Trouble Code Conditions

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

CONDITION
System pressure solenoid STH controls system pressure in the transmission. The solenoid is controlled by an amplifier in the transmission control module (TCM) output. The transmission control module (TCM) uses the amplifier to control the current to the solenoid. A low amperage provides a high system pressure and a high amperage (approx. 1A) provides a low system pressure. This amperage is primarily affected by throttle position. Diagnostic trouble code (DTC) AT-132 is posted if the TCM registers that the amperage in the TCM circuit is too high. Solenoid STH cannot control system pressure.

SUBSTITUTE VALUE
The TCM limp-home program has been initiated.

POSSIBLE SOURCE
Defective control module.





FAULT SYMPTOM(S)
- The combined instrument panel warning lamp flashes.
- Deterioration in performance because the TCM prevents activation of the solenoids, this stops gear-shifting.
- The transmission operates only in 3rd gear in positions 3 and L, 4th gear in position D and reverse in position R.
- Shifting can only be carried out manually between 3rd, 4th, and reverse gear.
- No system pressure solenoid STH control resulting in constant maximum system pressure leading to harsher shifting and gear meshing.
- No lock-up function.

NOTE:
- The Motronic 4.4 engine control module (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 Short Circuit In STH Amplifier Circuit. Short Circuit In STH Amplifier