P0743

DTC P0743: Lock-up and Low-reverse Brake Linear Solenoid Valve System


















DESCRIPTIONS OF MONITOR METHODS

- While driving with the sport mode (1st gear) or lock-up activated (2nd to 6th gear), when open or short circuit is detected for 5 seconds

- The control current of solenoid valve is abnormally large or small.

MONITOR EXECUTION

- Sport mode: 1st gear driving

- Transmission range: D (lock-up activated)

MONITOR EXECUTION CONDITIONS (OTHER MONITOR AND SENSOR)

Other Monitor (There is no temporary DTC stored in memory for the item monitored below)

- P0731: Malfunction of the 1st gear incorrect ratio

- P0732: Malfunction of the 2nd gear incorrect ratio

- P0733: Malfunction of the 3rd gear incorrect ratio

- P0734: Malfunction of the 4th gear incorrect ratio

- P0735: Malfunction of the 5th gear incorrect ratio

- P0729: Malfunction of the 6th gear incorrect ratio

- P0741: Malfunction of the Malfunction of the Torque converter clutch system (Stuck off)
Sensor (The sensor below is determined to be normal)

- Not applicable

LOGIC FLOW CHARTS (Monitor Sequence)





DTC SET CONDITIONS

Check Conditions [Circuit continuity ground]

- Sport mode: 1st or Lock-up status: engaging (2nd to 6th).
Judgment Criteria [Circuit continuity ground]

- Lock-up and low-reverse brake linear solenoid valve actual current: more than 1.7 A (1 second)
Check Conditions [Circuit continuity open]

- Sport mode: 1st or Lock-up status: engaging (2nd to 6th).

- Lock-up and low-reverse brake linear solenoid valve actual command: more than 612 mA
Judgment Criteria [Circuit continuity open]

- Lock-up and low-reverse brake linear solenoid valve actual current: less than 190 mA. (5 seconds)

OBD-II DRIVE CYCLE PATTERN

Drive with the sport mode (1st gear) for approximately 10 seconds, and then drive with the transmission range D, throttle valve opening 50% or less, and vehicle speed 60 km/h (37.3 mph) or more for approximately 10 seconds continuously.

TROUBLESHOOTING HINTS (THE MOST LIKELY CAUSES FOR THIS CODE TO BE SET ARE:)

- Malfunction of the lock-up and low-reverse brake linear solenoid valve system circuit

- Damaged harness or connector

- Malfunction of the TCM

- Malfunction of the lock-up and low-reverse brake linear solenoid valve (valve body assembly)

DIAGNOSIS

STEP 1. Check the TCM terminal voltage.

[C-37 TCM connector (vehicle side, connected)]

Measure the voltage between the terminal No. 52 and body ground.

- Lock-up released: 0 V

- Lock-up engaged: 300 Hz

Q. Is the check result normal?

YES Go to Step 5.
NO Go to Step 2.
STEP 2. Check between the TCM connector and A/T control solenoid valve assembly connector.

Check for continuity between C-37 TCM connector and B-111 A/T control solenoid valve assembly connector.

NOTE:
Prior to the wiring harness inspection, check the intermediate connectors A-12 and repair that if necessary.

- Between C-37 terminal No. 52 and B-111 terminal No. 4: Continuity exists.

When the continuity check result is OK, check that the wiring harness is not shorted to the body and other wiring harness.

Q. Is the check result normal?

YES Go to Step 3.
NO Repair or replace the failure section.
STEP 3. Check the lock-up and low-reverse brake linear solenoid.

Refer to Testing and Inspection.

Q. Is the check result normal?

YES Go to Step 6.
NO Go to Step 4.
STEP 4. Check between the A/T control solenoid valve assembly connector and the lock-up and low-reverse brake linear solenoid valve connector.

Check for continuity between the A/T control solenoid valve assembly connector and the lock-up and low-reverse brake linear solenoid valve connector terminals.

- Between C-111 terminal No. 4 and the lock-up and low-reverse brake linear solenoid valve: Continuity exists.

Q. Is the check result satisfactory?

YES Replace the valve body assembly.
NO Repair or replace the failure section.
STEP 5. Check the TCM and A/T control solenoid valve assembly connector pin terminals and the connection status.

Q. Is the check result normal?

YES Go to Step 7.
NO Repair or replace the failure section.
STEP 6. Check the TCM and A/T control solenoid valve assembly connector pin terminals and the connection status.

Q. Is the check result normal?

YES Replace the TCM.
NO Repair or replace the failure section.
STEP 7. Erase the DTC code, and drive the vehicle for a while.

Check that the normal code is displayed.

Q. Is the check result normal?

YES The procedure is complete.
NO Return to START.