Brake warning light,engine cuts

[Graham J]

Weird one here....70mph on motorway and it throws a brake warning light...couple of beeps from the dash and the engine cuts out..

Left it for a couple of minutes and it started right as rain again.

Its now done this around half a dozen times ranging from two minutes driving to two hours without cooking out.

Only code that came up was a low pressure at the turbo boost regulator and was told it could have been a while ago the code registered but still doesn't explain the sudden engine cut out at random times....

Anyone had a similar experience with the 8P 2.0 Tdi...?

[Magnet]

Hello Graham,

Sorry to appear unhelpful, but it really doesn’t matter if anyone else has suffered this dangerous occurrence - you have - and even if they have, it doesn’t mean that their cause will be the same as yours.

Please get this booked in to a (diesel?) specialist without delay, before you get involved in/cause a serious accident on a motorway. 
Apologies if this comes over as dictatorial, but your are responsible for your own and others safety. 
Kind regards,

Gareth. 

[Magnet]

Hello Graham,

We notice you have returned to the forum to read the response, and wonder whether you agree or disagree with the advice given.

Kind regards,

Gareth. 

[cliffcoggin]

15 hours ago, Graham J said:

Anyone had a similar experience with the 8P 2.0 Tdi...?

Not an identical experience but close enough that it may be relevent. Occasionally mine (also a 2 litre diesel from 2007) would simultaneously show a brake warning light, lose cruise control, lose air con, lose radio presets, and go into limp mode. A few minutes rest restored normal operation. The cause was recognised by a local VAG specialist, who ignored all the false error codes, as a defective battery.

Have you had any other strange electrical faults? Was the engine slow to crank over when starting last winter? How old is your battery?

[Graham J]

11 hours ago, cliffcoggin said:

Not an identical experience but close enough that it may be relevent. Occasionally mine (also a 2 litre diesel from 2007) would simultaneously show a brake warning light, lose cruise control, lose air con, lose radio presets, and go into limp mode. A few minutes rest restored normal operation. The cause was recognised by a local VAG specialist, who ignored all the false error codes, as a defective battery.

Have you had any other strange electrical faults? Was the engine slow to crank over when starting last winter? How old is your battery?

First time I've had a problem other than a DPF light last year..that rectified itself after a good run..Battery is only two years old and cranks well..

[Graham J]

15 hours ago, Magnet said:

Hello Graham,

We notice you have returned to the forum to read the response, and wonder whether you agree or disagree with the advice given.

Kind regards,

Gareth. 

Thank you, still looking for advice...

[cliffcoggin]

10 hours ago, Graham J said:

First time I've had a problem other than a DPF light last year..that rectified itself after a good run..Battery is only two years old and cranks well..

Nevertheless it's worth getting it tested.

[Graham J]

On 8/22/2022 at 9:49 AM, cliffcoggin said:

Nevertheless it's worth getting it tested.

Three different places to date have put a code reader on it and still scratching their heads as to a problem...no codes showing at all now?..

I disconnected the battery for a while and when reconnected I've gained a power steering and ESC dash light,which may or may not dissapear on the next drive....keep looking 👀

 

[Magnet]

Hello Graham,

OK battery may be only 2 years old, but I wouldn’t ignore Clifford’s experience, and would suggest that you have a ‘sophisticated’ ( or whatever word you choose) test carried out on your battery - if only to eliminate it from the equation. This test would include cold cranking amps and other parameters, and not simply % efficiency. Not sure if your car is too old to be fitted with a battery condition monitor, but…Also worth getting the alternator output checked at the same time. 

Kind regards,

Gareth.

[cliffcoggin]

Forget about code readers and computer diagnostics. Get the battery tested by a deep discharge method which puts a heavy electrical load on it and will reveal problems that a normal volt meter will not detect.

[Graham J]

On 8/20/2022 at 7:37 PM, Graham J said:

Weird one here....70mph on motorway and it throws a brake warning light...couple of beeps from the dash and the engine cuts out..

Left it for a couple of minutes and it started right as rain again.

Its now done this around half a dozen times ranging from two minutes driving to two hours without cooking out.

Only code that came up was a low pressure at the turbo boost regulator and was told it could have been a while ago the code registered but still doesn't explain the sudden engine cut out at random times....

Anyone had a similar experience with the 8P 2.0 Tdi...?

Problem solved swapping out left hand 460 relay under dash👍

[Magnet]

Thanks Graham,

What does this relay service? 
Kind regards,

Gareth. 

[Graham J]

1 hour ago, Magnet said:

Thanks Graham,

What does this relay service? 
Kind regards,

Gareth. 

Its responsible for supplying power to the entire motor's electrical systems afaik?

[Magnet]

OK, 

‘…..entire electrical systems …’. ! Sounds one heck of a responsibility to me. 

[Graham J]

23 minutes ago, Magnet said:

OK, 

‘…..entire electrical systems …’. ! Sounds one heck of a responsibility to me. 

Not something your engines entire electrical system can always re-lay on 🤣