Exhaust emissions warning light

PALEXZ4

Member
Hi,

Seen a few posts on this but I have had a slightly different experience to most posters on the various threads.

Exhaust emissions warning light came on one morning on my drive to work, had only had the car for one week, and had passed MOT the week before that. No change in the way the car was driving except may be slightly worse fuel consumption.

Consulted the forum posts to get an idea of probable cause, came to conclusion it was most likely Lambda sensor, and shouldn't be too much trouble to get fixed. Cause could have been anything from change of fuel to general wearing out.

Took car to the local BMW stealer, paid for diagnostic check and got a nasty surprise!

Actual issue was a small crack in the exhaust manifold. Guy said cause could have been anything, and that while 9 in 10 causes of this light tripping were the Lambda sensor, I was obviously unlucky! I also would have been insane to get them to fix as the estimate was circa £1100! I had to drive to Cornwall and back that weekend, and was advised that actually that would be ok as when the engine warms up it should close up the crack rather than expand it.

Car being new I took it back to the garage purchased from, and politely requested their help in getting it fixed. To my surprise they were very helpful, admitted such a fault so soon after purchase was not good and that they would get it fixed but at the garage they use and not at BMW.

One week later popped the car into the garage they use for an afternoon, and they fitted the new manifold (asked to see the old one to check it had been changed!). They said they couldn't really find a crack but that significant soot build up could also have caused the warning light to come on.

So, had the car back for a week now and doing my daily 90 mile round trip commute, car has been great and no warning lights back on. Did notice that in hindsight the engine had a deeper tone on acceleration prior to getting it fixed than after.

No real moral to the story but may prove useful to someone in future when their light comes on!
 
interesting read & more food for the emission light party .
wonder if fuel additives would have helped reduce the carbon build up ?
 
mr wilks said:
wonder if fuel additives would have helped reduce the carbon build up ?

Good point, doesn't seem to be much consensus on the various threads as to how much difference they (fuel additives) make, but probably worth occasionally popping some in as I can't imagine they do any harm, imo probably worth the occasional £5 on the off chance it does help.
 
PALEXZ4 said:
mr wilks said:
wonder if fuel additives would have helped reduce the carbon build up ?

Good point, doesn't seem to be much consensus on the various threads as to how much difference they (fuel additives) make, but probably worth occasionally popping some in as I can't imagine they do any harm, imo probably worth the occasional £5 on the off chance it does help.

i used the Forte diesel treatment in our TDI golf & it cured it from going into limpmode .
considering popping some in the zed just for good measure
 
So a BMW garage diagnosed a cracked manifold, an Indy replaced it but couldn't find a crack! :?
Do these BMW garages make it up as they go along and guess at what's wrong when the EML appears?
 
Lillywhite said:
So a BMW garage diagnosed a cracked manifold, an Indy replaced it but couldn't find a crack! :?
Do these BMW garages make it up as they go along and guess at what's wrong when the EML appears?
Or they use a process of elimination! :headbang:
 
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