This bulletin is being issued to provide dealer service personnel with information regarding aftermarket devices connected to the Diagnostic Link Connector (DLC) and the impact to OnStar(R) diagnostic probes and Vehicle Diagnostic e-mails.Ĭertain aftermarket devices, when connected to the Diagnostic Link Connector, such as, but not limited to, Scan Tools, Trip Computers, Fuel Economy Analyzers and Insurance Tracking Devices, interfere with OnStar's ability to perform a diagnostic probe when requested (via a blue button call) by a subscriber. These devices also prohibit the ability to gather diagnostic and tire pressure data for a subscriber's scheduled OnStar(R) Vehicle Diagnostic (OVD) e-mail. Subject: Information on Aftermarket Device Interference with OnStar(R) Diagnostic Services Emergency Contact Module: Technical Service Bulletins OnStar(R) - Aftermarket Device Interference Information