Code No.P0741: Lock-up Control Solenoid System (Stuck OFF), P0742: Lock-up Control Solenoid System (Stuck ON)

OPERATION

Solenoid closes or opens according to the signals from the A/T-ECU.
The A/T-ECU energises or deenergises solenoid, based on input signals such as accelerator pedal position sensor opening angle, inhibitor switch, etc.

DIAGNOSIS CODE SET CONDITIONS

If a status continues for 12 seconds with which the difference between the engine speed and input shaft speed is standard value or more, code No.P0741 is set.
If a status continues for 4 seconds with which the difference between the engine speed and input shaft speed is standard value or less, code No.P0742 is set.

PROBABLE CAUSES

Damaged harness wires and connectors
Malfunction of the A/T-ECU
Malfunction of solenoid valve
Malfunction of valve body assembly
Malfunction of torque converter assembly
Malfunction of transmission assembly
Malfunction of the lock-up control solenoid system (for diagnosis codes P2762, P2763, P2764)
Malfunction of the shift solenoid SB system (for diagnosis codes P0976, P0977)

DIAGNOSIS PROCEDURE

STEP 1. Solenoid check

Check the lock-up control solenoid and the shift solenoid SB (Refer to

).

Q. Is the check result normal?

	Go to Step 2.

	Replace the valve body assembly.

STEP 2. Check whether the diagnosis code is set again.

Ignition switch: "LOCK"(OFF) → "ON"
Check again if the diagnosis code is set.

Q. Is diagnosis code No.P0741, P0742 set?

	Replace the torque converter assembly or the transmission assembly.

	Intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent Malfunction ).