LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Jeep >> 2016 >> Wrangler Rubicon, Automatic Trans >> Repair and Diagnosis >> Transmission >> Transmission Control Systems >> (Transmission Control Module (TCM) - Electrical Diagnostics) >> DTC Troubleshooting >> U0140-Lost Communication With Body Control Module >> Diagnostic Test
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Diagnostic Test

  1. VERIFY DTC IS ACTIVE 
    NOTE:

    Make sure the 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  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 BCM configuration, CAN 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 

      • Go to the DTC INDEX article and perform the appropriate diagnostic procedure.

      No 

      • Go To  3
  3. VERIFY THE TIPM IS ACTIVE ON THE BUS 
    1. Turn the ignition on.
    2. With the scan tool, verify the TIPM is active on the bus.

      Is the BCM active on the bus?

      Yes 

      • Go To  4

      No 

  4. CHECK FOR ADDITIONAL COMMUNICATION RELATED DTCS 
    1. With the scan tool, read all the DTCs.

      Is there more than one module with active DTCs "Logged Against" the BCM?

      Yes 

      No 

      • Go To  5
  5. CLEAR DTC IN MODULE SETTING FAULT 
    1. With the scan tool, select the module setting the DTC against the TIPM.
    2. Clear active DTCs.

      Is this DTC still active?

      Yes 

      • Replace/update the module that set this DTC in accordance with the Service Information.
      • Perform the appropriate verification test for the module being replaced. If there is no verification test for the associated module perform the TIPM VERIFICATION TEST. Refer to STANDARD PROCEDURE .

      No 

      • Go To  6
  6. CYCLE IGNITION 
    1. Cycle the ignition from RUN to OFF three times ending with the key in the RUN position.

      Does this DTC become active?

      Yes 

      • Go To  7

      No 

      • The condition is not present at this time. Using the wiring diagram/schematic as a guide, inspect the wiring for chafed, pierced, pinched and partially broken wires and the wiring harness connectors for broken, bent, pushed out and corroded terminals.
      • Perform the appropriate verification test for the module. If there is no verification test for the associated module perform the TIPM VERIFICATION TEST. Refer to STANDARD PROCEDURE .
  7. CHECK FOR ADDITIONAL LOST COMMUNICATION FAULTS 
    1. With the scan tool, view the modules.

      Does the TIPM and other CAN C BUS modules show Lost Communication with the remaining CAN C BUS modules?

      Yes 

      • Go To  8

      No 

      • Replace/update the module that set this DTC in accordance with the Service Information.
      • Perform the appropriate verification test for the module being replaced. If there is no verification test for the associated module perform the TIPM VERIFICATION TEST. Refer to STANDARD PROCEDURE .
  8. CHECK THE CAN C BUS (+) CIRCUIT FOR A SHORT TO VOLTAGE 
    1. Measure the voltage between the (D65) CAN C Bus (+) circuit and ground.

      Is the voltage above 5.0 volts?

      Yes 

      • Repair the short to voltage in the CAN C Bus (+) circuit. The short to voltage is present in one of the CAN C Bus circuits. Use the Star Connectors to isolate portions of the CAN C Bus in order to locate the concern.
      • Perform the TIPM VERIFICATION TEST. Refer to STANDARD PROCEDURE .

      No 

      • Go To  9
  9. CHECK THE CAN C BUS (-) CIRCUIT FOR A SHORT TO GROUND 
    1. Turn the ignition off.
    2. Measure the resistance between ground and the (D64) CAN C Bus (-) circuit.

      Is the resistance below 10k Ohms?

      Yes 

      • Repair the short to ground in the CAN C Bus (-) circuit. The short to ground is present in one of the CAN C Bus circuits. Use the Star Connectors to isolate portions of the CAN C Bus in order to locate the concern.
      • Perform the TIPM VERIFICATION TEST. Refer to STANDARD PROCEDURE .

      No 

      • Replace/update the module that set this DTC in accordance with the Service Information.
      • Perform the appropriate verification test for the module being replaced. If there is no verification test for the associated module perform the TIPM VERIFICATION TEST. Refer to STANDARD PROCEDURE .