Manager Forum

I'm having some trouble with a customer's CL500. We originally had this car come in 6 weeks ago. Mercedes dealer diagnosed for a bad MAF. Scanned for codes, P0170 and P0173 were present. Removed and replaced MAF with another sensor. Vehicle returned for same issue approx. 2 days later. Same codes present. Value of MAF v at KOEO was 1.42 and out of range of the normal .980v-1.030v range. Acquired another MAF and replaced. We also noticed upon replacement that the seals at both ends for inlet and outlet of MAF were hard as a rock and leaking air- removed and replaced with new ones. Checked initial voltage readings with KOEO, and they fell within specs. Returned vehicle to customer. After a few more days of driving, customer returned with same 2 codes again. Taking readings of KOEO voltage of MAF, we now get 1.06v (out of specs again). Smoked system and found no leaks with the exception of EGR valve (before and after driving), unless vacuum applied (then system is completely sealed). No excessive engine wear detected, intake sealed, injector timing within specs, and no other obviuos defects found. Can someone tell me what else I may be able to do?

were are the maf coming from? OE? New? gotta be a bad one again. I dont work on mercedes but it isnt with in range it is defective. Is anything getting on the sensor? Just ideas

These are aftermarket sensors. Cardone parts. I believe they are new. The part number for this specific application comes down to a 74-10104. Could it be that I need an OE or could something else be affecting these sensors after installation. No foreign materials have been found in them, and cleaning them out after they came back and failed both times did not help any of the readings.

Those cardones are rebuilt sensor and are garbage.ssorry. there is no way to rebuid a maf sensor. Sad to say but yes you gotta go oe. They are not actually rubuilding those sensor im almopst positive they are just taking them apart and cleaning them then gluing them back together. been there done that on another vehicle

oh and file labor claims for each defect including diagnosisso you may be able to cover the price difference

along with replaceing it with an oem i would see if there is a leaf or something along those lines in the air tube between the maf and air filter. had a gm years ago with a similar problem and there was an oak leaf that would get sucked up against the protection plate cutting the air flow down and sensor was overheating and burning up. yep another of those oddities that made me loose more hair. right up there with the car that had a strange noise in it. after killing myself looking for the noise i finally dropped the gas tank. inside there was about 5lbs of gravel and about 100 marbles. 5 year old son........................................

Does anybody actually get paid for the warranty claims they file?

yes

yes 100 % of the time.

i'm like a klingon on a blood scent when i file a labor claim. i put them in a file in the lower drawer of my deck and make weekly phone calls to check on the claim. i swear that the manufacturers intentionally drag their feet hoping you'll let it slide. on a benz i believe there are more issues than a maf sensor that can cause the code. the timing sounds right for the light to come back on. i know a intake leak can cause this problem and i think an o2 can as well. it's been a while though since i've worked on one of these. if this recently had work done on it in the wiper cowl area i'de look at the harness where it runs through the top of the firewall and along the top. i've seen the harness cracked in a few differant places. one time i had one so badly damaged i would have thought it was used to lift the car with a chain fall.

Any news?

It took forever to get the computer back up and running in my office after remodeling and switching over to COX comm., but I'm back. Yeah- I had a heck of a time trying to get that MAF to work, but found out that the O.E. one works like a charm and fixed all our issues. Do yourselves a favor- when it comes to sensors and you have a euro-vehicle, go O.E.!!! Had a 323 BMW a week later that had problems with a camshaft pos. sensor. Got a standard motor products brand part (looked very slightly bigger), and installed it. Then we had all sorts of codes being thrown into the ECM. Got a BMW one after 3 days of chasing our tails, and voila! Problem solved. I've learned my lesson.

Oh Yeah, by the way- I got 2 labor claims pushed through the aftermarket parts store paid in fulld as well as the fees for acessing Mercedes-Benz's technical database online for 2 24 hr. periods. For only $18.00 a day, its worth it for the info they give you.