Customers 60,000 mile wagon has a freon leak and was pressurised by MB of OKC last autumn.
The EC symbol 'red' lamp is on when commanding a/c.
Snap On scanner Mercedes cartridge does not communicate with
a/c, but it does read a/c command request which reads OFF.
I found system had 25 psi static pressure and added to 85 psi from 30 lb bottle but still no a/c function. Also noted the FAN will occationally change speeds slowly and erratically and sometimes go from slow to med and back again with no input , display does not change during this system quirk.
She tells me MB of OKC also installed a new push button facia module last year for same problem.

Futher more I recorded many engine P codes as CHECK lamp was lit. They where as follows in order listed.....
P2085 Part Load Fuel Trim Bank 2 limit.
P2016 Ditto, Bank 2.
P2017 Idle Fuel Trim Bank 1 Limit.
P2086 Ditto Bank 2.
P203E No/Incorrectmessage from I C.
END.
I cleared codes and none returned on teat drive of 5 miles.
I did notice post cat bank 2 O2S was not ranging but staying at 0.71 while Bank 1 ranges from 0.002 up to 1.096. which seems O2S 's are begining to fail. Post cat sensors ranged okay only after holding rpm's to 3000 for 2 minutes.
Noticed that adverage fuel milage was recorded at 14.6 mpg on test drive. Seems a little low to me. She says usual mpg is 20 plus.

Seems I might be quoting her for O2s , what is your take on all this ?

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Look hard at the a/f meter. The 112 engines are kinda hard on 'em and they are less expensive than O2's.


On the ACC with a leak and a ec light flash I'd check the refridgerant temp sensor in the dryer for function. I'd also find something that'll check the codes, the ACC panel is capable of displaying these but, I do not have the procedure, search around on the net, I'm sure its out there. (I've got a sds, dont need that)

The MTG2500 should read the air flow sensor in hg, if it will the car should idle around 16 and hit 350-400 momentarlily on the rev limiter. The rev limiter is also a pretty fast cycle (about as fast as the "no fault flash out" on a Lexus Trac or ABS system on the early cars.) If it's lazy on the limiter and while driving it fairly briskly its feels like it has a slight surge on accel definetly give the air flow meter the hairly eyeball and check the intake air horn for broken clips and or leaks.


Ignore the IC code, thats pretty much normal. Which code has the freeze frame data for it? Thats the one that set the light and is the first on to try and fix. The rear o2's should be pretty stable at around .450 v, the fronts will cycle from .2 to .8 fairly quickly. (the 2500 is too slow of a interface to realy see the cycle accurately)

The 112 ME2 mills aren't too difficult to work with and are pretty forgiving with the excetion of the trim codes and occassional o2 codes for a/f meters. When you replace the meter be sure to let it idle awhile for readjusting the self adaptation and then drive the **** out of it for 10-15 miles to finish the job. Either that or find something capable of resetting selfadaptation stand alone, it'll run "funky" at first with a new meter.




Joe

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Project Smoker, '87 603 powered wagon
Hauler, 96 CTD can you say torque?
Toy 73 Cougar xr7 convertible
Acme Automotive Inc.
Raleigh NC
919-881-0364

If the "Economy"light stays on with all functions except Defrost, check out my similar problem at 210 chassis climate control problem

Len

Must say, Thank You, to both for your valuable input, 'Knowledge is power" as they say.

I will consult with my MB parts dept' on Monday. My customers parting comment on Friday was...." ...will it be another 4 to 5 thousand dollars or so Don?..."
My reply was ....'Shouldn't be"

With this in mind, I think I might replace Temp/Pressure switches and also the Temp' probe in the Evap' housing and follow this with the re-programming with the Push button Unit

Will try to remember to update this post with the 'FIX'

__________________
[http://languageandgrammar.com/2008/01/14/youve-got-problems-not-issues/ ]

"A liberal is someone who feels they owe a great debt to their fellow man, which debt he proposes to pay off with your money."

Replaced the temp' switches and the AFM.
Car came back to do this a few months ago now...sorry about the delay in updating this.

She says the car runs well, has normal cooling and fuel consumption has got better at around 20 mpg.

Thanx again folks.........

__________________
[http://languageandgrammar.com/2008/01/14/youve-got-problems-not-issues/ ]

"A liberal is someone who feels they owe a great debt to their fellow man, which debt he proposes to pay off with your money."