T_RET_MALFUNCT_ADC_BELOW; Retarder oil temperature sensor; Voltage below lower limit
â–¶ How to fix
Switch off ignition; Disconnect electronics; Connect transmission test cable; Measure resistance of the temperature sensor (pin 18) against the sensor ground terminal (pin 17) Nominal value: 20°C -> approx. 120 kohm, 80°C -> approx. 12 kohm, 140°C -> ca. 2 kohm; For additional values, see temperature sensor data sheet; 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
Reduced retarder torque;
Diagnostic depth
Detection
ADC value hot < 224, corresponds to > 195°C; Normal mode
Possible cause
Reduced retarder braking performance;