help ?????

[cauf41]

hi all
my x5 2004 3.0i got put on a diagnostic machine and it says that lambda 1 and 2 are faulty is that the 2 lambdas on my manifold it also says misfiring on 3 and 5 the man at the garage says the lambdas could cause it to misfire true or false help please
cheers davie

[AW8]

Lambdas are oxygen sensors. I don't have a 3.0i but on mine there are Lambda sensors before & after each of the 2 catalysts.

I don't know exactly what help you are seeking. If they are faulty they need changing you just need to decide whether you are dong this yourself of whether you will pay someone else to do this. if defective then there should also be a yellow SES/CEL lamp illuminated on your dash display.

Are you asking exactly where your O2 sensors are & how to source & change them yourself ?


If starting a new thread seeking help then maybe include the subject matter in the title. This will maybe yield better responses & help others who later search.

[cauf41]

im replacing them but want to know where 1 and 2 are as there is 2 on the manifold and i think 2 down beside the cat

[AW8]

Look at this clicky

This indicates there are 4 sensors made up of 2 of each part number.

It doesn't number each of the sensors thus I don't know if 1 is most forward most & 4 is rearmost.

In terms of numbering of cylinders..... 1 should be at front pulley end & 6 to the rear.

Ideally the fault codes for O2 sensors on yours assuming 4 failures of all sesnors from physical pulley end front of engine to rear should read something like.....

Precat Sensor Cylinder 1-3, ( part 1 in diagram), Postcat Cylnder 1-3,( part 2 in diagram), Precat Sensor Cylinder 4-6,( part 1 in diagram), Postcat Cylnder 4-6.( part 2 in diagram),

I really must emphasise I am not talking from experience but rather from my understanding & interpretation.

I suspect for those of us not used to changing these that access could be awkward.

HTH

........Perhaps grown up will be along to advise you & clarify matters better than I have

[AW8]

Just to add that good technicians & mechanics may be aware of other issues that can cause a code to show. Sometimes a fault elsewhere can cause a problem to show as something else. Not the best explanation but just saying that reacting to all codes literally & with a plug & play mentality isn't always best & can be costly.

[cauf41]

thanks for the advice on the print out it says fuel trim bank 2 and fuel trim bank 1 and the man at the garage said its the lambda sensors 1 and 2

[stevox5]

Hi there

If you have fuel trim errors on both banks ie bank 1 is cylinders 1,2,3 and bank 2 is cylinders 4,5,6 on your brief description this would probably indicate a weak mixture due to an air leak.
Possibly the intake boot from the air mass meter to the throttle body on the small diameter pipe to the idle valve, or a breather pipe running along the top of the inlet manifold or possibly the crank case breather valve . It is very unlikely that the oxygen sensors are at fault.
Fuel trim faults indicate the engine management cannot adjust the fuel ratio correctly due to a problem.
I would get it checked out by a specialist with BMW knowlage to pinpoint the exact problem before throwing any parts at it.
Good luck.

[cauf41]

thanks for all the advice check for air leaks tomorrow
cheers davie

[cauf41]

hi stevox5
you were right the intake hose to the idle valve is split will go to bmw on monday for a new 1 thanks to every one for there advice
cheers davie

[stevox5]

Glad you found something mate , the boot is about £12 .
It's awkward to fit as the jubilee clips on the throttle and idle valve are hard to get to but with a little patience it's not too bad.
Once replaced if you have a diagnostic kit to hand it would be a good idea to clear the fault codes and reset the fuel trim additions.
Good luck.

[cauf41]

thats the boot fitted really awkward to get to the jubilee clips but managed get the faut codes cleared tomorrow cheers again stevox5