Trouble Code Conditions

SPECIAL TOOLS
Test box tool No. 981 3190, or equivalent
Volvo scan tool No. 998 8686, or equivalent

CONDITION
The Vehicle Speed Signal (VSS) comes from a sensor on the transmission. The Transmission Control Module (TCM) uses the signal to select the correct gear. The TCM also uses the transmission speed sensor signal to determine vehicle speed. Diagnostic Trouble Code (DTC) AT-232 is posted if the TCM registers that there is no VSS signal.

SUBSTITUTE VALUE
The TCM "Emergency mode II" program is initiated.

POSSIBLE SOURCE
- Open-circuit in the signal cable (+) or signal cable (-).
- Signal cable (+) or signal cable (-) short-circuited to ground, supply voltage or each other.
- Defective VSS
- 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 ECM posts a DTC when the transmission sends a Malfunction Indicator Lamp (MIL) request.
- Erase this DTC in the Motronic ECM when the transmission fault has been repaired.

TESTING PROCEDURE
- Start fault-tracing at Signal Missing. Signal Missing