating conditions under which the DTC originally set. This information is located in the scan tool under Environmental Data. Before erasing any stored DTCs, record any available data to assist in duplicating the conditions in which the DTC originally set.

    1. Ignition on, engine not running.
    2. With the scan tool, erase Transmission DTCs.
    3. Using the Environmental Data recorded earlier, try to duplicate the conditions in which the DTC originally set. It may be necessary to test drive the vehicle.
    4. With the scan tool, read Transmission DTCs.

      Did the DTC U0121-LOST COMMUNICATION WITH ANTILOCK BRAKE MODULE reset?

      Yes 

      • Using the schematics as a guide, check the Transmission Control Module (TCM) pins, terminals, and connectors for corrosion, damage, or terminal push out. Pay particular attention to all power and ground circuits. If no problems are found, replace and program the TCM in accordance with the Service Information.
      • Perform the NAG1 TRANSMISSION VERIFICATION TEST. Refer to STANDARD PROCEDURE .

      No 

      • Go To  3
  3. CHECK THE WIRING AND CONNECTORS 
    1. The conditions necessary to set this DTC are not present at this time.
    2. Using the schematics as a guide, inspect the wiring and connectors specific to this circuit.
    3. Wiggle the wiring and connectors while checking for any possible open or shorted circuits.
    4. Check for any Service Information Tune-ups or Technical Service Bulletins that may apply.

      Were there any problems found?

      Yes 

      • Repair as necessary.
      • Perform the NAG1 TRANSMISSION VERIFICATION TEST. Refer to STANDARD PROCEDURE .

      No 

      • Test Complete.
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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.