P0743

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

Solenoid Valve System Circuit (Part 1):

Solenoid Valve System Circuit (Part 2):

DESCRIPTIONS OF MONITOR METHODS
^ During 1st driving or 2-6th lock-up operation, an abnormal value equivalent to open or short circuit is detected in the solenoid control current for 5 seconds.

MONITOR EXECUTION
^ Continuous

MONITOR EXECUTION CONDITIONS (OTHER MONITOR AND SENSOR)

Other Monitor (There is no temporary DTC stored in memory for the item monitored below)
^ Not applicable

Sensor (The sensor below is determined to be normal)
^ Not applicable

LOGIC FLOW CHARTS (Monitor Sequence):

DTC SET CONDITIONS
Check Conditions
^ Manual mode: 1st.
^ Shift stage: 2nd to 6th.
^ Lock-up: engaged.

Judgement Criteria
^ Ground short judgment: abnormal. (5 seconds)

Check Conditions
^ Manual mode: 1st.
^ Shift stage: 2nd to 6th.
^ Lock-up: engaged.
^ Ground short judgment: normal.

Judgement Criteria
^ Open short judgment: abnormal. (5 seconds)

OBD-II DRIVE CYCLE PATTERN
Start the engine, and keep the vehicle stopped in "P" range for 5 seconds.

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.
^ 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.
Solenoid Valve Check
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.