2001 525i Lots of codes but driving perfectly - BMW Forum

adrian@candyjar · 07-22-2009, 05:19 AM

First time post!

Was hoping some of you guys with lots of experience in diagnosing Engine light problems could have a look at this and give me some idea where to start.

01 525i driving perfectly--no stuttering, starts every time--good performance when accelerating--cant feel anything wrong really but engine light on. 60,000 miles on clock.

Codes are as follows:

P0123: Throttle/Pedal Position Sensor/Switch A Circuit High Input

P0228: Throttle/Pedal Position Sensor/Switch C
Circuit High Input

P0227: Throttle/Pedal Position Sensor/Switch C Circuit Low Input

P0202: injector circuit malfunction: Cylinder 2

P0203: injector circuit malfunction: Cylinder 3

P0238: Turbocharger Boost Sensor A circuit high

P0239: Turbocharger Boost Sensor B circuit malfunction

P0240: Turbocharger Boost Sensor B circuit range/performance

If this was all wrong surely it would feel like a tractor to drive?

Any ideas where to start -- GREATLY appreciated.

Thanks Guys

rashid · 07-22-2009, 02:37 PM

How you've got the codes? on dash or you use scanner software?

adrian@candyjar · 07-22-2009, 04:43 PM

Thanks for the reply Rashid

Got codes from a local mechanic who has the scanner but doesnt service BMW so cant fix it.

rashid · 07-22-2009, 08:55 PM

What modification you have on it?

You may need to verify the error codes again before fixing.

BTW, have you tried to reset or disconnect the battery for few minutes?

adrian@candyjar · 07-23-2009, 12:51 PM

no mods at all. Completely factory spec.

Havent tried disconnecting the battery. But I took it out today and it wasn't running 100%. Shuddering and rattling more than usual but still driveable. Took it out again and it was fine.

BimmerE39 · 07-23-2009, 12:54 PM

Hmmm, this is the one area I'm still trying to learn. Understanding codes is like trying to decipher a foreign language without a translator.

rashid · 07-23-2009, 03:35 PM

I also have no experience on error codes & scanner S/W. but I failed to understand the meaning of Turbocharged error messages in 525i. I would advise you to make sure that the scanner used in Bimmer specific & not generic one. I think this is important for correct diagnostic.

Meanwhile, a software reset or battery disconnection can resolve such issues sometimes.

adrian@candyjar · 08-24-2009, 08:42 AM

Rashid--You were 100% right--Generic scanner producing irrelevant codes.

Ended up taking this to the local dealership.
They opened the bonnet and without scanning listened to it and said your breather cap or pipe is faulty.

They took it in and replaced the pipe and cap.--Reset the computer-no codes --driving like new.

Obviously they knew what to look for and this is perhaps something they have seen before....just posting for fututre reference for others.

witeshark · 08-24-2009, 08:50 AM

Nice of you to share that, glad it's sorted!