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DTC U0101

08.08.2024
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U0101
Interaction between electronic units
Code: U0101 - Lost connection with TCM.

DTC U0101 means that the vehicle's control module has lost communication with the TCM (Transmission Control Module). This is the brain of the transmission, which receives signals from other systems and controls gear shifting. If the communication is lost, the transmission may go into limp mode or stop working altogether.

Error U0101 is most commonly found in vehicles with automatic transmissions from manufacturers like Ford, Chevrolet, Nissan, Honda, Volkswagen (VW), Citroen, SEAT, Toyota, and Chrysler. It is especially common in models with electromechanical or robotic transmissions.

Causes of U0101 error:

  • Wiring or connector problems. Contacts between the transmission control module and other systems can corrode, break, or disconnect due to vibration, moisture, or corrosion.
  • Faulty TCM module. If the transmission control module fails (due to overheating, factory defects, or voltage spikes), it stops transmitting data.
  • Problems with the CAN bus. The CAN bus is like the central network of the car, where commands are passed between modules. If there is a break or short circuit, communication with the TCM may be lost.
  • Dead or weak battery. The transmission electronics are sensitive to voltage, and if the battery is weak, the system may lose communication.
  • Software glitch. Sometimes the U0101 error appears after a firmware update, battery replacement, or reset of settings due to a software "bug".

How to fix U0101 error?

  • Turn off the ignition for 10–15 minutes. Sometimes a simple system reboot can help.
  • Check the battery. If it’s old or weak (below 12V), charge or replace it.
  • Inspect the connectors and wiring. Pay attention to the TCM module, which is often located near the transmission or in the engine compartment.
  • Try resetting the error with an OBD2 scanner. If it doesn't return, it might have been a temporary glitch.
  • If the problem persists, diagnose the TCM. It may need to be reprogrammed or replaced.
dtc u0101

Conclusion

The U0101 code indicates that the transmission "lost connection" with other systems. The cause may be bad wiring, a dead battery, or a malfunctioning control module. Start by checking the power supply, connectors, and resetting the error—if this doesn't help, you’ll need a specialist diagnosis.

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OBD U0101 code analysis and solutions

The page presents a detailed analysis of code U0101 for Opel, Renault, VW (Volkswagen), Ford, Peugeot, Mitsubishi, Skoda, BMW, Citroën, Toyota, Lada, Honda, Kia, and other models to investigate potential factors and solutions related to OBD 2 errors, with emphasis on the issue. We offer engineering documentation and approaches for diagnostics to identify and clarify the matter effectively. Our resource is designed to be a comprehensive source of information on OBD 2 errors, providing you with the necessary tools for successful repair and maintenance of auto. If during the fixing of OBD2 codes you need to purchase parts, don’t forget to visit Avtopro!