Circuit Description

The shift solenoid valve SL is turned ON and OFF by signals from the ECM to control the hydraulic pressure in the lock-up relay valve, which then controls the operation of the lock-up clutch. Fail-safe function:

• If the ECM detects a malfunction, it turns the shift solenoid valve SL OFF.
• The system cannot control the lock-up relay valve. (No relation to 3-4 shift control)

Fig 1: Torque Converter Clutch Solenoid Circuit Chart

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