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View Full Version : 2016 C7.5 RS6 Performance - Critical Electrical Issue Please Help!



slickhillsy
05-22-2023, 05:52 AM
Hi all…

New to the forum, unfortunately I have a seemingly critical and baffling issue with my 2016 C7.5 RS6 Performance and thought I’d try and tap some knowledge and insights here.

In summary, my car has developed an electrical fault that completely disables the car. When driving under normal conditions the car just dies, immediately, as if unplugged from the mains. Oddly, the only thing remaining live are rear lights and minimal MMI. Often the dash freezes with the speedo and rev counter fixed at the point the car died. To fix the issue it’s a disconnect the battery, leave for at least an hour and try again with same results.

The car is currently with my local specialist for just over 2 months (QST in Haywards Heath) and they have completed the following work…

- Replace the 2 relays.
- Replaced the Tyre Pressure Monitor sensors.
- Replaced the 2 body control sensors.
- Battery holds a good charge.

Without any success. QST are doing all they can but are beginning to run out of ideas so thought I’d see if I could help by expanding the thinking here.

Has anyone experienced anything same similar they could share? Any feedback is gratefully appreciated.

Many thanks – Mark.

Audibot
05-22-2023, 06:38 AM
If you have a scan of the car for error codes (VCDS is best), that would help most.

Audisthesia
05-22-2023, 07:06 AM
Shooting in the dark without a full scan

slickhillsy
05-22-2023, 07:54 AM
Thanks both. Yes had full scans and nothing showing as an issue (once all the systems are restored)

Alabama
05-22-2023, 05:48 PM
Thanks both. Yes had full scans and nothing showing as an issue (once all the systems are restored)

Small chance but easy to try. As noted in other AZ threads, these cars are very sensitive to voltage variations. A seven year old battery may still hold a charge but not be able to provide sufficiently consistent voltage. Maybe try a new battery. Hard to imagine that scanning immediately after the car "dies" has nothing showing as an issue.

Audisthesia
05-23-2023, 06:32 AM
Yeah, however if his battery was getting low, it would absolutely be throwing codes in vcds