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Does anybody know what could be the cause of this error?
I sometimes get this fault coming up now that the car is remapped.

17963 - Charge Pressure: Maximum Limit Exceeded
P1555 - 35-10 - - - Intermittent

I have checked the usual vacuum hoses and they seem OK
and I have recently replaced the DV's to late spec.
TBB seems to be ok too.
N75 is the original one.

Any ideas?

Many Thanks.

Who re-mapped it ?

My guess is you have either spiked through 1.5 bar or have deviated spec from actual too much.
Try logging block 115 and 003. AMD remap?

This is the fault I had when my TBB failed.

Dealer said it was because the turbos were over-spinning attempting to maintain the requested pressure, then the split was closing intermittently, causing a boost spike and the DTC.

I had this error on my old S4 for about 2 years and never got to the bottom of it. The only thing i could think of was that the map was supplying too much boost and hitting the limit.

Yup I had the same prob with my AMD remap. Every three or so months I'd get a limp mode which would reset itself upon switching off the ignition and switching back on. Sometimes I didn't even have to switch the ignition off. I was convinced the hyperboost DVs were at fault. I had Star Perfromance check it out twice but Jim never found a prob he often wondered if the limit for recording this was to close to the tempory overboost AMD set in their map. I never got round to fitting standard Bosch DVs or fitting the APR boost gauge I bought to register what was actually happening. The thing with mine was it occured so infrequently I was never motivated enough to get off my arse to get to the bottom it.

I think Dippy had a similar prob.

Thanks for the pointers guys.
Its had a remap done at AMD a few weeks back although Kim was surprised they didnt change the TBB and F hose as a matter of course.
It does spike a bit high on overboost. On the way back from AMD I managed 18psi but its been touching 20psi lately.

Looks like I'll have to change the TBB and F just to be safe.

My limp mode was due to a cat temperature sensor fault. I have never had any other DTC relating to boost problems. This may actually be because I have an APR bipipe instead of a TBB.

Based on what DavidT reported, it looks like the TBB could be at fault. Under full boost the TBB does ''balloon" out and this flex can eventually cause a tear. In theory I could imagine that because of the change in TBB volume, there could be unexpected pressure changes which under certain circumstances could trigger an overboost detection. Just theory but maybe that could explain Simon's experiences.

AmD have a 'laid-back' attitude to TBBs. When I had my stage 1 remap done, I asked Scott to fit a Samco TBB. He claimed that the Samco unit was inadequate at retaining the boost sensor and so he had use the AmD failsafe method on my car. This was a new OEM TBB with a tie-wrap around it. Whilst I could see that the tie-wrap would reduce some of the "ballooning", I was unimpressed. So I fitted the APR bipipe. When the guys at AmD saw the bipipe they (including Scott) were very impressed. But not enough to do anything about it...

N.B. 18psi peaks may be expected when you really try to get max boost. 20psi is looking a bit too high.

What boost are you normally seeing with your remap Dippy?

around 1.3 bar

I don't have an AMD remap, but have had a boost guage fitted on/off for months at a time, so can advise what my boost is doing with an APR chip.

I regularly see 18psi, but this soon drops to a consistent 16psi (was 14psi with std IC's) - I have never seen 20psi, but this could be down to the gauge (or did you get the readings from vag-com?).

I would ask AMD what the max boost spike should be for their remap. Do you hear any unusual noises coming from your car i.e. wooshing?

Do we know if anyone has managed to capture this "ballooning" on video...

It would be interesting to do to see just how much a good TBB ballons, and maybe a ripped one.....

Now who's brave enough to strap there DV camera onto there engine....

Maybe someone has looked at this while there car is on a rolling road? Anyone?

Do you hear any unusual noises coming from your car i.e. wooshing?

That's a very good point. The whoosing (leaking air) sound was present when my TBB split, along with the DTC.

No I dont have any whooshing noises other than the normal whistling of the turbo...

But I thought if I had an air leak, I wouldn't see the boost go as high as normal as it would be leaking out
before getting to the inlet manifold?

My boost readings are taken from the inlet manifold; I have T'ed my autometer boost guage from the vacuum line going to the fuel pressure regulator.

I have spoken to AMD a few times but their knowledge seems to be limited to "just bring the car in"
Scott is the only who would seem to know but he's never available on the phone.

Only if it was a big leak, and then you would have low boost problems (and need new turbos soon).

Based on what I understand about the engine (yes that's a caveat), if it is a small leak (typical for a torn TBB), then the turbos then just work a bit harder to meet demanded pressure. Then when you re-open the throttle after a gearchange, a boost spike can occur as the DVs close. Because the turbos had been spinning that bit faster to compensate for the air leak, they can make the spike a bit bigger, causing your DTC.

However you say your TBB is OK - I assume you have removed it and checked?

In your position I wouldn't hang about. AmD are right, they cannot really diagnose over the phone. You should take it in for them to take a look.

P.S. I've never seen the TBB ballooning, but people who have (e.g. Scott) described it to me.