Trouble Code Conditions

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

CONDITION
Torque from the engine is reduced in some gear changes to allow smoother shifting and to minimize transmission wear. The torque limiting process is controlled by signals (TC1/TC2) sent from the Transmission Control Module (TCM) to the Engine Control Module (ECM). An acknowledgement signal is sent from ECM to the TCM. This signal only indicates that the ECM has received a torque limiting request from the TCM. Diagnostic Trouble Code (DTC) AT-245 is posted if the TCM fails to register an acknowledgement signal after a torque limiting request.

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

POSSIBLE SOURCE
- Open-circuit in signal cables TC1, TC2 and TCM
- Short-circuit to ground or supply voltage in signal cables TC1, TC2 and TCM
- 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 ECM when shifting

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