U0103 Lost communication with electric gear shift module

U0103 code - The transmisson control module TCM receives information from the engine, anti lock brake system, and the electronic gear shift control mudules over the CAN C bus. The CAN C bus is a high speed communication bus that allows real time control capability between various controllers. Most messages are sent every 20 mSec, this means critical information can be shared between multiple controllers almost instantaneously. The CAN C bus is a two wire bus with a CAN (+) and a CAN (-) circuit. To reduce the potential of radio and other electrical noise interference, the CAN bus circuit wiring is manufactured using a twisted pair configuration within the electrical wiring harness.

Set condition this DTC the DTC will set if a valid CAN ID was not received in the required time from the electronic gear shift module.

Possible causes U0103 code :

- Transmission control module (TCM)

Diagnostic test U0103 code 

Step 1. Check the TIPM for CAN C BUS communication DTCs

With the scan tool, check for TIPM DTCs.

Does the TIPM report the DTC U0001 CAN C BUS DTC or U 0100 Lost communication with ECM/PCM?

Yes, refer to totally integrated power (TIPM) diagnosis and testing. Perform the diagnostic procedure for U0001-CAN C Bus first if it is present. Perform NAG1 Transmission Verification Test.

No, go to step 2.

Step 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 the scan tool under environmental data. Before erasing any stored DTCs, record any available data to asist in duplicating the conditions in which the DTC originally set.

Ignition on, engine not running. With the scan tool, erase transmission DTCs. 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. With the scan tool, read transmission DTCs.

Did the DTC U0103 Lost communication with electric gear shift module reset?

Yes, using the schematics as a guide, check the transmission control module (TCM) terminals for corrosion, damage, or terminal push out. Pay particular attention to all power and ground circuits. If no problems are found, replace the TCM in accordance with the service information. Perform NAG1 Transmission Verification Test.

No, go to step 3.

Step 3. Check the wiring and connectors

The conditions necessary to set this DTC are not present at this time. Using the schematics as a guide, inspect the wiring and connectors specific to this circuit. Wiggle the wiring and connectors while checking for any possible open or shorted circuits. Perform any service information tune-ups or technical service bulletins that may apply.

Were there any problems found?

Yes, repair as necessary. Perform NAG1 Transmission Verification Test.

No, test complete.

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