The service engine light came on in my 2001 Mitsubishi Eclipse (w/53,000 miles). The company I took it to replaced the mass air flow sensor ($770 for parts and labor). The light came back on almost immediately and the company suggested that a tune up might correct the problem ($360). The light came back on a day later. They replaced 2 fuel injector o-rings that were cracked - problem solved. They didn’t charge for the o-rings, so am I right in assuming that the original $770 air flow sensor may not have needed to be replaced? - that the service engine light was due to the damaged o-rings?
That’s a good possibility. Do you have a record anywhere of the actual codes that came out of the process? (These are read out of the car’s computer and are a letter followed by a number such as P0100).
I don’t have a record of the codes. The mechanic named them for my husband over the phone, but he didn’t write them down. Would a code have indicated that the air flow sensor was actually damaged or would it have just indicated it as a starting point.
Codes only give starting points for diagnosing problems - they don’t indicate that specific parts are bad, though they often do point in the general direction of parts. The problem of throwing new parts at things is pretty common. I would ask for a full explanation for the $1,000+ that you threw at them, even though it isn’t likely to get you anywhere. Then I would find someone else to take it to next time.
I can’t see that the shop did ANY diagnostics and testing. If they had, they wouldn’t have changed a good mass air flow sensor. What the shop, most likely, did, was to only use the symptom (the trouble code) to change the mass air flow sensor. This is plain wrong, though a common practice.
By a stretch, if the mass air flow were faulty, Auto Zone Auto Parts has it for $235, plus tax. Tax on the one you bought wouldn’t have been $500. It takes about 15 minuets to change a mass air flow sensor.
What to do with these repair-by-symptoms-only “mechanics”? That’s a very good question.
So what do I say to them NOW - as of this morning the service engine light is back on. I’m taking the car back to Brake Max because there seems to be no other alternative and I don’t want to start at square one. Any suggestions?
Many auto part stores will read the codes and tell you want they are for free. Get them read and bring back the results here. The codes should read like (P0123). They likely will also have an English translation. Bring that as well, but the actural code is more important.
Really? So when a code says “Low voltage to the mass air flow sensor” that doesn’t indicate that part? I must be doing something wrong…
Benzman
Yes, really. This was in there:
“they often do point in the general direction of parts”
Try this one: Random/Multiple Cylinder Misfire detected. Shall we replace the cylinders then?
And note that “Low voltage to the mass air flow sensor” doesn’t tell you why or that you need to change a part. Besides that she doesn’t know what her codes were, and whatever “parts” this place thought the codes said to replace were obviously wrong.
If the same code is coming back, it could be for new reasons, or old. You can demand a detailed explanation, written in standard English from the shop. If you’re not satisfied, or, they won’t do it, there is small (petty) claims court. There are, also, attorneys general consumer affairs that you can complain to.
Well it’s always indicated to me a part was bad. It’s up to your own training and experience to know why low voltage makes a MAF sensor bad.
I can certainly excuse her for not knowing the codes, as they probably don’t mean anything to her. But for the tech to throw $770 at the MAF sensor when the problem was the injector O rings is unexcusable. (At least as far as the info we have)
What directed him to the MAF sensor in the first place? Was it in fact bad in addition to the failed O rings? Again we don’t know. But like you stated, throwing new parts at a problem is not uncommon.
Benzman
I know nothing of Mitsubishis, but the first line of your question caught my eye. Many cars have a Check Engine light and a Service Engine Soon light. You called it a Service Engine light. Is that what the light says?
They are charging you a lot for very little expertise. As noted, and aftermarket mass airflow sensor is less than $300, and their cost if they got the dealer part is only a little over $300. They were paid handsomely for the time it took them to read the code, call for a part, loosen two screws and a bolt and put the new part in. Then to add insult to injury, what the heck did you get for a $360 tune up? I recently ‘tuned up’ my wife’s 2004 BMW - first time the engine had been touched in 62,000 miles. I spent less than $75, and that included a new fuel filter.
At this point, I think they owe you a solution to your problem with nothing more than parts cost on your part (their cost). If they won’t do that, don’t ever set foot in there again and tell your friends.
So here’s the newest twist to the mass airflow sensor debacle. In between replacing the first one (which the mechanic assured us was damaged) and replacing the o-rings, the brand new was damaged by the bad o-rings. Now he will be replacing the new mass air-flow sensor with another new one at no cost to us. I did get the current codes from him - P0170 and P0173. I won’t get the car back until Friday because the only Mitsubishi dealer in our town closed this past Monday so he has to get the parts elsewhere. The no-charge makes me happier, but should I feel any better about the whole experience now? By the way, the light says “service engine soon.”
It still smells like the shore with a landward breeze. “DAMAGED”(?) mass air flow sensor?! Damaged by WHAT? A screwdriver? A fuel leak “damaging” a mass air flow sensor?! What would Ray’s response be to that?
It’s the law that you can have your old part. Some places, I understand, you have to write on the repair order, “I want the old part”. I don’t know about your locale. If you can get it, check its part number and have a trusted mechanic examined it. {I realize that you may get a mass air flow sensor which has been set aside for such a time as this.} Besides, you’ve already paid enough for TWO mass air flow sensors.
Going back to this shop will bankrupt you. Clearly these people are throwing parts at the problem at your expense.
If it’s truely the “service engine light” then you need to get the routine service performed and the light reset. Your owner’s manual may even tell you how to reset it. If that’s the case, they simply took you for a ride.
If it’s the Check Engine Light, then they don’t have the diagnostic expertise or perhaps the desire to actually diagnose it and fix it.
Lots of things can trip a CEL. Codes are not that definitive, just head the tech to the right area without going down lots of blind paths. Much as a physician who finds an irregular heatbeat must then do more tests to further define why, the technician often has to do further analysis to find out why a signal is erroneous.
Go elsewhere.
Does someone know what the codes P0170 and P0173 indicate?
mass air flow sensor?! Damaged by WHAT?
Maybe a K&N filter?
They’re both “long-term fuel trim” codes (left and right bank). “Long-term” just means they’re persistent, as opposed to just transient. Very generally, they indicate an air/fuel mixture imbalance that could be caused by fuel metering problems or air metering problems. Sometimes it can be literally understood to mean that the mass of the air, as measured at the MAF sensor, is not the same as the mass of air as measured when it has reached the intake manifold. That could indicate an air leak somewhere inbetween.
An air metering problem can have many causes, including a MAF sensor, heated oxygen sensor, cracked PCV hose or crankcase pressure control diaphragm, cracked cam cover breather hose (also part of the PCV system) and I’m sure I’m forgetting something else. Oh, right: Cracked fuel injector o-ring. Check all clamps, connectors, and hoses. If there is a PCV pressure control diaphgram, check it for cracks. The MAF sensor is a sensor. Ergo, if it is not broken and you have an air leak, then it is supposed to warn you.
Sometimes a mechanic may believe the cheapest and fastest course of action is to keep throwing solutions at the car until one sticks. It’s a shame, especially since you still have an air/fuel metering problem or a leak.
The check engine light will turn on in response to anything that may affect tailpipe or evaporative emissions. Hope this helps at all.
So, bottom line, can cracked o-rings damage the mass air flow sensor?
“What would Ray’s response be to that?” It would be, “Bo-o-o-o-o-gus!”.
NO.