Retrieving Diagnostic Trouble Codes
- Locate Data Link Connector (DLC) near right side of steering column. Install jumper wire between diagnostic pigtail (Orange wire at DLC terminal No. 13) and ground.
- Turn ignition on Observe 4WD elector switch status lamps. After approximately 3 seconds, status lamp should flash if a DTC is present. If more than one code is present, the second code will flash after a 3 second delay. All transfer case DTCs are single digit numbers. See Fig 1.
- Write down all DTCs. After retrieving DTCs. Clear TCCU memory and repeat procedure. See CLEARING DIAGNOSTIC TROUBLE CODES . If DTCs return, perform appropriate test. See DIAGNOSTIC CHARTS under DIAGNOSTIC TESTING .
Courtesy of GENERAL MOTORS CORP.