My ASC light has been sticking on when i boot the car accasionally but now the EML light stuck on with P0108 map sensor high voltage! car still ran ok no limp and ive cleared the code ok, but ASC still sticks on . someone said im over boosting im running a 15% pulley and cia and one box exhaust mod ! Its happened ever since i have owned the car 1month already modded!

cheers for your help in this matter as its very annoying!#

I have access to live readings and fault code reader

 

If you are located in a cold climate, it could be the air density, combined with high-revving which might be causing your overboost code. Your car is new to you? do you have an oversized crank pulley?

 

hi i live in UK and its 0 celcius at the mo lol, the car is new to me and it only happens when i really give it some but i wanna fix the prob its so annoying, im gunna clean my MAP sensor see if this helps then ill read my boost levels. No my pulley looks standard its weighted anyhow

cheers for help

 

I don't think cleaning, or even replacing it will do the trick (at least it's not guaranteed to--I've tried). You might try swapping the two map sensors. I've never actually done it, and I believe that they have different part numbers, but just give it a try. The one on the side of the cylinder head (TMAP) also is used as a temp sensor, so it may not fit as the MAP sensor. I'm at home now so I can't check for you. Anyway, your car is breaching a voltage threshold which trips the code, and maybe the other sensor will be just within spec. I think that the threshold is the voltage that corresponds with 18 pounds of boost, which you certainly are not making, even in the cold weather, so theoretically, you sholdn't be getting that code...

 

if you swap the map and tmap sensors the car will run like *****. They have different measuring ranges in addition to one having the intake air temp. sensor integrated in.

 

get a boost gauge and see how much boost you are making. If you are getting over 18 psi i would suspect an exhaust restriction

 

ill have a look at the boost on the intake map on live readings see what it max' out at on the motorway i had all this crap with my VAG 1.8t 20v had to solder a diode in the loom in the end to stop limp! I suspect this car has been heavly tuned and had all the stuff removed apart from the pulley , maybe if i fit an uprated intercooler de-cat and manifold it may run alot better it does feel restricted at certain revs , and i went to fit iridium plugs and it already had em in LOL also it has a tpiece blocked off where it lookes like a boost gauge was once fitted on the o/s of the manifold under the cooler .
If it de-cat it can i trick the ecu by fitting the second lambda sensor in a sleeve ??
done alot of tuning on VAG cars but never dealt with bmw systems

cheers again for your time

 

boosting at 1.2 bar max which is 17psi cleaned both sensors and you were right it wouldnt run if i swapped em over tried it!!! Runs better now ive cleaned em and i have not managed to get the lights on again even with abuse

 

Hey Chris, FYI the 2 sensors have different PNs & they are both different. The upstream is a Cooper - non "S" part & the T-MAP is an "S" part.
If you go to a parts store there is only 1 sensor listed for the "S", it's the T-MAP - it will not work as an upstream MAF. The Cooper part is 0872648 up & 0872679 T-MAP....... just in case you need to replace either

 

cheers pal!!

 

Chris, How did you clean the sensors?