XC70 L5-2.5L Turbo VIN 59 B5254T2 (2003)
Control Module: Description and Operation
Design
Design
Control module
The transmission control module (TCM) is positioned in an air cooled plastic box in the engine compartment together with the engine control module
(ECM).
Shift solenoids S1, S2, S3, S4 and S5
The shift solenoids S1, S2, S3, S4 and S5 are positioned in the valve body in the transmission control system, which is mounted on the front edge of
the transmission. The shift solenoids (on/off type), consist of an electrical coil which controls a hydraulic valve. The solenoids are supplied with 12 V
via the transmission control module (TCM) and grounded in the control system. The shift solenoids control shifting and the transmission control
module (TCM) determines which gear is to be used by activating them in different patterns. There is a diagnostic for the shift solenoids.
Lock-up solenoid, SLU
The lock-up solenoid, SLU is in the transmission control system, which is mounted on the front edge of the transmission. The lock-up solenoid
consists of an electrical coil which controls a hydraulic valve. The solenoid is controlled by pulse width modulation (PWM) voltage and is grounded
via the transmission control module (TCM). The solenoid controls lock-up engagement of the torque converter. Engagement occurs through solenoid
pulsing which provides a soft lock-up engagement function. The solenoid allows the torque converter to work in one of three modes:
-
Open
-
Controlled slipping
-
Locked.
The hydraulic function of the solenoid is linear. There is a diagnostic for the lock-up solenoid.
