DR_A_short circuit AIM
Switch off ignition; Disconnect electronics incl. transmission cables; Connect transmission checking cables; Measure resistance of the proportional valve against other proportional valves (pin 13 against pin 8/9/10/12/19/22/24), nominal value: 20 - 30 ohm; Measure resistance of the proportional valve against pin 12 and pin 11 if transmission partlist is 4255 xxx xxx / 4238 xxx xxx, nominal value: 20 - 30 ohm; Check cable TCU -> transmission; If you find deviations from nominal value, check wiring and component;
What you'll see
No driver-visible symptom recorded.
System reaction
Activate "Central Solenoid Disconnection Unit";
Diagnostic depth
The total current of all current regulators is higher than theoretically necessary Control frequency is higher than maximum permitted control frequency; One AIM switched on or both AIM switched on that have positive feedback
Transmission shifts to neutral (gear loss); Retarder is no longer available;;