P2188........Need help please read Magnets already changed
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https://mbworld.org/forums/c-class-w...t-6-codes.html
So all the magnets are new......the check engine light popped...for some time it would come on and then go away.....so I didn't pay any heed to it....but now it is stable even tried resetting no use.....
please provide input on what sequence of diagnosis should I do......
thankx
Javvy

You need to make sure that the air cleaner is sealing properly on the MAF & that you have no inlet air restriction, clean filters etc. This is not a vacuum leak or you would be running too lean.
I find it hard to believe that you have O2 sensor or MAF trouble at your mileage but I guess it's not impossible.
Please do me a favour & check that you have no broken swirl flap or runner flap linkages on the inlet manifold. Happens on early M272 engines.

appreciate your help Glyn....
javvy
Phister.....for the parking brake the cable was super loose, so loose that when disengaged would not even come close to the ebrake switich and also the switich was dislodged from its bracket......reinstalled the switich and tightened the cable all is good now....
thankx all for the help.
Javvy




Hmm! I'm starting to wonder if we don't have a clogged Cat on one bank or that the EGR circuit is playing up. Why no codes
thankx glyn for all the help.
Javvy
Please help.
Javvy
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Our dilemma here is that we have one MAF feeding/reading both sides of the engine. So fuel trim airflow measured by the MAF will be signalled to the ECU as equal. However we have the post Cat O2 sensor telling us that we are rich at idle on Bank 1. This tells us that we are over injecting fuel to Bank 1 under idle conditions. The question is why?
Possible reasons with above already checked - e.g. manifold controls:
Bad Cat not cleaning exhaust stream or clogged & creating back pressure.
Bad reading from post Cat O2 sensor Bank 1
Bad reading from pre Cat O2 sensor causing ECU to over inject on that Bank i.e. rich.
An incorrect engine temperature reading by the temp sensor but that should effect both Banks equally like the MAF.
The trouble is that all these things should throw codes apart from a clogged Cat condition.
The Best of Mercedes & AMG
javvy
please let me know
javvy

P2187 System Too Lean at Idle B1
P2188 System Too Rich at Idle
P2189 System Too Lean at Idle B2
P2190 System Too Rich at Idle
I think there is some Benz specific coding sitting behind these that we can't read.
This is where a dealer has the advantage. They can try things. So - you either get this car into a Star or if you want to try things swap upstream O2 sensors & see if the problem changes sides or replace the Bank 1 upstream O2 sensor which might be a waste of money. Original problem.
Now that we are getting too rich on both Banks of course the MAF once again becomes suspect as it effects both Banks or both upstream O2 sensors might be bad but mileage is low & they should throw codes. Rich on both Banks means both Cats likely OK. I would start by cleaning the MAF.
Good luck!
Last edited by Glyn M Ruck; Mar 13, 2012 at 05:29 PM.
javvy
Cleaned the MAF but the check engine light still exists and the MPG is taking a dump......from my reserach I found out there are 4 O2 sensors in this car, left/right upstream seams to be swappable, and left/right downstream different types i guess because of the long and short harness.......
Now I dont mind swapping outr the old sensors with new ones.....so from what you are saying I should replace the old upstream sensors both right and left side...correct???
Please advise..
Javvy
Last edited by Javvy; Apr 16, 2012 at 01:03 PM.

I hate spending money without proper diagnosis - but this is where the dealer has an advantage. They can throw parts at the problem
Your choice if you want to keep away from dealers. New MAF or new upstream O2 sensors at least. I frankly in the absense of further codes don't know which to do first. Flip a coin!
looking at the cost for a new MAF v/s New O2 sensor....I would say repace MAF first and then the O2 Sensor........
will keep you posted....thanks for the reply ....really appreciate it.
Javvy
Thank you all for your help specially Glynn, always there for all of us.
Appreciate your help Glynn.
Javvy



