PRE-RELEASE
DTC P0743 TORQUE CONVERTER CLUTCH CIRCUIT ELECTRICAL
| DTC P0743 TORQUE CONVERTER CLUTCH CIRCUIT ELECTRICAL |
DIAGNOSIS:
The output signal circuit of lock-up duty solenoid is open or shorted.
TROUBLE SYMPTOM:
No “lock-up” (after engine warm-up).
WIRING DIAGRAM:
CHECK DTC.
Do multiple DTCs appear in the on-board diagnostics test mode?
| Yes |
Go to another DTC.
| No |
CHECK HARNESS CONNECTOR BETWEEN TCM AND TRANSMISSION.
Turn the ignition switch to OFF.Disconnect the connector from TCM and transmission.
Measure the resistance of harness between TCM and transmission connector.
Connector & terminal
(B56) No. 5 — (B11) No. 12:
Is the resistance less than 1 Ω?
| Yes |
| No |
Repair the open circuit in harness between TCM and transmission connector.
CHECK HARNESS CONNECTOR BETWEEN TCM AND TRANSMISSION.
Measure the resistance of harness connector between TCM and chassis ground.Connector & terminal
(B56) No. 5 — Chassis ground:
Is the resistance more than 1 MΩ?
| Yes |
| No |
Repair the short circuit in harness between TCM and transmission connector.
CHECK LOCK-UP DUTY SOLENOID.
Measure the resistance between transmission connector receptacle’s terminals.Connector & terminal
(T4) No. 12 — No. 20:
Is the resistance 2.0 — 6.0 Ω?
| Yes |
| No |
CHECK LOCK-UP DUTY SOLENOID (IN TRANSMISSION).
Disconnect the transmission connector.Drain the ATF.
| Important | ||
|
Do not drain the ATF until it cools down. |
||
Remove the oil pan and disconnect connector from lock-up duty solenoid.
Measure the resistance between lock-up duty solenoid and transmission ground.
Connector & terminal
(AT12) No. 4 — Transmission ground:
Is the resistance 2.0 — 6.0 Ω?
| Yes |
| No |
Replace the control valve body.
CHECK HARNESS CONNECTOR BETWEEN LOCK-UP DUTY SOLENOID AND TRANSMISSION.
Measure the resistance of harness between lock-up duty solenoid and transmission connector.Connector & terminal
(T4) No. 12 — (AT12) No. 4:
Is the resistance less than 1 Ω?
| Yes |
| No |
Repair the open circuit in harness between TCM and transmission connector.
CHECK HARNESS CONNECTOR BETWEEN LOCK-UP DUTY SOLENOID AND TRANSMISSION.
Measure the resistance of harness between transmission connector and transmission ground.Connector & terminal
(T4) No. 12 — Transmission ground:
Is the resistance more than 1 MΩ?
| Yes |
Even if the POWER indicator blinks, the circuit has returned to a normal condition at this time. A temporary poor contact of the connector or harness may be the cause. Repair the harness or connector in lock-up duty solenoid and transmission.
| No |
Repair the short circuit in harness between lock-up duty solenoid and transmission connector.
