Forum Discussion
attached device may be preventing your vehicle's diagnostic test
I have been receiving from on-star "an attached device may be preventing your vehicle's diagnostic test from completing. Unplug any devices from the diagnostic port and try again later." Car w...
TravisP23 have you found any resolution to your issue? We are still waiting. Unbelievable.
We're sorry to hear about this ongoing error you're experiencing. Our team would like the opportunity to look into things further on our end and see how we may assist. To get started, please send us an email with these details to socialmedia@gm.com with "ATTN: OnStar Community/dbwhitsitt" in the subject line. We'll keep an eye out for your message.