Possible causes of malfunction of the automatic transmission control unit:
Electrical:
* Open or short circuit in wiring
* Power outages
* Malfunction of sensors associated with the automatic transmission (speed sensor, gear selector position, etc.)
* Damage to connectors or electronic components
Mechanical:
* Wear or damage to internal mechanical components of the control unit
* Sticking or stuck solenoids
* Damage to the oil pump or torque converter
Software:
* Errors in the control unit software
* Software update failed
Other:
* Overheating of the automatic transmission or control unit
* Transmission fluid contamination
* External mechanical damage to the control unit
Signs of a faulty automatic transmission control unit:
* Gear shifting problems or refusal to shift
* Jerks or jolts when changing gears
*Increasing transmission temperature
* The transmission fault indicator on the dashboard lights up
* ‘Restriction’ or ’emergency’ mode
* Lack of response to gear shifting
Consequences of a malfunction of the automatic transmission control unit:
* Damage to the gearbox and other vehicle components
*Hazardous driving conditions due to loss of vehicle control
*High repair costs
Diagnostics and repair:
Diagnosis of a faulty automatic transmission control unit usually includes:
* Read fault codes using diagnostic scanner
* Checking wiring, sensors and other electrical components
* Internal inspection of the control unit
* Software check
Repair of the automatic transmission control unit may include:
* Replacement of faulty components
*Updating or reprogramming software
* Replacement of the entire control unit