TCU Diagnostic Circuit Check
- Road test vehicle and leave engine running once road test is completed. Retrieve trouble codes. See RETRIEVING TROUBLE CODES
. If voltmeter needle sweeps or test light flashes, go to next step. If voltmeter or test light shows no flash reaction, go to step 4).
- If code 12 is present, turn ignition switch to the LOCK position. Disconnect transaxle harness connector. See Fig 1
. Perform the MANUAL SHIFTING TEST
. Go to next step. If any other trouble code is present, go to appropriate code test.
- If transmission does not shift correctly, see overhaul article. If transmission shifts correctly, perform procedures for the THROTTLE POSITION SENSOR CIRCUIT CHECK
. If no faults can be found, problem is intermittent, see overhaul article. If faults are found performing THROTTLE POSITION SENSOR CIRCUIT CHECK, see appropriate repair manual.
- If voltmeter or test light shows no reaction, go to step 6). If voltmeter shows full (constant) meter sweep or test light is always on, turn ignition off. Disconnect TCU 14-pin connector. See Fig 2
and Fig 3
.
- Check continuity between Green
monitor connector terminal No. 1 (MD13Pink wire) and TCU terminal No. 13 (14-pin connector). Also check for short to ground. Repair as needed. If circuit is okay, replace TCU and retest.
- Remove test light or voltmeter. Using test light, check for voltage between monitor connector (Green
connector) terminal No. 2 (Black
/White wire) and ground. If voltage is not present, repair circuit and retest. See appropriate wiring diagram in WIRING DIAGRAMS
.
- If voltage is present, inspect TCU harness connector. Repair as needed. Inspect circuits between monitor connector, DIAG connector and TCU. Repair as needed. See appropriate wiring diagram in WIRING DIAGRAMS
. If all circuits are okay, replace TCU and retest.
Courtesy of SUZUKI OF AMERICA CORP.
Courtesy of SUZUKI OF AMERICA CORP.
Courtesy of SUZUKI OF AMERICA CORP.