Trouble Code Conditions

Special Tools:
- 981 3190
- 998 8686

Trouble Code Conditions
- The combined instrument panel supplies the transmission control module (TCM) with vehicle speed information. The signal is a variable-frequency uniform square wave where frequency increases with road speed. The transmission control module uses the signal to select the correct gear. The transmission control module also uses the transmission speed sensor signal to determine vehicle speed. Diagnostic trouble code (DTC) AT-232 is stored if the transmission control module registers that the vehicle speed sensor (VSS) signal from the combined instrument panel is missing.

Substitute value(s)
- The transmission control module "Emergency mode II" program is initiated.

Possible source(s)
- Open-circuit in signal cable.
- Short-circuit to supply voltage or ground in the signal cable.
- Defective combined instrument panel.
- Fault in vehicle speed sensor circuit.
- Contact resistance in terminals.

Fault symptom(s)
- The combined instrument panel warning lamp flashes.
- No lock-up function.
- No adaption of the gear slippage times at high altitude (High Altitude Compensation).
- No reduction of system pressure when shifting, making shifting harsher.
- No reduction of system pressure when moving the gear selector between positions P-R, N-R and N-D which causes harsh gear meshing.
- No torque limiting request to engine control module (ECM) when shifting.

NOTE: The Motronic 4.4 engine control module posts a diagnostic trouble code when the transmission sends a malfunction indicator lamp (MIL) request. Erase this diagnostic trouble code in the Motronic engine control module when the transmission fault has been repaired.

- Start fault-tracing. Signal Missing