850 T5R momentary cut out under hard acceleration

[richmac]

Hi,

Hopefully the BCS/ TCV from chap who's had this issue will resolve the it but will certainly help us with diagnostics if it doesn't. My only question for now is whether the car re-mapped?

I suspect the ABS issue is mutually exclusive. The older TRACS system used in the 850 and P1 V70 only uses the ABS sytem in operation. It sounds like you're beyond the speed threshold when your problem occurs. That the problem is still there with TRACS off logically eliminates it also. I've attached a document that should be of interest. Your DTC is specifically adressed on p12.

Did the the Temp Sensor code come back? Unlikely to be the cause but it always surprises me how many things this affects.

Best regards,

Rich.

[PSJVTHEBEST]

Hi Rich,
Not re-mapped - very standard.
The temp sensor code did not come back...thankfully. I now just have the 424 (Pressure switch for TRACS, faulty or short circuit) remaining.
The TCV should be here tomorrow so I will fit it as soon as I can and report back.
Thanks for your input.
Pete

[Luxobarge]

I'm with Richmac on this. To the best of my knowledge, on these cars TRACS works by applying braking to the spinning wheel via the ABS system, not cutting power to the engine. So I suspect that your two problems are not actually related, I'm pretty confident that the TCV or something related to it is causing your engine to cut out, this absolutely ties in with the symptoms and there aren't many things that can cause the engine to cut without leaving a relevant code, and none that I can think of that would only happen under hard acceleration apart from TCV as described.

An interesting one - keep us updated!

Cheers

[PSJVTHEBEST]

I will definitely keep you updated! Thanks for your input.
I have attached a couple of photos relating to the earlier work done on the engine just for forum members information. One shows one of the vacuum hoses pre replacement and another the inlet port - not sure how healthy that looks.
Pete

[Baffler]

Originally Posted by Luxobarge

To the best of my knowledge, on these cars TRACS works by applying braking to the spinning wheel via the ABS system, not cutting power to the engine.

Interesting, Luxo, is this applicable to just Motronic 4.3 / 4.4 or also the later ME7 P80 through to 2005?

It's just that on my old '98 V40 T4 I was of the belief that the DTCS was controlled by cutting the fuel supply so assumed the X40 system stemmed from the P80 platform.

[Luxobarge]

Originally Posted by Baffler

Interesting, Luxo, is this applicable to just Motronic 4.3 / 4.4 or also the later ME7 P80 through to 2005?

It's just that on my old '98 V40 T4 I was of the belief that the DTCS was controlled by cutting the fuel supply so assumed the X40 system stemmed from the P80 platform.

On these cars I don't think that the TRACS is connected or related to any particular engine management system, it's just a basic system within the ABS control module - and therefore not particularly effective in my view. Certainly when I've had a spinning wheel under acceleration it's just applied braking to the spinning wheel and never cut power. Also a system that does cut power should do it more progressively than you are experiencing, and this is only really possible with electronic throttle, which both my car and all the 850s doesn't have. Although the later V70 cars do, they still share the same old style of ABS controller so I very much doubt that the TRACS is any more sophisticated.

I do stand to be corrected on all of the above though, others on here might now a more definitive answer.

Cheers

[PSJVTHEBEST]

Dancake has kindly sent me a TCV to try but I have a poorly dog here at the moment who is taking up all my time so please don't think I have left this thread hanging. I will definitely fit it as soon as I can and revert. Thanks to Baffler and Luxobarge for their latest contributions.