Front assist & ACC unavailable

[Mick]

I am on my way back from Skye. My ACC has been working fine but has now started throwing up the above errors and the cruise control is inactive.

The roads were very bumpy. There are no errors shown on the Carista.

Is there anyway or process to get it sorted or is it a dealer job.

I did take out the £38 a month extended warranty so I’m thinking it is covered.

Edit: I just found this.

 

[Loz]

That’s a lot of faults to be all real, just clear them and see what comes back and see if your ACC starts working.

 

[mmi]

Loosened up radar sensor? - because of the code 1541.
To decode the fault codes - strip the leading zero padded by Carista.

VCDS And Carista Fault Codes

Any ideas anyone on fault code 16399? I got a flashing glow plug symbol just as I got on the ferry to France. Then an engine one when we disembarked...

www.t6forum.com

 

[Pauly]

Ice on the front radar or traction/ABS activation on bumpy road would kill cruise control

 

[Salty Spuds]

Ice on the front radar or traction/ABS activation on bumpy road would kill cruise control

I’ve had a couple of problems on the way to the Alps with ice buildup. Also, and this is a bizarre one, when towing a trailer, a bulb failure on the trailer will cause the ACC to lockout.

 

[Mick]

It just came back and started working.

@Loz I have no fault codes to clear in the Carista just in that data drop.

It’s now happened a few times and last time the dealer said they couldn’t find anything.

 

[Mick]

Ice on the front radar or traction/ABS activation on bumpy road would kill cruise control

Yep I got that coming off a glacier in Austria. Last month coming from Spain I had salt caking the sensor.

 

[Robert]

Ice on the front radar ...

Ice would build up only if the radar internal heater fails.
See below.

My radar heater also works perfectly.
I got a chance to verify this over a very long drive this winter.
It didn't get affected/blinded by the snow nor the ice even once.
View attachment 139666
Only 7E0 radar (T6 variant) of a 7N0 radar family is equipped with a heater.
Caddy, Sharan, etc. don't get this amazing functionality. Credit goes to @dnoermann

 

[Mick]

Nightmare drive back. The flashing coil light came on. Then it went off. The ACC failed again and then came back. Then the flashing coil came back on and stayed on. 20 miles later the engine light came in when I was 15 miles from home. So I may have an air leak and the DPF needs regeneration from Carista codes. Probably caused by the air leak. Booked it in to Listers but they’re booking out to March FFS. But I have no plans for using it at the mo so I’ll drop it off and they’ll fit it in for diagnostic.

 

[stu3467]

My car throws this fault every time i go out in crap weather tends to be dirt and salt on the sensors, I imagine you have tried cleaning them if so just ignore me

 

[Mick]

My car throws this fault every time i go out in crap weather tends to be dirt and salt on the sensors, I imagine you have tried cleaning them if so just ignore me

Yep I was in some seriously crap weather in Austria and Spain. Snow etc. trip to Skye was a salty nightmare.

But I now have bigger issues to sort with the air leak error code.

Hey Ho moneypits R Us

 

[stefan8868]

Mine had the ACC fault and I lost cruise/ anti collision. VW quoted AUD1,500 - 2000 to rectify and couldn’t fix for 2-3 months due to effort to recalibrate. I had a look and there was nothing obviously bent or broken. Pulled out front sensor and reassembled without adjusting. Fault disappeared after about 75km.

Still cranky about treatment by VW under warranty, but relieved problem has gone away.

 

[prosparx]

Nightmare drive back. The flashing coil light came on. Then it went off. The ACC failed again and then came back. Then the flashing coil came back on and stayed on. 20 miles later the engine light came in when I was 15 miles from home. So I may have an air leak and the DPF needs regeneration from Carista codes. Probably caused by the air leak. Booked it in to Listers but they’re booking out to March FFS. But I have no plans for using it at the mo so I’ll drop it off and they’ll fit it in for diagnostic.

I had exactly the same symptoms returning from Montgenevre (Alt: 1860 - 2700m). Coil light, engine light and lost ACC. The warning lights went off when I reached the Eurostar, however, the ACC remains faulted. Did you get your ACC diagnosed and repaired? If so, can you share the fix?

 

[Mick]

I had exactly the same symptoms returning from Montgenevre (Alt: 1860 - 2700m). Coil light, engine light and lost ACC. The warning lights went off when I reached the Eurostar, however, the ACC remains faulted. Did you get your ACC diagnosed and repaired? If so, can you share the fix?

 

[Mick]

ACC was a no fault found with Listers and it’s never be appeared. I did have a DPF issue which was caused by a blown hose and once that was fixed no more issues.