Flow of Diagnosis

1. Verify the customer concern by operating the 2WD/4WD engagement.

Visual Inspection Chart:

2. Visually inspect for the following obvious signs of mechanical and electrical damage.
3. If the concern remains after the inspection, connect the New Generation STAR (NGS) Tester to the Data Link Connector (DLC) located beneath the instrument panel and select the vehicle to be tested from the NGS menu. If the NGS does not communicate with the vehicle:
^ check that the program card is properly installed.
^ check the connections to the vehicle.
^ check the ignition switch position.

4. If the NGS still does not communicate with the vehicle, refer to the New Generation STAR Tester manual.
5. Perform the DATA LINK DIAGNOSTIC TEST. If the NGS responds with:
^ CKT914, CKT915 or CKT70 = ALL ECUS NO RESP/NOT EQUIP, refer to Module Communications Network.
^ NO RESP/NOT EQUIP for GEM, go to Pinpoint Test E.E: No Communication WIth Generic Electronic Module

^ NOTE: For vehicles built prior to February 5, 1998, the following criteria must be met when performing the GEM On-Demand Self-Test: headlamps and parklamps must be off and the power windows must be completely up. Failure to meet this criteria will result in DTCs B 1577 and B2357 being set. For vehicles built after February 5, 1998, the following criteria must be met when performing the GEM On-Demand Self-Test: headlamps and parklamps must be on. Failure to meet this criteria will result in DTC B1575 being set.

SYSTEM PASSED, retrieve and record the continuous Diagnostic Trouble Codes (DTCs), erase the continuous DTCs and perform self-test diagnostics for the GEM.
6. If the DTCs retrieved are related to the concern, go to the GEM Diagnostic Trouble Code (DTC) Index to continue diagnostics.GEM Diagnostic Trouble Code (DTC) Index
7. If no DTCs related to the concern are retrieved, proceed to Symptom Chart to continue diagnostics.Electronic Shift on the Fly (ESOF)