E85 code deciphering

[Dr. Zed]

I've just ran a scan on my car with Carly and overall I really like it but sometimes it just throws back absolute nonsense.

I've swapped coils 4 (bad) with 1(good) as it was just saying number 4 was bad but now the new code makes no sense to me. The first screenshot there says cylinder 9!?

Anyone help with these?

 

[Dr. Zed]

Anyone at all? It's driving me nuts!

 

[enuff_zed]

Really sorry. I can never work out what Carly is on about. Seems unnecessarily obscure.

 

[bigwinn]

I usually put straight into Google:

BMW z4 fault code 27C3

Then have a sift through the hits that come up

 

[Mike6]

Get yourself the Creator 410 plus code reader. Cheap as chips and very good at reading and resetting codes.

 

[Dr. Zed]

Yeah, Carly has had a bit of a funny moment here and it's driving me up the wall!

 

[Dr. Zed]

I usually put straight into Google:

BMW z4 fault code 27C3

Then have a sift through the hits that come up

Did this but because one of them relates to a waste gate issue, it's giving me more confusing information!

 

[Dr. Zed]

Get yourself the Creator 410 plus code reader. Cheap as chips and very good at reading and resetting codes.

Will this do other cars as well or just bmw?

 

[BumpyZ4]

It does BMW/Mini

 

[Dr. Zed]

It does BMW/Mini

I'll check it out. Thanks!

 

[bigwinn]

Strange

When I put them in Google and do a bit of searching I get a misfire on cylinder 4 and the next two are related to the misfire- the o2 sensors detecting an over fuel?

 

[Dr. Zed]

Strange

When I put them in Google and do a bit of searching I get a misfire on cylinder 4 and the next two are related to the misfire- the o2 sensors detecting an over fuel?

I swapped the coil pack from cylinder 4 to 1 but then I ran the code reader again and it gave me that nonsense so not sure what's going on.

O2 sensors is something I'll check (when I find out where they are!). In the mean time I've ordered a new boot that comes from the air filter as that has a split in it. Quite a big one I may add so starting there as its very obvious that may cause a running rich error.

 

[Dr. Zed]

Strange

When I put them in Google and do a bit of searching I get a misfire on cylinder 4 and the next two are related to the misfire- the o2 sensors detecting an over fuel?

So I've had more time to look into this (realise it's been a while, got hammered at work with overtime). I've replaced an air line that I thought might cause the issue as it was badly cracked. It hasn't but was nice to fix that regardless.

The codes do mention lambdo sensors. I refuse to believe it's a misfire though as it's not running rough at all. Starts up perfectly and then idles as it should. Even under load it's fine.

So next course is the sensors. But I have zero experience with these. Where are they, and how do I replace them (ie is it hard or is it a DIY job).

 

[x-driver]

There are 4 O2 (lambda) sensors on M54 engine, 2 before cats and 2 behind. The front pair is more important as it measures pure exhaust gases and determines whether the combustion is good or not. The other 2 sensors are more like extra control of the first 2.
These sensors sometimes just get dirty and give wrong measurements and therefore fault codes. The ECU will adjust combustion parameters based on O2 sensors readings so it will ajdust those wrong if it's receiving wrong data from O2 sensors.
It is however recommended to replace them in any case of troubles.

It's also recommended to use original engine sensors as most others won't work correctly. I have good experience with Bosch however, works fine on my e39 for quite some years now.

After replacing the O2 sensors you must reset engine adaptations or you will face heavy increased fuel consumption.

The front O2 sensors are accesible from top, they sit on top of each exhaust manifold, you can do it yourself but you'll need some special tools to unscrew them. Just google O2 sensor tool.

 

[Dr. Zed]

There are 4 O2 (lambda) sensors on M54 engine, 2 before cats and 2 behind. The front pair is more important as it measures pure exhaust gases and determines whether the combustion is good or not. The other 2 sensors are more like extra control of the first 2.
These sensors sometimes just get dirty and give wrong measurements and therefore fault codes. The ECU will adjust combustion parameters based on O2 sensors readings so it will ajdust those wrong if it's receiving wrong data from O2 sensors.
It is however recommended to replace them in any case of troubles.

It's also recommended to use original engine sensors as most others won't work correctly. I have good experience with Bosch however, works fine on my e39 for quite some years now.

After replacing the O2 sensors you must reset engine adaptations or you will face heavy increased fuel consumption.

The front O2 sensors are accesible from top, they sit on top of each exhaust manifold, you can do it yourself but you'll need some special tools to unscrew them. Just google O2 sensor tool.

Cheers mate. Appreciate that.
What do you mean by engine adaptations?

I would have thought a sign of this fault would be rough idle etc. This is why this check engine light is confusing me so much because I have no other symptoms. No tough idle, no issue on start up, no lumpy running. No loss of power or limp mode.

 

[x-driver]

Apparently the engine adapts to every condition and components and their functioning. It would probably adapt to new O2 sensors with time, but very long time so you have to reset it manually to teach in again correctly. It has to be done via tester.

I don't think O2 sensors would cause rough idle or something like this. Rough idle would more likely be caused by coil plugs, MAF sensor, crankshaft sensor and camshaft sensors. Or some more serious issues.

 

[Mike6]

Didn't think you had to reset anything after replacing the sensors. I didn't and haven't noticed any difference.

 

[x-driver]

Didn't think you had to reset anything after replacing the sensors. I didn't and haven't noticed any difference.

Are you talking about O2 sensors or all sensors in general?

Of course you don't have to reset engine adaptations for all sensors, but for O2 sensors you have to.

 

[Dr. Zed]

Apparently the engine adapts to every condition and components and their functioning. It would probably adapt to new O2 sensors with time, but very long time so you have to reset it manually to teach in again correctly. It has to be done via tester.

I don't think O2 sensors would cause rough idle or something like this. Rough idle would more likely be caused by coil plugs, MAF sensor, crankshaft sensor and camshaft sensors. Or some more serious issues.

Thanks for the info!

Would O2 sensor issues cause misfire errors though?

 

[x-driver]

I don't think so. I'd replace the coil plug on the faulty cylinder first.