Torque converter clutch solenoid circuit

The shift solenoid valve dsl is turned on and off by signals from the ecm to control the hydraulic pressure acting on the lock-up relay valve, which then controls operation of the lock-up clutch.

Fail-safe function: if the ecm detects a malfunction, it turns the shift solenoid valve dsl off.

Torque converter lock-up is controlled by the ecm based on engine rpm, engine load, engine temperature, vehicle speed, transmission temperature, and shift position selection. The ecm determines the lock-up status of the torque converter by comparing the engine rpm (ne) to the input rpm (nt). The ecm calculates the actual transmission gear by comparing the input rpm (nt) to the output rpm (sp2).

When conditions are appropriate, the ecm requests "lock-up" by applying control voltage to the shift solenoid valve dsl. When the shift solenoid valve dsl is opened, the shift solenoid valve dsl applies pressure to the lock-up relay valve and locks the torque converter clutch. If the ecm detects an open or short in the shift solenoid valve dsl circuit, the ecm interprets this as a fault in the shift solenoid valve dsl or its circuit. The ecm will illuminate the mil and store a dtc.

Refer to dtc p0741 (see page ax-62).

1. Inspect transmission wire (shift solenoid valve dsl)

1. 1
   Disconnect the b27 wire connector.
2. 2
   Measure the resistance of the transmission wire.

Standard resistance

2. Check wire harness (transmission wire - ecm)

1. 1
   Disconnect the b30 ecm connector.
2. 2
   Measure the resistance of the wire harness side connector.

Standard resistance

3. Inspect shift solenoid valve dsl

1. 1
   Remove the shift solenoid valve dsl.
2. 2
   Measure the resistance between the solenoid valve terminal and solenoid valve body.

Standard resistance: 11 to 13 at 20°c (68°f)

3. Connect the battery's positive (+) lead to the terminal of the solenoid valve connector, and the negative (-) lead to the solenoid body. Then check that the valve moves and makes an operating noise.