intermittent flashing SES light

[ds8]

Occasionally while letting my '04 GMC Envoy coast (4.2L, 2wd), I will see the SES light flash on and off one time very quickly. If I call OnStar or visit the dealership, they do not find an error code present in the controller's memory. The dealership thought the ignition switch might be the problem, but the problem has persisted after having a new ignition switch installed. Any ideas on what might cause this and how to fix it?

 

Dave Schedgick

[GM-Tech]

That's not a problem I've ever heard of. THe ideal situation would be to capture a snapshot of the PCM data when this occurs. Since it's intermittent, that might be difficult to do.

 

You might want to ask your dealership if they're willing to put the VDR (Vehicle Data Recorder) in your vehicle. This is a portable device that gets a snapshot of data when you press a button (or if a DTC sets). You can record up to 4 events. It's designed specifically to give a customer for these intermitten problems.