Pulled Codes After X5 Started Misfiring - Confusion Ensues...

[Bayerische E53]

Hi All,

My X5 started misfiring BADLY a few weeks ago. I used a friend's GT1 to pull the codes and the only thing we found was that Cylinders 1 and 5 were misfiring. We thought it might be the spark plugs so we changed them. This only helped the issue but did not completely remedy it. The car kept misfiring slightly. About a week and a half ago, the misfiring came back pretty badly. So, by power of deduction, I figured bad ignition coils were causing the problem. I bought 6 used coils from a friend who had a set sitting around that he pulled off his racecar. I figured I'd replace the coils in Cylinders 1 and 5 and keep the other 4 as spares. After all, I've got 3 M54 cars. Fair enough; so I thought.

Here's where the problem begins. I decided I'd wait to change the coils until I got a Peake Tool to make certain of the codes. The Peake Tool just came in. I pulled the codes and I'm stumped.

The Peake Tool did not report any codes showing that the coils were bad. According to the Peake Tool, not a single coil is bad. Huh? Further, the Peake Tool says that, among other woes, 5 of my cylinders are misfiring now as opposed to only 2 just a few weeks ago. Huuuhhhh???

Maybe someone can help me interpret the codes the Peak returned. Those codes are:

CA: 02 Sensor Control Limit, Cyl. #1-3
CB: 02 Sensor Control Limit, Cyl, #4-6
CC: Idle Control System, Idle Speed Not Plausible
E3: 02 Sensor Adaptation Limit, Cyl. #1-3
E4: 02 Sensor Adaptation Limit, Cyl. #4-6
EE: Misfire, Cyl. #1
EF: Misfire, Cyl. #2
F0: Misfire, Cyl, #3
F1: Misfire, Cyl, #4
F2: Misfire, Cyl, #5

Apparently, Cylinder 6 isn't misfiring. How is this possible when the other 5 are? How could the GT1 not have picked this stuff up? Two preliminary questions: 1) Did I not use the GT1 properly or 2) Is my Peake Tool wrong?

Well, I guess I should ask one more question: Am I doing something incredibly stupid (i.e. Am I an imbecile?)?

I could have sworn that it was bad coils causing the misfiring. If my Peake Tool is correct, what does all this mean - bad 02 Sensors? Boy, that would be a bear.

And what about the idle speed not being plausible? The Peake Tool did not report an ICV/DISA code so I imagine those aren't causing the idle speed code. I would imagine that the misfiring, which caused a low, rough idle, has triggered this code - but, because I have apparently been wrong about everything else, I'm cautious about jumping to such a simple conclusion...

I appreciate any help.

Thanks, guys and gals.

[SlickGT1]

Curious what would happen if you started with an unplugged maf? That is a lot of codes.

[Bayerische E53]

Did a little more digging around online and the only thing I have found is speculation. Some people say a similar problem was fixed after changing the DISA, others have reported fixing the problem after replacing the CCV system, others have reported fixing the problem after replacing the pre-cat O2 sensor, while others have reported fixing the problem after simply cleaning the MAF. On the other hand, there are others who have tried this entire combination only to have the problem persist.

Roh, oh - not feeling good about this one...

[tynashracing]

Originally Posted by SlickGT1

Curious what would happen if you started with an unplugged maf? That is a lot of codes.

Ha, actually did this last week...by accident of course. Nothing happened, just hard to start and once started, obvious something was wrong. It didn't throw any lights...maybe I should check for codes? But, it's running really well.

[SlickGT1]

Lol. Yes run codes. Getting the codes read won't make your car blow up. You need to check what's up.

[tynashracing]

Originally Posted by SlickGT1

Lol. Yes run codes. Getting the codes read won't make your car blow up. You need to check what's up.

OK, I'll check it out.
I'm curious though, when codes are stored but no dummy lights are lit on the cluster, can or does the ecu change the behavior of the operating system? Or, is it more of a tattle tale system to show what's been done to the vehicle in the event something does blow up so warranty work can be denied?

[TwinsPoppa]

With the GT1 you should have a test plan available. Did you follow the test plan?

I would clear any codes you can and re-run Diags in DIS. Then see what faults appear. Then follow the test plan for said faults.

[Giznaz]

Originally Posted by tynashracing

can or does the ecu change the behavior of the operating system? Or, is it more of a tattle tale system to show what's been done to the vehicle in the event something does blow up so warranty work can be denied?

Yes the operation changes. Why? i don't know.

When my X5 throws mis-fire codes, and I have the Peake connected while running, clearing the codes makes it run much better.

[TwinsPoppa]

With the GT1, some faults cannot be cleared (un-selectable & undeletable) until the required repair is done.

Also, some faults have to be cleared by:

1) Clear faults.

2) Engine on. Engine off.

3) Clear faults.

Then there are faults that will not clear until after an actual short drive.

[sockethead]

a vacuum leak is another possibility.. I know that the e46 has a problem with the intake boot cracking, don't know if that's the case with that engine in the X5 but it's worth mentioning