Diagnostic trouble code (DTC) information

Condition 

Fig 1: Identifying Line Pressure Solenoid, STH

Courtesy of VOLVO CARS OF NORTH AMERICA.

Line pressure solenoid STH regulates the line pressure in the transmission. The solenoid is controlled by a power stage in the control module output. The transmission control module (TCM) uses the power stage to control the current to the solenoid. A low amperage results in a high line pressure. A high amperage (approximately 1 A) gives a low line pressure. The amperage is primarily affected by the throttle position. Diagnostic trouble code (DTC) TCM-000F is stored if the control module registers that there is no current in the circuit for solenoid STH. Solenoid STH cannot then control the line pressure.

Substitute Value 

• The control module "Limp Home" program has been initiated.

Possible Source 

• Contact resistance in the terminals.
• Open-circuit in the control signal cable or the signal cable.
• Defective solenoid STH.

Fault symptom[s] 

• General orange warning lamp lit.
• Malfunction indicator lamp (MIL) lit.
• No lock-up function.
• Harsh gear shifting.

HINT: Harsh gear shifting can be caused by: 

• No torque limiting request to engine control module (ECM) when shifting.
• No line pressure solenoid STH control. This results in constant maximum line pressure.