Trouble Code Conditions

Special Tools:
- 981 3190
- 998 8686

Trouble Code Conditions
- 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 with vehicle speed. The transmission control module uses this comparison to calculate gear-shift timing. The transmission speed and vehicle speed data are also utilized in modulating system pressure, lock-up function control and in torque limiting. The result is smooth gear-shifting. Diagnostic trouble code (DTC) AT-311 is stored if the transmission control module does not register this signal when vehicle speed exceeds 25 km/h (16 mph).

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

Possible source(s)
- Open-circuit in the signal cable (+) or signal cable (-).
- Short-circuit to ground or voltage in signal cable (+) or signal cable (-).
- Short-circuit between the signal cable (+) and signal cable (-).
- Defective transmission speed sensor.
- 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