ACC intermittent issue..could my BFG tyres be to blame?

[Desmoben]

Anyone have issues with their ACC on T6.1’s after fitting BFG’s 245/65 r17’s.

My dash lights up with a ACC disabled, sensor restricted (or something) and my VW dealer is telling me the sensor might need realigned because of the larger rolling radio us and the van sitting higher by...an inch!

If that’s true .. how does it work if there is a heavy load in the back and the nose is pointing towards the sky???

 

[JasonW]

I would not of thought the van being higher by an inch will cause the ACC to stop working....

 

[Desmoben]

I would not of thought the van being higher by an inch will cause the ACC to stop working....

What about the larger cicumfrance of the new tyres throwing the speedo reeding out by 10% and that perhaps conflicting with whatever info the ACC /gps uses to make it think .. hold on a min -something is not right??

 

[Loz]

The alignment is quite precise so a change might throw it out if it was already borderline.

there is no gps speed, only what the wheel sensors are telling it. So as long as your tyre pressures are the same and you have reset the tyres in the mfd then it must be alignment of the sensor. I would also check the plastic surround of the sensor has not come loose.

 

[Desmoben]

Thanks Loz, I’ve it booked in with VW for them to have a look at (1st available date is 25 March!) see if they can sort it out. Now that I think about it, it threw up the error on the one journey I did before I swapped from the one 16” wheels.
Concerned that the largest wheel option on the MFD are still reading low by 6 or 7%.

 

[mark]

I had oversize tyres for 6 months with no issues at all?

 

[Desmoben]

Now, I’ve had the van up the M way 70 miles both ways. If I keep the van at 113kmph indicated ( 120kmph actual) or below the ACC works faultlessly. As soon as I put it up to 120kmph indicated or over it cuts the ACC off with “sensor impaired” message after 5 or so mins and keeps it knocked off for 5 to 10 mins when it seems to become available again.

 

[Loz]

There were 2 versions of ACC one of them only works up to a certain speed.

 

[Desmoben]

Took my van to my local mechanic before taking it back to VW and he plugged it in. The ACC error is coming up as a low voltage and unknown error.
Nothing mentioned about alignment issue. When I mentioned this to the salesman in VW he volunteered that he had heard a few people in VW mentioning the low voltage thing of late.
Possible warranty issue?

 

[Desmoben]

 

[Loz]

I suspect the CAN Bus isolating relay, or similar relay used to isolate components that can be attacked from outside when its locked.
Could also be poor earth for that module.
I would disconnect and reconnect the module as well, but it's under warranty so the dealer can do it.

 

[BigDean]

Took my van to my local mechanic before taking it back to VW and he plugged it in. The ACC error is coming up as a low voltage and unknown error.
Nothing mentioned about alignment issue. When I mentioned this to the salesman in VW he volunteered that he had heard a few people in VW mentioning the low voltage thing of late.
Possible warranty issue?

Don’t know if it’s the same issue but since @Loz helped me out with VCDS to setup my 6.1 with the BFGs, not had the ACC error once. Was happening all the time before.

 

[mmi]

Don’t know if it’s the same issue but since @Loz helped me out with VCDS to setup my 6.1 with the BFGs, not had the ACC error once. Was happening all the time before.

What size were the BFG's?
What was the factory tyre size?

 

[BigDean]

What size were the BFG's?
What was the factory tyre size?

BFG 245/65/17
Standard Highline 16” alloys.

 

[mmi]

BFG 245/65/17
Standard Highline 16” alloys.

Thank you for the contribution

ACC fault observations - including relationship with tyre size - have been gathered here:

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

 

[rtudor]

Anyone have issues with their ACC on T6.1’s after fitting BFG’s 245/65 r17’s.

My dash lights up with a ACC disabled, sensor restricted (or something) and my VW dealer is telling me the sensor might need realigned because of the larger rolling radio us and the van sitting higher by...an inch!

If that’s true .. how does it work if there is a heavy load in the back and the nose is pointing towards the sky???

Im getting same problem after fitting new 245 65 r17 all terrian tyres ACC error intermittently coming on Did you resolve the issue ?
Anyone have issues with their ACC on T6.1’s after fitting BFG’s 245/65 r17’s.

My dash lights up with a ACC disabled, sensor restricted (or something) and my VW dealer is telling me the sensor might need realigned because of the larger rolling radio us and the van sitting higher by...an inch!

If that’s true .. how does it work if there is a heavy load in the back and the nose is pointing towards the sky???

I'm getting the same issue

 

[rtudor]

Same issue here How can it be reconfigured?

 

[Samro]

From a previous thread, it was considered that this problem is prevalent on vans that started life with 16" wheels.
It seems that vehicles which arrived with 17" wheels are set up differently, making them less problematic to run with oversize wheel set up.
Have a look at this thread:

Larger Tyre options with ACC

Hi. Time to replace the boots. Has anyone fitted 275/40/20 tyres to T6.1 with ACC ? Whats the largest size tyre you can go without it throwing up a fault on the dash? Thanks in advance

www.t6forum.com

I have no idea if @paulbishop2 found a fix?

 

[rtudor]

Anyone have issues with their ACC on T6.1’s after fitting BFG’s 245/65 r17’s.

My dash lights up with a ACC disabled, sensor restricted (or something) and my VW dealer is telling me the sensor might need realigned because of the larger rolling radio us and the van sitting higher by...an inch!

If that’s true .. how does it work if there is a heavy load in the back and the nose is pointing towards the sky???

I have the same problem after changing tyres also Took it to my local dealer they just cleared it now its back
We're you able to get it reconfigured?