E46 330Ci Engine Warning Light
Discussion
This came on. Engine felt a bit hesitant at low revs. Otherwise ok (except for the flipping pinking which won't go away).
Garage did diagnostics and replaced a coil pack and lambda sensor. All ok for 48 hours...but now it's back.
Garage thinks it might be the cats but at a quoted £1200 (which sounds a rip off) I'm not keen to try unless I'm convinced that's the problem...which I'm not.
Never heard of this problem on the forum so would be happy to hear from someone who has experienced this.
Garage did diagnostics and replaced a coil pack and lambda sensor. All ok for 48 hours...but now it's back.
Garage thinks it might be the cats but at a quoted £1200 (which sounds a rip off) I'm not keen to try unless I'm convinced that's the problem...which I'm not.
Never heard of this problem on the forum so would be happy to hear from someone who has experienced this.
I'm on my second replacement set of coils and they've always been genuine BM parts. The garage was able to recover the cost of the coil under warranty.
The car hasn't been back to the garage (a BMW specialist) since the problem re-occurred but I'm not optimistic they will able to pin point the problem.
I've never heard of cat problems on the E46 so that is a real concern.
The car hasn't been back to the garage (a BMW specialist) since the problem re-occurred but I'm not optimistic they will able to pin point the problem.
I've never heard of cat problems on the E46 so that is a real concern.
Off the wall suggestion - Have a quick check of the two section rubber hose/ducting between the MAF/airbox and throttle body.
Common for them to split or crack, causing unmetered air to enter the engine.
Mine had a large split on the underside - and gave a similar feeling of slight vagueness/hesitation at low revs (sometimes made it hard to pull away from junctions smoothly). It also occasionally triggered the engine management light for short periods of time.
If you do find a leak, you'll notice with the engine running that when you cover it up, the idle RPM changes immediately.
Common for them to split or crack, causing unmetered air to enter the engine.
Mine had a large split on the underside - and gave a similar feeling of slight vagueness/hesitation at low revs (sometimes made it hard to pull away from junctions smoothly). It also occasionally triggered the engine management light for short periods of time.
If you do find a leak, you'll notice with the engine running that when you cover it up, the idle RPM changes immediately.
You could try taking your oil filler cap off and giving it a good clean making sure it s on fully tight. Had the EML come on my 330ci Convertible and just could nt find the reason why at all, turned out it was the seal on the oil filler cap , I had nt turned it on closed fully . Anything that lets in excess air to the engine will cause the EML light to come on .
Edited by verbarthe on Sunday 26th October 21:15
Yep check the intake boot shown as an un-metered air leak will create an excessively weak mixture thus causing engine knock along with the engine light on because the oxygen sensor wont be able to command the ECU to supply enough fuel (and the ECU will see this lack of response/feedback) quite easy to read out if the live data is studied by someone who is able to interpret whats going on and why
Edited by Sardonicus on Sunday 26th October 21:38
Thankyou to all for your help.
Back from garage. Fault codes show 'Catalytic converter efficiency' for both banks 1 and 2. Fault codes reset but will no doubt reappear in a day or two.
Cost of two replacement cats c. £1,250 incl fitting. Yikes.
This doesn't seem like a common problem for E46s. Car is not used for short journeys and always run on good quality super unleaded.
I will have to speak to a cat specialist to see if either the cats can be cleaned or there is a lower cost replacement available.
Back from garage. Fault codes show 'Catalytic converter efficiency' for both banks 1 and 2. Fault codes reset but will no doubt reappear in a day or two.
Cost of two replacement cats c. £1,250 incl fitting. Yikes.
This doesn't seem like a common problem for E46s. Car is not used for short journeys and always run on good quality super unleaded.
I will have to speak to a cat specialist to see if either the cats can be cleaned or there is a lower cost replacement available.
I keep getting this, just on bank one though.
Swapped around the coil packs, as the fault originally said miss fire on number 5.
I then checked the intake system, and replaced the DISA valve.
I was going to replace the lambda.
My car runs perfect, except for one thing, start it from cold and after a minute it will start to run really rough, start from cold and drive away, no problems.
Where I am now is the yellow EML will come on after 3 or 4 days of driving, code p 420.
Swapped around the coil packs, as the fault originally said miss fire on number 5.
I then checked the intake system, and replaced the DISA valve.
I was going to replace the lambda.
My car runs perfect, except for one thing, start it from cold and after a minute it will start to run really rough, start from cold and drive away, no problems.
Where I am now is the yellow EML will come on after 3 or 4 days of driving, code p 420.
The car is Now going really well since replacement of the dodgy coil.
Passed its MoT last month no problem so assume emissions ok.
Garage advises that further degradation of the cats will lead to progressive loss of performance - but this isn't evident at the moment.
Passed its MoT last month no problem so assume emissions ok.
Garage advises that further degradation of the cats will lead to progressive loss of performance - but this isn't evident at the moment.
Edited by Argybargy on Wednesday 29th October 23:23
I've been having trouble like this for a few months now. Two lambda sensors and a replacement cat later, the engine light still comes on, usually after a 1 hour drive. Idle is slightly rough at times and when the light comes on the engine feels flat and lacking power.
I've got an OBDII cable and INCA software so I can read the codes and clear the faults but don't know what to look at next. I'm beginning to think the lambda sensors were never faulty and it's something else which hasn't been diagnosed yet.
I've got an OBDII cable and INCA software so I can read the codes and clear the faults but don't know what to look at next. I'm beginning to think the lambda sensors were never faulty and it's something else which hasn't been diagnosed yet.
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