A recent diagnostic session on a 2008 Chevrolet Tahoe presented communication problems when using an Autel Maxisys scan tool. The vehicle, received from a collision shop addressing an air suspension issue, exhibited unusual behavior during the scan. The Autel failed to automatically detect the VIN, requiring manual entry. Subsequent system scans failed to communicate with the Engine Control Module (ECM) and triggered a U0100 code (Lost Communication with ECM) on most high-speed bus modules. Furthermore, the vehicle’s gauges displayed erratic behavior only when the Autel was connected to the Data Link Connector (DLC).
Disconnecting the Autel and utilizing a Snap-on Zeus scan tool yielded different results. The Zeus successfully communicated with the ECM, stabilized the gauges, and changed all communication codes from current to historical. Reconnecting the Autel reproduced the initial communication errors and gauge malfunctions. Bus captures were taken during both Autel and Zeus scans, revealing unusual bus activity during the Autel scan.
Prior to this incident, the same Autel Maxisys successfully diagnosed a 2008 Tahoe Hybrid without any communication issues. The Autel in question is updated to the latest software version. The lack of similar reported issues from the collision shop, combined with the problem’s exclusive manifestation when the Autel is connected, suggests a potential compatibility issue between the Autel and this specific vehicle. Further testing on similar GM models of the same era is necessary to confirm this hypothesis.
