Mercedes-Benz vehicles such as GLA or CLA models will display Transmission Malfunction Stop when the Engine Control Unit (ECU) detects a problem that could potentially damage the transmission.
Mercedes-Benz Transmission Malfunction Stop can be caused by:
- faulty transmission control unit (TCU) firmware,
- low changing system voltage,
- low transmission fluid level,
- faulty transmission,
- or faulty engine control unit (ECU).
In most cases, pulling over, turning off the engine, and waiting a few minutes will reset the ECU and clears the transmission malfunction error.
- Transmission Malfunction Stop
- Check engine light on
- Vehicle stuck on limp mode
- Transmission shifts to position N automatically.
- Transmission shifts hard between cars
- Transmission lurches when placed in Drive
- Clunk when shifting from P to D
If restarting the engine doesn't work, reset the transmission adoption values following the procedure below.
- Turn the engine off.
- Turn the key to position II. All dashboard lights will turn on, but the engine should stay off. You can accomplish this by pressing the start button twice without pressing the brake pedal.
- Press the accelerator (throttle) pedal all the way to the floor to activate the kick-down switch.
- Hold the throttle pedal pressed down for 30 seconds.
- Take your foot off the throttle pedal and turn off the ignition by pressing the start/stop button one time.
- Wait 10 seconds, then restart the engine.
If the transmission malfunction error message returns have the vehicle diagnosed as soon as possible. Do not continue to drive with the transmission malfunction light on.
Mercedes-Benz constantly provides software updates to fix problems that cause the Transmission Malfunction Stop problem. If resetting the transmission doesn't fix the problem, call the dealer to check if a software update is available for your transmission.
The next step in the troubleshooting process is to read the fault codes from the transmission control module. Reading the codes from the transition module is very easy, and you can perform it yourself at home. Follow this guide to learn how to read Mercedes-Benz fault codes.