Diagnostic trouble code (DTC) information
Condition
The transmission control module (TCM) calculates the ratio between the transmission input speed and the vehicle speed. There is a specific ratio for each gear. Diagnostic trouble code (DTC) TCM-0028 is stored if the control module registers that the ratio deviates by more than 10 % when the oil temperature is above +20°C (68 °F) and throttle opening exceeds 3 %.
Substitute Value
- The transmission control module (TCM) "Emergency mode I" program has been initiated.
Possible Source
- Contact resistance in the circuit for solenoids S1, S2, S3, S4, S5 and SLS.
- Solenoid S1 has jammed in the OFF position.
- Mechanical fault in the transmission. Worn components in the transmission causing slippage or too low line pressure.
Fault symptom[s]
- General orange warning lamp lit.
- Malfunction indicator lamp (MIL) lit.
- No lock-up function.
- Harsh gear shifting.
- No shifting.