first off check the breather pipe at rear of rocker cover when these split it will misfire the throttle and map senor will try and level the closed system being open and cause codes related to throttle,, that said its also possible the throttle body could be at fault, check the est cheap bits first. also check the oil filler cap seal is good, best way to check this system is a smoke machine, but if not got one removing and checking cheapest way, also can use easy start can to spray carefully at the rear breather pipe with engine on idle if revs increase then thats your issue, next on the list need a diagnostics you can run live data so read the injectors see what its all doing, autocom cdp plus on ebay good for this,Hi, hoping someone can help. I have an 08 Cooper S.
I have recently had the following happen whilst driving on motorway at steady speed.
Cruise Control Failure light came on on dash followed instantly by loss of throttle response & check engine light.
Got it onto hard shoulder & got recovered.
Codes showing are P2103, P1637 & P1638 which all seem to be related to throttle valve.
Engine has been apart with new rings, timing chain, deoke etc etc & has no carbon build up at all.
If I switch it off for 10 mins say then I can drive it fine for 30 secs, maybe a minute or 2 but then throttle does the same thing & just doesn't rev up, only stutters to approx 2000rpm.
Engine hunts wildy on tickover too.
It did the same thing a few months ago but without showing the codes only the crusie control failure light(cruise control wasn't on on either occassion) & check engine light.
Switched it off for 10/15 mins & then it was fine & has been until the other day when it did it again about 100 miles into a trip but now with the 3 fault codes.
Basically what I wanted advice on was do I change the throttle body & go from there or is there something else more likely to be causing the fault ?
here's hoping you guys can help me, thanks.
worth sticking some injection clean through the system i use seafoam it will very slightly white whispy smoke on idle for a few days while its in there but if its got dirt anywhere it will clear it, without live data read whats misfiring and when it will just become a throw apart at it project ans thats expensive,