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Hi Guys

A-Class 140, 2001, 69000,

Hope for some help,

Fault code P0170 only

Ran diagnostics as follows at operating temp

Maf, air flow 1.5 g/s at idle, around 5 g/s at 2500. It has been refurbed recently.

STFT almost always lean ranging -1 to -10
LTFT mostly +27
pre cat O2 sensor all over the place from .1 to .9

Have checked for vacuum leaks, none as far as I can see.

Have a donor vehicle same age. swapped o2 sensors, coil pack, fuel filter.
Have fitted new plugs and air filter.


John
 

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A160 W168 /2002
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john,
who refurbed the MAFS, sounds like it needs checking if it was BBA reman they were fitting an ajustment screw to their early repairs not sure what their doing these days, and I sooner not know,
if it was ECU testing get back to them under the lifetime warrantee they will check it out, make sure the security seal is unbroken on the ECU they can test bed the unit
 

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I have also had the P0170 code thrown up on my 2002 A140 Auto and now the car wont run.

I jet washed the car, not the engine bay (not sure if this is to do with it). Drove the car just after for around a mile or so with no issues. After that it became sluggish when pulling away but was then fine at normal speed/higher revs

It gradually got worse until the point where it died and will now turn over and occasionally pick up but then stall

I know that all of this symptoms point towards MAF/ECU but if this were the case would it come on so quickly and die in this way, it has been running fine with no issues previously?

Has some water got into the o2 sensor and shorted it or messed it up causing it to screw up the mix?
I got the RAC out to have a look and although he couldnt fix it he seemed to be of the opinion it could be the o2 sensor

Is it worth changing that first off before sending the ECU of for testing? Does the o2 sensor plug in underneath the car near to the CAT or does the wire run further up into the engine bay near the ECU etc

Sorry for the long story and hopefully someone can help

Ta
 
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