engine management light coming on

Wonder if anyone can advise. I haven't used my car for the last week or so. When starting to drive it this morning it was as though the breaks were still on until the car started to move. The cold weather really seems to affect the break pads on the discs. However, this is always quickly resolved. Upon 10 minutes of driving with no real problems other than the idle speed sort of slightly fluctuating and the acceleration slightly behind expectations when pressing the accelerator, the engine management light has come on. I thought the car probably just needed to warm up after sitting still for the week. I know this doesn't give a lot to go on but is there enough here to possibly pinpoint some possibilities. I will try the car again later to see if the light remains on, any advise would be appreciated, ps This has never happened before MY98 C2 996 Thanks, David

Not a lot to go on without a fault code but at this time of year with temperatures as they are, condensation finding its way into a cracked coil pack could be one possibility...

I have just been onto ebay to see if i can purchase a diagnostic reader. As per usual all cars listed except porsche. Could someone lead me to the correct diagnostic reader please as i would be interested in having one permanently and discovering why the engine light has come on. Once purchased you can guess my next question.....what does the code mean etc. Many thanks for your reply uk_sub, i'll bear this in mind. I see lots of comments on MAF. I suppose i shouldnt rule this out yet!! I suppose the diagnostic reader will put me in a better position.

Does anyone know if this is compatible....just found it on ebay new. States it does porsche....does anyone have one to confirm. Seems a snip at £25 ELM 327 CAR DIAGNOSTIC CODE READER SCANNER LATEST V1.3A

It's a bit of a grey area. MY98 uses the Motronic version 5.2.2 engine ECU. US cars with 5.2.2 are completely OBD2 compliant, but RoW cars are not. Some code readers will read fault codes and pending fault codes, but others won't. The US cars will switch on the Check Engine Light on almost all fault codes, whereas RoW cars won't. As I understand it, in this case the fault code is stored in a separate fault register, but won't illuminate the CEL. When I first got my MY98 C2 I bought a hand scanner. This would read engine sensor values, but not the 'hidden' fault codes. I also bought a mOByDic scanner for my laptop, which did exactly the same thing. However, I know someone on this forum who has a cheap hand-held code reader which reads fault codes on his early Boxster and 996, so clearly some units are compatible, and some aren't. Sorry that I can't give a positive answer about this particular scanner. Later 996s with Motronic version 7.2 and 7.8 (eGas cars) are fully EOBD compliant, and so that scanner would be fine. I think that you should ask the seller - they may have some experience of someone using one with an early 986 or 996. If it is compatible, those scanners usually come with some very basic software. If you want something better, try and obtain a copy of Digimoto Lite, which is a very comprehensive freeware program. The best DIY diagnostic tool for the Porsche is the Durametric tester, but it is much more expensive. However, it will do a lot more than a code reader/scanner as it will work on the other systems in the car, such as airbag, alarm, aircon, instrument cluster, abs, etc, etc.

Thanks Richard, i will phone the company.

Strange thing.....before i could identify which diagnostic reader to buy, the engine light has now switched off. I suppose this is alright and can therefore wait for any further action that may or may not be required can wait until i have put the car in for its service. Maybe having it stood still for the week, which has never been the case before, just needed some driving. Yippee[ ][ ]

If a fault is rectified (or goes away) the fault memory will clear itself after a number of driving cycles. Whatever caused it is obviously OK for the moment, so it is probably just one of life's little mysteries. Hopefully it won't come back.