Diagnostic Trouble Code (DTC) Information

Diagnostic trouble code (DTC) information

Condition




The transmission speed signal is transmitted by a sensor on the transmission. The transmission control module (TCM) uses the signal to determine the input shaft speed after the torque converter. This signal is used to compare the transmission speed and the vehicle speed. The transmission control module (TCM) uses this comparison to calculate the gear-shift timing. Transmission speed and vehicle speed data affects the adjustment of the system pressure, lock-up function control and engine torque reduction. The result is smooth gear-shifting. The control module calculates and compares the transmission speed, the engine speed (RPM) and the speed at the transmission. Diagnostic trouble code (DTC) TCM-0023 is stored if the control module registers that the signal from the transmission input speed sensor is missing.

Substitute value
- The transmission control module (TCM) "Emergency mode I" program has been initiated.

Possible source
- Contact resistance in the terminals
- Open-circuit in the power supply
- Open-circuit in the signal cable
- Defective speed sensor.

Fault symptom[s]
- Warning lamp for the automatic transmission flashes
- No lock-up function
- Harsh gear shifting.

Hint: Harsh gear shifting can be caused by:
- No reduction of the line pressure when shifting
- No reduction of the line pressure when moving the gear selector between positions P-R, N-R and N-D
- No request for torque limiting to the engine control module (ECM) when shifting.