[MR.]

Last week I drove back home on the autobahn. I was going across the highway doing speeds between 210 and 270 kmh, but while doing so I experienced over a period of two days time a total of four limp modes. The car went into limp mode at speeds between 210 and 270.

Today I went to my dealer asking for a read out of the error messages. The dealer needed the car for two hours to do this. I was like uh wait get me a computer and I will do the readout myself. The desk mechanic put the car on a bridge and looked underneath it and said nothing looks wrong...

I was like: and would you be able to "Get the computer, please". He walked back to his desk and started to write a report asking me to hand over the car for a two hour check with five different points they would need to walk through. I said "Leave it, I am going to a tuner".

Ended up at a local tuner, connected the computer and found the error messages! They said: Charging pressure control, plausibility pressure too high and Charging pressure control: Switch-off as consequence.

The charging pressure sensor got a value which is higher than the nominal value and so the car went into limp mode. I can easily reproduce it by doing those top speeds and keep pushing the car.

Any thoughts on this forum what this could be related to? Any input is welcome. I am collecting as much information as possible to get the best possible reply to the dealer so that they know how to fix it.

MR

[M3 Adjuster]

Originally Posted by MR.

Last week I drove back home on the autobahn. I was going across the highway doing speeds between 210 and 270 kmh, but while doing so I experienced over a period of two days time a total of four limb modes. The car went into limb mode at speeds between 210 and 270.

Today I went to my dealer asking for a read out of the error messages. The dealer needed the car for two hours to do this. I was like uh wait get me a computer and I will do the readout myself. The desk mechanic put the car on a bridge and looked underneath it and said nothing looks wrong...

I was like: and would you be able to "Get the computer, please". He walked back to his desk and started to write a report asking me to hand over the car for a two hour check with five different points they would need to walk through. I said "Leave it, I am going to a tuner".

Ended up at a local tuner, connected the computer and found the error messages! They said: Charging pressure control, plausibility pressure too high and Charging pressure control: Switch-off as consequence.

The charging pressure sensor got a value which is higher than the nominal value and so the car went into limb mode. I can easily reproduce it by doing those top speeds and keep pushing the car.

Any thoughts on this forum what this could be related to? Any input is welcome.

MR

First , please advise what mods your vehicle has that deviate it from stock, if any. Down pipe, tune , whatever.


Why did you have a tuner pull the codes instead of the dealer ? Isn't the car under warranty ? Or perhaps the answer to my query above is that the car isn't stock ..?

[MR.]

Originally Posted by M3 Adjuster

First , please advise what mods your vehicle has that deviate it from stock, if any. Down pipe, tune , whatever.

Why did you have a tuner pull the codes instead of the dealer ? Isn't the car under warranty ? Or perhaps the answer to my query above is that the car isn't stock ..?

Akrapovic downpipe + catalytic converter and full titanium exhaust and that are all the technical changes. Nothing else is fitted to the car that influences the drive train. There is no tune or anything.

As explained above the dealer needed my car for two hours somewhere in the near future and I do not have time for that. Costs me half a day to give it to them for 10 minutes work.

Local guy connects the analyzer and I have the details I want, so that I can investigate first myself before going back to a dealer who normally just removes them and says "We could not find anything, all looks well, if it comes back let us know."

I prefer to drop them a decent report of all my findings and share that with them next to all the others issues I have with the car, and then I can drop it at the dealer and say good luck fix it all under warranty please.

MR

[PackPride85]

Originally Posted by MR.

Akrapovic downpipe + catalytic converter and full titanium exhaust and that are all the technical changes. Nothing else is fitted to the car that influences the drive train. There is no tune or anything.

As explained above the dealer needed my car for two hours somewhere in the near future and I do not have time for that. Costs me half a day to give it to them for 10 minutes work.

Local guy connects the analyzer and I have the details I want, so that I can investigate first myself before going back to a dealer who normally just removes them and says "We could not find anything, all looks well, if it comes back let us know."

I prefer to drop them a decent report of all my findings and share that with them next to all the others issues I have with the car, and then I can drop it at the dealer and say good luck fix it all under warranty please.

MR

No dealer is going to just fix something based on 3rd party findings. They're going to need to do whatever diagnostic BMW says to do even if it takes 2 hours.

[David1]

Put the stock downpipe back on and test.

[PackPride85]

Originally Posted by David1

Put the stock downpipe back on and test.

Ah yeah forgot about that. Definitely take it off and try before going to the dealer. They'll point at that immediately if you leave it on.

[MR.]

Originally Posted by PackPride85

No dealer is going to just fix something based on 3rd party findings. They're going to need to do whatever diagnostic BMW says to do even if it takes 2 hours.

It is slightly different here in CZ. Dealers here often sent people to the guy I went to this afternoon when they do not want to deal with the problem anymore. Some cases they simply do not know it anymore, and this third party person dives in the problem and writes a report on which the dealer bases it next steps. Yeah that is not common, I was also amazed, but it tends to happen here.

So it depends, if in the end they are going to be the party fixing it. At that moment, I can then at least point them into the right direction, which helps in many ways lowering the cost and time they looked at the issue or will look at it, but for now I first need to find more information before even considering or starting the long diagnostic process.

Originally Posted by PackPride85

Ah yeah forgot about that. Definitely take it off and try before going to the dealer. They'll point at that immediately if you leave it on.

No time to test anymore with the winter around the corner, but it is definitely an option that is on my mind. It is also why I needed to collect the info from the on-board computer before having a dealer work 2 hours on it, charging me for it and immediately pointing at an aftermarket part. In the end, it could also be a faulty sensor or something else and dealers tend to take the easy route charging you for things without properly looking.

I also haven't installed my delete-r yet, so potentially that could also be the final solution to this. Although it is normally not required for this downpipe. Let's wait and see. I will keep you posted finding a solution that will help people here if they ever come across it. For now this is just the charme of working on your car.

Anyone else with a possible scenario, other than the downpipe?

MR

[Romo]

I`ve had it 2 times on high speed Autobahn driving, my car is stock.

Reported it tot my dealer and they did a complete software run over and installation.

Last saturday I did the fly low high speed maneuvering again and had no issues what so ever.

[MR.]

Originally Posted by Romo

I`ve had it 2 times on high speed Autobahn driving, my car is stock.

Reported it tot my dealer and they did a complete software run over and installation.

Last saturday I did the fly low high speed maneuvering again and had no issues what so ever.

What error message did you have?

MR

[zenmaster]

"Limp" mode.

[Artemis]

Originally Posted by MR.

Akrapovic downpipe + catalytic converter and full titanium exhaust and that are all the technical changes. Nothing else is fitted to the car that influences the drive train. There is no tune or anything.

Did your M2 ever go into limp mode during Autobahn stints before all Akra gear was installed ?

[MR.]

Originally Posted by Artemis

Did your M2 ever go into limp mode during Autobahn stints before all Akra gear was installed ?

Nope, but there is no guarantee that after 10K km with downpipe and exhaust fitted, it could be related. You cannot exclude it, but you also cannot say it is the case. The time between both Autobahn runs is more than 1.5 months, so there is no immediate correlation and we drove the M2 up to its ultimate max during those weeks. Maybe something broke down, who knows...

There is also no fixed answer to it yet until the right people look at it, we have found it and come up with right answer. At this moment I am just investigating all the options and asking here if anyone experienced the same. When I find it, I will report the result here so that we can learn from it.

And since Romo reported something similar you cannot exclude anything, so let's wait and see what comes in more. At this moment all the options are still open for me.

MR

[M3 Adjuster]

Originally Posted by MR.

It is slightly different here in CZ. Dealers here often sent people to the guy I went to this afternoon when they do not want to deal with the problem anymore. Some cases they simply do not know it anymore, and this third party person dives in the problem and writes a report on which the dealer bases it next steps. Yeah that is not common, I was also amazed, but it tends to happen here.

So it depends, if in the end they are going to be the party fixing it. At that moment, I can then at least point them into the right direction, which helps in many ways lowering the cost and time they looked at the issue or will look at it, but for now I first need to find more information before even considering or starting the long diagnostic process.

No time to test anymore with the winter around the corner, but it is definitely an option that is on my mind. It is also why I needed to collect the info from the on-board computer before having a dealer work 2 hours on it, charging me for it and immediately pointing at an aftermarket part. In the end, it could also be a faulty sensor or something else and dealers tend to take the easy route charging you for things without properly looking.

I also haven't installed my delete-r yet, so potentially that could also be the final solution to this. Although it is normally not required for this downpipe. Let's wait and see. I will keep you posted finding a solution that will help people here if they ever come across it. For now this is just the charme of working on your car.

Anyone else with a possible scenario, other than the downpipe?

MR

Another person on the forums here @photos_ by_ronnie

had a failure of an O2 sensor at some point after he installed a downpipe...... sounds like your issue may similar...

http://f87.bimmerpost.com/forums/sho....php?t=1312652

[Romo]

Originally Posted by MR.

What error message did you have?

MR

Limb mode mode indeed, not all power available and drive moderately.

The 1 st warning I did put the car on a parking lot as fast as I could, engine off and restarted, warning lights of.

Driving of the pedal to the metal, after 5 minutes of fast driving the 2nd waring, same as the first. I drove at moderate speed to my house.


Checked the dealer, they checked software; no problems reported, it was a software malfunctioning according to the dealer. They recommended a complete software re-installation, after this was done no further problems until now.

[MR.]

Originally Posted by Romo

Limb mode mode indeed, not all power available and drive moderately.

The 1 st warning I did put the car on a parking lot as fast as I could, engine off and restarted, warning lights of. Driving of the pedal to the metal, after 5 minutes of fast driving the 2nd waring, same as the first. I drove at moderate speed to my house.

Checked the dealer, they checked software; no problems reported, it was a software malfunctioning according to the dealer. They recommended a complete software re-installation, after this was done no further problems until now.

Interesting! There must have been a log in the on-board computer. The car does not go in limp mode out of nothing. Really interesting it did not record a message in the error log or the dealer just did not look properly.

MR

[MR.]

Originally Posted by M3 Adjuster

Another person on the forums here @photos_ by_ronnie

had a failure of an O2 sensor at some point after he installed a downpipe...... sounds like your issue may similar...

http://f87.bimmerpost.com/forums/sho....php?t=1312652

Thanks! Good read... It could be my pressure sensor... Time will tell

MR

[JDMAF]

so let me get this straight - you change the downpipe and exhaust and do not tune the car. Then the computer figures out that something aint right and throws it into limp mode. Forgive me but it seems to me what is more surprising is that the computer let the thing go as long as it did. I mean you say nothing was changed on the driveline - but a downpipe is a big deal - which is why it can make such a difference in performance. I come from the world of subarus and the simple rule for those engines is that if you change a downpipe you NEED a tune or expect all kinds of havoc. Now granted BMWs are very different from subbies, but jeez how can you change out the downpipe, not tune the thing and expect everything to be fine? - also to me it seems its way after the fact to claim that this would have happened if you had remained stock just because someone else had a similar experience on his stock motor. Hope everything works out - but you do pay to play. Mod the thing and you take your chances.


EDIT: - I was just surfing around about downpipes for the N55 and came across this blurb on the COBB website regarding their downpipe. - just so I'm not crazy about swapping in a downpipe on your $55k Mcar and not tuning it - clearly the recommendation is that you should tune the thing when you change the downpipe.

"It is a direct replacement. However, proper tuning is required to take advantage of the increased air flow and prevent any CELs. The best way to do this is with the Stage2 maps (made specifically for this downpipe) on the Accessport."

[MR.]

Originally Posted by JDMAF

so let me get this straight - you change the downpipe and exhaust and do not tune the car. Then the computer figures out that something aint right and throws it into limp mode. Forgive me but it seems to me what is more surprising is that the computer let the thing go as long as it did. I mean you say nothing was changed on the driveline - but a downpipe is a big deal - which is why it can make such a difference in performance. I come from the world of subarus and the simple rule for those engines is that if you change a downpipe you NEED a tune or expect all kinds of havoc. Now granted BMWs are very different from subbies, but jeez how can you change out the downpipe, not tune the thing and expect everything to be fine? - also to me it seems its way after the fact to claim that this would have happened if you had remained stock just because someone else had a similar experience on his stock motor. Hope everything works out - but you do pay to play. Mod the thing and you take your chances.


EDIT: - I was just surfing around about downpipes for the N55 and came across this blurb on the COBB website regarding their downpipe. - just so I'm not crazy about swapping in a downpipe on your $55k Mcar and not tuning it - clearly the recommendation is that you should tune the thing when you change the downpipe.

"It is a direct replacement. However, proper tuning is required to take advantage of the increased air flow and prevent any CELs. The best way to do this is with the Stage2 maps (made specifically for this downpipe) on the Accessport."

Completely agree with you, but Akrapovic stated differently to me. They said only the catless downpipe needed a tune and not the one I have.

Else I would have had the tune already. So let's wait and see what the outcome will be and we act accordingly.

I also have the Awron display which can act as a delete-r. That might also be the solution, although it is ony against CEL codes and not limp mode.

MR

[Artemis]

If recurrent problem, remove the Akra DPs, retrofit the original/stock DPs and see if the car still encounters a limp mode during or after a spirited stint on the Autobahn. Also keep an eye on the temp values shown by your AWRON gauge.

Cannot make sound statements about the Akrapovic exhaust for the M2. Akra has an excellent reputation, but they did not conceive the M2. The BMW M Performance exhaust consists of axle back + midpipe. Very likely BMW conceived and fine-tuned the infrastructure with the original/stock M2 DPs to perfectly comply/match with each other.

[MR.]

Originally Posted by Artemis

If recurrent problem, remove the Akra DPs, retrofit the original/stock DPs and see if the car still encounters a limp mode during or after a spirited stint on the Autobahn. Also keep an eye on the temp values shown by your AWRON gauge.

Cannot make sound statements about the Akrapovic exhaust for the M2. Akra has an excellent reputation, but they did not conceive the M2. The BMW M Performance exhaust consists of axle back + midpipe. Very likely BMW conceived and fine-tuned the infrastructure with the original/stock M2 DPs to perfectly comply/match with each other.

Yup that is a possibility, but there are also other options. Time will tell what the solution will be.

MR

[SliChillax]

Maybe it's due to having a downpipe without a tune? I don't know. As others have said, put back the stock downpipe and test it out. I highly suggest a remap/chip with the downpipes though.

[MR.]

Originally Posted by SliChillax

Maybe it's due to having a downpipe without a tune? I don't know. As others have said, put back the stock downpipe and test it out. I highly suggest a remap/chip with the downpipes though.

At this moment I simply do not know. I need to wait for more information. When I have it, I will share it here.

MR