bmw - full engine power not available light

mcshape

Guys the wife got this yellow lamp on her 06 318i when starting it this morning, any idea what it is?

mikewest

Which yellow lamp?

mcshape

The manual describes it as "full engine power not available", I was speaking to her on the phone and she said it looks like a pic of a valve, she compared it to the manual and that's where I got the description from

falabo

If the light is a graphic that represents the silhouette of an engine, then it is the EOBD (European On-Board Diagnostics) light which primarily serves to warn the driver that their car is not performing properly from an emissions perspective.

http://en.wikipedia.org/wiki/On-board_diagnostics

This can show up for a number of reasons. The Engine Management Computer may have detected a problem with the engine or with something in the ignition sequence. Sometimes this can be a sign of a very serious fault, or sometimes it can simply mean the ECU has messed up and just 'thinks' there is an error. It can also come on if there is a problem with the Lambda Sensor for the Catalytic Converter in the exhaust system. Either way the computer stores the fault code in the memory which can be retrieved by a garage come servicing, even if the light extinguishes before that.

I recently had this show up on my Alfa 156 when I had the battery replaced and I turned to an Alfa specialist boards to ask the posters there if they might know why. One guy suggested that sometimes they appear for little or no reason and that they can go out as easily. I took this with a pinch of salt but after 3 months of it being on it suddenly disappeared the other evening, mere days after this was suggested to me.

The only thing I could think of that I had done differently that day to any other was, I had sat in the car for a few mins earlier that day with the ignition key turned to the MAR position so I could run the stereo. I'm wondering if maybe jumping in the car every morning and evening, starting it immediately without ever leaving the key at the MAR setting for a few seconds was not the cause of the battery change resulting in an error.

If it is a serious fault the EOBD light should flash. In that case I wouldn't drive the car at all and I'd have a garage look at it pronto. If the light stays constant though it shouldn't be anything serious and may just be some error identified in the ignition sequence or with emissions. I have also read somewhere that this light can also come on if there is a problem with the 'knock sensor'. Unfortunately, this is something I know nothing about.

I am not certain of this but it is also possible that when this light appears it is because the MAF (Mass Airflow) Sensor has failed or is in the process of failing. If that were to happen the engine would not perform properly and the emissions would also be bad. The symptoms for a failing or failed Lambda Sensor and MAF Sensor are I am told very similar.

I am told that if the EOBD light is on, it is an automatic fail for the NCT as the ignition warning lights are the first thing that a tester checks for when they start the car. If the Engine Management Computer is telling the tester that there is a major fault with the engine, there is no point going any further.

Hope this is some help.

mikewest

Taking a wild guess here and assuming you are talking about the EML light, this usually means a trip to a garage for a diagnostic.

Edit: too late, but it could be anything from a faulty coil pack to an engine in bits all over the road.

mcshape

Its a bit generic all right, well we have only had it a month so I've told her to bring it straight down to the garage today

mcshape

And actually, makes sence now, i was driving it at the weekend and found it very sluggish and DRINKING petrol for sport

MarkN

I got the same light in my last BMW, it's more than likely a fuel injector.

Make sure they do it under goodwill if it is, it's an extemely common fault in the E90s.

mcshape

Yep its in the garage tommorow, ill mention that to them! Thanks all

mcshape

went to the garage today, of course the light was off when they got it, They are saying that the logs showed no fault so have sent it back to us as is, They did however say if it happens again they will send it to bmw for a full diagnostic...