Prefunctional Check

Torque Converter Clutch Circuit:

NOTICE: Before using the Transaxle Test Box J 38791 (available) as described in the functional checks, the following procedure should be performed to ensure proper diagnosis and avoid replacement of good parts.

1. Check for stored diagnostic trouble codes. If diagnostic trouble codes are present, refer to applicable Diagnostic Trouble Code (DTC) charts and repair cause of DTC before performing functional checks.
2. Connect Test Box J 38791 and Harness J 38791-60:
^ Disconnect the vehicle transaxle wiring harness from the transaxle.
^ Connect the test box connectors to the vehicle harness and transaxle connectors.
^ Route the test box harness under the rear of the hood and through the driver's window. Ensure that the harness cannot contact the exhaust manifold or cooling fans, using tie straps if necessary.
^ Test box "GEAR SELECTOR" rotary switch to "NORMAL".
^ Insert the text box ground connector into the cigar lighter receptacle.

3. Observe the indicator lights on the test box with the ignition "ON," engine not running:
^ "BATTERY," "IGN," "SHIFT A," and "SHIFT B" should be "ON." Converter clutch "APPLY" and "MOD" indicators should be "OFF." (Disregard "BRAKE" "LO DISCRETE," "2-3" and "3-4" indicator lights).
^ If indicator lights do not function as described above, check all connections. If connections are good and indicators still do not work properly, find symptom being experienced and repair as indicated:
^ No lights "ON" or "IGN" light only "ON": Check connection at cigar lighter receptacle. If OK, fuse for cigar lighter or cigar lighter receptacle is faulty.
^ "BATTERY" light "ON," all others "OFF": Check 10 amp TCC fuse and repair short to ground in CKT 241 if blown. If OK, check for an open in CKT 241 or 3.
^ "IGN" light not "ON": Check for an open in CKT 241 to transaxle harness connector terminal
^ "SHIFT A" and/or "SHIFT B" light(s) not "ON": Refer to C Charts/Chart C-8B Shift Solenoid Functional Check (4T60E Transaxle). Chart C-8B Shift Solenoid Functional Check (4T60E Transaxle)

^ Converter clutch "APPLY" light "ON" all the time: Disconnect PCM blue connector and check CKT 422 for a short to ground. If OK, PCM is faulty.
^ Converter clutch "MOD" light "ON" all the time: Disconnect PCM red connector and check CKT 418 for a short to ground. If OK, PCM is faulty.

4. Proceed with functional check: For additional information, refer to Transmission Control Systems.