Checking the automatic transmission torque converter lock-up valve
Materials:
* OBD2 scanner
* Multimeter with resistance measurement function
* Container for automatic transmission fluid
* Tool set
Procedure:
1. Diagnostics using OBD2 scanner:
* Connect the scanner to the vehicle’s diagnostic port.
* Scan for trouble codes related to the torque converter lock-up valve.
2. Physical check of the valve:
* Disconnect the hose from the valve to the vacuum pump.
* Check the vacuum hose for cracks or damage.
3. Checking vacuum pressure:
*Connect the vacuum gauge to the vacuum hose.
* Start the engine and let it run.
* Check the pressure gauge readings; they must be within specification (refer to repair manual).
4. Checking the electrical resistance of the solenoid:
* Disconnect the electrical connector from the torque converter lock-up valve solenoid.
*Set your multimeter to measure resistance in Ohms.
* Connect the multimeter leads to the solenoid connector pins.
* The resistance must be within the specification given in the repair manual.
5. Checking the functionality of the solenoid:
* Reconnect the electrical connector to the solenoid.
* Start the engine and shift into gear.
* Shift quickly into another gear.
*If you hear a knocking or thumping sound when shifting gears, this may indicate a bad solenoid.
6. Checking the tightness of the valve body:
* Remove the valve body from the transmission.
* Install the transmission clamp to drain all automatic transmission fluid.
* Inspect the valve body for cracks, damage or leaks.
* Replace valve body if necessary.
7. Replacing the torque converter lock-up valve:
* If the valve is defective, replace it.
* Install the new valve into the body.
* Reinstall the valve body onto the transmission.
* Connect the vacuum hose and electrical connector.
8. Resetting automatic transmission adaptations:
* After replacing the valve, reset the automatic transmission adaptations using an OBD2 scanner or following the procedure specified in the repair manual.