I replace the MAF sensor with a new Bosch unit, and also the air filter element, and I still get intermittent P0100 codes, I can reset the code and it will set again within 10 minutes of driving. I have cleared it about 5 times. Is there anything else in the intake system that could be causing it? Before I replaced the MAF sensor the code was always set, now it's intermittent. The performance improved after replacing it though.
I replace the MAF sensor with a new Bosch unit, and also the air filter element, and I still get intermittent P0100 codes, I can reset the code and it will set again within 10 minutes of driving. I have cleared it about 5 times. Is there anything else in the intake system that could be causing it? Before I replaced the MAF sensor the code was always set, now it's intermittent. The performance improved after replacing it though.
Thanks,
Cameron
San Diego
Hi, Cameron.
Just curious from your description, did you replace the whole MAF assembly or was it just the insert like the guy sells on e-bay?
Are you getting any other codes? Sometimes if you've driven long enough with a recurring/intermittent problem you can damage other things, most often these should also result in a code, with or without the CEL.
If you haven't done so it's probably worth pulling your intake ahead of the MAF and being sure it's clean, that the airbox is clean, and that the intake to the airbox is clean.
Take care and enjoy the ride,
Greg
__________________ If the only prayer you say in your life is thank you, that would suffice. Meister Eckhart
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I replaced the whole assembly with a matching Bosch part # that MBZ specifies. There are no other related codes, just a pending P0460 fuel level code. The air intake tract looks clean, no holes, and the upper airbox half looks like it's sealing on the air filter element properly.
Just to test I reset the hard P0100 code and ran it for a bit (past warmup), then it set a pending P0100 code, so then I drove around about 10 minutes with stop/go, surface streets up to 60mph, hills, with and without stop lights. During this time I was reading codes, and then resetting them while driving, but the next cycle of the code reader would see the same pending code, no matter what I did, with no grace period.
When I got home, just to test, I unfastened the airbox and lifted it enough to "simulate" a large air leak on the inlet side of the aintake, and it didn't produce a hard code, only the same pending code.
Likely when the car is cold again, and the idle surges enough it will hard code again. Will it pass smog with a pending code?
I replaced the whole assembly with a matching Bosch part # that MBZ specifies. There are no other related codes, just a pending P0460 fuel level code. The air intake tract looks clean, no holes, and the upper airbox half looks like it's sealing on the air filter element properly.
Just to test I reset the hard P0100 code and ran it for a bit (past warmup), then it set a pending P0100 code, so then I drove around about 10 minutes with stop/go, surface streets up to 60mph, hills, with and without stop lights. During this time I was reading codes, and then resetting them while driving, but the next cycle of the code reader would see the same pending code, no matter what I did, with no grace period.
When I got home, just to test, I unfastened the airbox and lifted it enough to "simulate" a large air leak on the inlet side of the aintake, and it didn't produce a hard code, only the same pending code.
Likely when the car is cold again, and the idle surges enough it will hard code again. Will it pass smog with a pending code?
Thanks for the insight,
Cameron
San Diego
Hi, Cameron.
That's interesting...which year/model is your 210? I can tell you when I had mine smogged up in S.F. they didn't plug in a code reader; here they just look at the dash, if the CEL is lit it's auto-fail, if it's out they run the normal tests. So unless you have an active CEL (or whatever is causing the surging is pushing emissions beyond tolerance) you should be fine.
The surging is what's more interesting. Have you checked for vacuum leaks? Those are a common cause, and don't forget your brake booster in the list. I don't know if your description of surging could be described as intermittent irregular idle, almost a misfire, but if so then it could be a faulty CPS. A faulty TPS could cause "surging", but those almost always trigger a CEL whereas the CPS almost never does (don't even bother asking the all-important why question...) The good news is you're not getting codes for O2 sensors, those are a little on the pricey side, particularly with the V6 and V8 models.
If you're up against the wall re: test deadline, I'd drive it around so it's nice and warm, if you get the CEL light then reset it and do a drive cycle, then when you take it in all should be good. If you fail you can then pursue the cause of the surging but will have more time to do it. Take it to one of the places that does the free retest just to be safe.
It's a 98 E430. It seems when the surging around idle starts that is when the hard code gets set. Yes, it almost seems like a misfire, but only at times. I've measured the voltage going to the MAF pins 2-3 and it's 12.0V, so I guess that's fine, I've also checked the throttle position, and it's at the stop at idle with slack in the line, and also moves smootly to WOT and hits the stop there too. I took the entire intake tract off and looked for problems, but everything is clean and looks okay. I reassembled, then ran the engine while spraying WD-40 all over the intake system, and also any other vacuum areas, and the idle didn't change at all, or the engine run any rougher, like it normally does with an intake leak. How would I check the CPS?
After much screwing around, I order another MAF, installed it an it works great! BTW, this time I just replaced the insert (stock Bosch part#) and not the tube assembly, basically for $100 + shipping, now it happily passes smog...thanks for all the help
After much screwing around, I order another MAF, installed it an it works great! BTW, this time I just replaced the insert (stock Bosch part#) and not the tube assembly, basically for $100 + shipping, now it happily passes smog...thanks for all the help
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