Limp mode and brakes?

[fusion01]

So I'm doing some short WOT's (x5 at most), then hit the highway and cruising along at decent speeds - nothing that is pushing the car much - then cruise into a nice downhill curve at speed, applying some brakes (as you must) and after coming out of all of this (I'd say a spirited run all-in-all but certainly less than many of my weekend jaunts) my car goes into limp mode, complete loss of power (pleased the Scirroco didn't take me up on my offer as that's exactly when it happened!). I limp home for all of the return journey home.

I'm thinking HPFP, injectors, coil packs etc.

Get the car into my BMW dealer 2 days later (not driven since that night and all is now perfect, no loss of power) and it gets ye 'ol diagnostic treatment.

So this is the outcome: 'Driving Performance Reduction: The engine output was temporarily reduced (measure for preventing possible overheating of brakes).'

Codes were cleared and some sort of measure put into place to 'adapt to my driving conditions' (as stated by the service dept). But nothing else.

Does this hold weight? I find it bizarre that it was a short run before limp, nothing too hectic was thrown at the car and it should nannie me then so soon into submission. I was told it has to do with the DSC system but of course I'd rather not turn this off to circumvent this, due to my own personal safety.

I do hope I'm not faced with this again in the short-term, my previously-owned Golf 5 GTI took beatings without fuss. As I've said, I taken far more spirited runs over the last 2-3 months of ownership without limping home in my 135i.

Has anyone had any experience of this sort of thing and could the diagnosis be incorrect with bigger things to come?

[RPM90]

Originally Posted by fusion01

So I'm doing some short WOT's (x5 at most), then hit the highway and cruising along at decent speeds - nothing that is pushing the car much - then cruise into a nice downhill curve at speed, applying some brakes (as you must) and after coming out of all of this (I'd say a spirited run all-in-all but certainly less than many of my weekend jaunts) my car goes into limp mode, complete loss of power (pleased the Scirroco didn't take me up on my offer as that's exactly when it happened!). I limp home for all of the return journey home.

I'm thinking HPFP, injectors, coil packs etc.

Get the car into my BMW dealer 2 days later (not driven since that night and all is now perfect, no loss of power) and it gets ye 'ol diagnostic treatment.

So this is the outcome: 'Driving Performance Reduction: The engine output was temporarily reduced (measure for preventing possible overheating of brakes).'

Codes were cleared and some sort of measure put into place to 'adapt to my driving conditions' (as stated by the service dept). But nothing else.

Does this hold weight? I find it bizarre that it was a short run before limp, nothing too hectic was thrown at the car and it should nannie me then so soon into submission. I was told it has to do with the DSC system but of course I'd rather not turn this off to circumvent this, due to my own personal safety.

I do hope I'm not faced with this again in the short-term, my previously-owned Golf 5 GTI took beatings without fuss. As I've said, I taken far more spirited runs over the last 2-3 months of ownership without limping home in my 135i.

Has anyone had any experience of this sort of thing and could the diagnosis be incorrect with bigger things to come?

Probably just one of those ECU hiccups that seem to happen randomly in modern cars like this one where everything is connected and controlled by the ECU. I wouldn't worry about it unless it happens again.
On this forum every once in a while we get a thread about some 1 series doing some random limp mode. Most seem to get cleared by simply shutting off the car and starting it back up. Very odd.

Did you try shutting the car off and starting it back up?
If it happens again try it. At best you'll be back to 100% performance.
At worst you're back at the dealer and asking for a REAL fix.

That "reducing power to prevent over heated brakes" sounds odd though. I don't recall knowing that the ECU had a sensor for brake heat.

Good speed and have fun.

[fusion01]

Originally Posted by RPM90

Probably just one of those ECU hiccups that seem to happen randomly in modern cars like this one where everything is connected and controlled by the ECU. I wouldn't worry about it unless it happens again.
On this forum every once in a while we get a thread about some 1 series doing some random limp mode. Most seem to get cleared by simply shutting off the car and starting it back up. Very odd.

Did you try shutting the car off and starting it back up?
If it happens again try it. At best you'll be back to 100% performance.
At worst you're back at the dealer and asking for a REAL fix.

That "reducing power to prevent over heated brakes" sounds odd though. I don't recall knowing that the ECU had a sensor for brake heat.

Good speed and have fun.

Thanks for the feedback. Yes, next time I'll switch it off and then on again - reboot! - and I'm sure all will be fine. However that is a bit of a contradiction to 'I wouldn't worry unless it happens again'

Honestly I won't be worried, I think this car is just prone to quirks (after the dealer had serviced it, my radio switched on automatically twice and my power window wouldn't automatically return to close, would stop when I released the switch -fixed itself after a while).

If it carries on more than a few times I'll have it seen to. I think the brakes issue was just rubbish.