4.8 Misfire Detected Checksum Failure

[Dsquared]

Hey guys - I'm new here but stumbled upon your great site looking for some help. Lots of great stuff here..Thanks! However, having some trouble with a 04 4.8is i bought recently at auction. I don't know much about it's history, but looks like it was taken care of. 115K miles on it.
It keeps throwing a "Misfire Detected Checksum Failure" code. I'm using the Peak OBDII tool to detect this. I think this is the equivalent to "Random Misfire". but i'm not exactly sure. Occassionally, I'll get a cylinder misfire as well, but that's inconsistent.

It starts right up and idles what i would consider rough for a BMW. I have owned several, none idle like this thing..but then again..none of them rumbled like a V8 Muscle Car either. Can wait to actually drive it.

Things I have tried already;

Replaced the plugs, coils and CCV's. I also have run fuel treatment to try to clean the injectors..not sure they are dirty, but figured it couldn't hurt.

Plugs had normal looking wear. All of the old coils tested out between 0.7 -0.9 ohms. New ones tested the same. Not sure what normal range is, but they were all consistent.

CCV's were obviously damaged (failed).

The vehicle spent it's life down south in Texas and Florida before I brought it up here to Northern NY. The guy i bought it from said there was no "SES" light on when it left his place. However, minutes after I started it up the day it arrived (late November ~30F) the light came on.

Before I start throwing more time and money at it, I thought I'd see if any of you have come across this with similar circumstances or have any ideas where to look next.


i appreciate any help or feedback.

[upallnight]

What is the actual code that is being thrown up? Could be a vacuum leak.

[Dsquared]

It's throwing code 274E - "Misfire Detection, Checksum Failure" it has also thrown codes 2747 and 2742 which identify specific cylinders..but these are not consistent after i reset..but the 274E always comes back.

I thought about vacuum leaks..anything obvious to check that you are aware of? Any tests/tricks you'd suggest to test? I have seen the propane, carb cleaner, etc tests, but was a little hesitant to start spraying that stuff around a running engine. Thanks for the reply.

[upallnight]

People normally have a smoke test performed to find a vacuum leak.

[X5monsterBMW]

Hi there I am keen to know the answer to this!
3 months ago bought an X5 4.8is with full BMW service history.
It is a Dec 2004 vehicle & has done 79K miles only
It is lovely...... immaculate...... however......

Started it last week from cold and it sounded like it was not running on all 8... in fact more like 4 !
I stopped the engine - when I re-started it ran fine but left me with the dreaded warning light!

I changed the spark plugs as I thought that this is the easiest thing to start with - were probably due anyway.

I had the diagnostic run on the car and had the fault codes cleared.
This is what it said:

274E Misfire Detection, Checksum Failure
2748 Misfire Detection Cyl. 7
2743 Misfire Detection Cyl. 5
2742 Misfire Detection Cyl. 1
2744 Misfire Detection Cyl. 4

I realise that changing the plugs would not be the answer or indeed the coils as this happened all at once.

It has done it once more since on cold start but this time no fault light to clear - although it did flash whilst running for the 1st 15 seconds. Again switched off then next start was fine?

I have read some horror stories on the net about this and another post read..

On my 2004 X5 (60,000 miles) I am getting a rough idle and "service engine" light flashing when doing a cold start in very cold weather. I took it to two BMW certified mechanics
We were told by several repair places that we needed to have our "valvetronic intermediate levers" replaced as documented in service bulletin SI B 11 02 05. I read the bulletin and it is a big job and we were given rough estimates for over $3,000.

This has scared the pants off me and could cause me to regret the purchase...

Did you have any joy finding the answer??

Best
M

[TwinTurboGTR]

There have been a lot of possibilities to the rough idle due to cold. Some say intermediate levers, but some have also spent the coin only for it to come back. It's hit and miss. Sometimes it happens, sometimes it doesn't. Mine did it the first year I had it. When it god cold, mine would stumble and the CEL would flash... If I shut it off and restart, all is good. If I revved the motor just above 1000 rpm, the light would stop flashing and the motor sounded fine. So I put the X in the garage and just started ripping the motor down to the valve covers. Surprisingly, everything was ok. CCV was good, nothing leaking. Start spraying the motor down with carb cleaner. Nothing. Start bending hoses and spraying cleaner, nothing. Had the system smoked, nothing. So I just went back to basic principles. I started with fuel... everything was normal... but did notice the o rings were dry. So I ordered new o rings and put them in. This was back in January... Since then I haven't had the problem come back. So I am assuming it must have been a very very small vacuum leak in all the injectors causing a pretty big leak.

Also, since these things are very sensitive to voltage. Check the power output for a week. Before you start and then after you start. See if there are any huge fluctuations.

[X5monsterBMW]

Hey - this is such a helpful forum... thanks to TwinTurboGTR for that reply - that was fast - I only joined the forum last eve and got your reply almost instantly after posting the above!

I am not a mechanic but have a fair understanding.

The 'o' ring thing makes much more sense to me and I guess the cold obviously effects these?

On a relatively low mileage engine which has always had oil changed at correct intervals it would be pretty disappointing to have to replace worn out intermediate levers?

The fact that you say that yours did it from new has given me some hope anyway!

Big thanks
M

[TwinTurboGTR]

Yeah, it is disapointing but while these motors require specific care, there are still oddities that go wrong with them. Before BMW most of the cars I owned required fluid changes, the occasional cv boot, and some light bulbs. After BMW, I am a pro at tearing down an M62 motor, can do CV boots blindfolded, a wiz at taking the door card off and replace a window regulator within 15 mins, and becoming astute to clunking, banging, and hissing noises. But.... It drives like no other car I have ever owned, including my Audi.

I mean I have seen examples where these levers have gone out in as little as 20k miles, but covered under warranty. Some have replaced them twice throughout their ownership. Being a BMW owner also means ponying up some coin to get it running just right. I've had the dumbest stuff fail on both of my X5's that I haven't seen on other cars. But then again... I've never been prouder than owning my BMW.

[Clockwork]

TTGTR, thanks for sharing that about the o-rings.
my mech told me after reading it with his software adn showing me the results on the live scree, it looks like my valvetronic system is out of range and he thinks it could be the levers being worn.
so yeah I'm ready for a big bill on that, but maybe I'll attach the o-rings first,,, but really am not sure if that will solve anything since I seen the GT1 (or what ever blue tablet he uses to read codes/errors).

PS: I assume you mean the fuel injector's o-rings?

[Clockwork]

Originally Posted by X5monsterBMW

On my 2004 X5 (60,000 miles) I am getting a rough idle and "service engine" light flashing when doing a cold start in very cold weather. I took it to two BMW certified mechanics
We were told by several repair places that we needed to have our "valvetronic intermediate levers" replaced as documented in service bulletin SI B 11 02 05. I read the bulletin and it is a big job and we were given rough estimates for over $3,000.

this is exactly what I'm seeing in my X5 now and how much I was told it would cost
sucks but thats the price you pay for playing with a nice performance toy.