Troubleshooting

DTC P0748 PRESSURE CONTROL SOLENOID "A" ELECTRICAL

CIRCUIT DESCRIPTION

DTC Detecting Condition (1MZ-FE):

Shifting from 1st to O/D is performed in combination with ON and OFF operation of the shift solenoid valves SL1 and SL2 which is controlled by the ECM. If an open or short circuit occurs in either of the shift solenoid valves, the ECM controls the remaining normal shift solenoid valve to allow the vehicle to be operated smoothly (Fail safe function).










Fail safe function:
If either of the shift solenoid valve circuits develops an open or short, the ECM turns the other shift solenoid ON and OFF in order to shift into the gear positions shown in the table. The ECM also turns the shift solenoid valve SL OFF at the same time. If both solenoids malfunction, hydraulic control cannot be performed electronically, and so it must be done manually.

Manual shifting as shown in the following table must be done (In case of a short circuit, the ECM stops sending the current to the short circuit solenoid).

Wiring Diagram:

Step 1:

Step 2:

Step 3:

Step 4 - 5:

INSPECTION PROCEDURE