mass airflow sensor; any computer programming needed?

[BerniniCaCO3]

Hi!

A mechanic did a diagnostic and came up with the mass airflow sensor. He pointed it out to me; I'm swapping out the part myself in the next hour.

Is the computer going to know that it has a working sensor now? My understanding is that it falls back on default values as a crutch, while it's not getting readouts. Will it pick up that it has readouts again, now, or should I plan on taking it back to the mechanic to do a reboot?

Finally; I had to drive it 5 hours yesterday. Not much trouble on the highway, but I definitely felt the broken airflow sensor when in stop-and-go. Did I do any engine damage? It smelled a bit, but the temperature never got over 205F; the smell might have just been unburnt gasoline if the engine was getting too much fuel and too little air at times. Should I have the engine checked out?





As an addendum on the question of computer diagnostics. It sounds like, say, your personal computer's diagnostics-- a preprogrammed run of tests makes note of recorded values, spits out some codes, which match up to likely errors.
I was surprised that a 1.5hr state inspection costs $60, where a 1/2hr computer diagnostics costs $100 (at least at the mechanic I used). Almost as much as the airflow sensor I'm replacing, for not that much of their time and no parts!
Is computer diagnostics something I could do for myself? The right software, a manual to make use of the codes it reads out?

[polskamafia mjl]

Reading codes is something you can do yourself, however there is a catch. Over the counter OBD II readers can't read certain volvo specific codes. On the 850's, you need a special Volvo tool to reset the SRS light, read the climate control codes, ect. You can read most codes yourself though instead of paying the ridiculous price at dealers. Also, w/o the MAF your car was stuck in limp mode. The burning could have been ATF fluid. How hard did you drive it in the stop and go traffic? Also, you will find it more helpful if you move your thread to the 850, s70, v70 forum. This one is for the 2001 and newer v70's.

[BerniniCaCO3]

It's a 2001 v70.

After a bit of a farce finding the right five-pointed star security bit to take out the sensor, and then get the right sensor-- there apparently was an overlap in 2001, and I have the older Bosch model and not the newer Toyota-- I got that done today. The car runs *much* better, the rough ride at <30mph is now fine.

I actually just bought it; the seller had service records, including oil every 3k, a more thorough servicing (tune-up?) every 10k, and a transmission rebuild, which I thought highly of; knowing that it would have needed it soon if it weren't already done. He told me that this part needed replacing, and now that it's replaced it's doing better. I can pull these and give more detailed mileage figures if it helps.

However-- now the "service transmission urgent" message has come up. Is this related to the just-replaced mass airflow sensor? I have to say, the car is no longer running poorly, and given the service records, the transmission really shouldn't need urgent service! Unless I was taken for a ride buying this used car, and the seller knew of it! But I pray that's not the case.
I drove it as carefully as I possibly could yesterday, given the MAF repair needed; but I always drive lightly anyway. Accelerate gradually, brake gradually. Better on gas, even if it didn't need the MAF and weren't misbehaving.

Immediately after replacing the MAF, I took it on a 20mile trip. As I said, it works Much better. However, about 15 miles into the trip, the transmission message came up. Nothing changed in how it drove. Could this be related to the MAF? Change the transmission fluid, reset the computer, and it might be ok? Or more ominous? The "check engine light" remains on, for what it is worth. I was warned that that would be the case even after replacing the MAF, that the computer would need to be reset to clear the error code.

Am taking it in Monday anyway-- it's a new car for me, so I want it serviced and had scheduled an appointment Friday already. But I want an idea of what I might be looking at.

[polskamafia mjl]

Your info next to your post says it's a 98 v70 that's why I was confused. That being the case I don't want to give too much advice since I'm only familiar with the 90's era Volvos. I have a hard time believing the trans issue has anything to do with the MAF though. As I said earlier, if you get an OBD II scanner you can reset the CEL yourself, otherwise you have to put up with dealer prices. Finally, w/o any codes for the trans we're all just guessing as to what the problem is. I would suggest you take it into a Volvo dealer, have them reset the CEL and read the transmission code(s). Write down the code b/c you can look it's meaning up in the repair database here. From there people can start figuring what your plan of action should be. Good luck.

[BerniniCaCO3]

Oh! Gotcha. I'd joined this forum when I was looking at a '98 but hadn't bought yet (to ask about it), ended up with the '01. I should change that

Just did a quick search for OBD II scanner, and they're fairly cheap! Any model that you recommend? And, is there anything that the volvo dealer can do for their $85-$100 one-time scan that I can't do with a scanner I bought myself for $30-$180 (that wide price range is why I ask which you recommend, must be a quality range)?

[polskamafia mjl]

I actually I haven't bitten the bullet to buy a scanner; so far none of my repairs/maintenace have required one. As a result I can't really advise you on which ones are good or bad but there is a nice thread about that in the forum somewhere. I would do a search and read up about them here. Yes there are quite a few things that the Volvo scan tool can do that a generic one cannot. I'm a little fuzzy on the specifics but I know that generic readers can't read certain codes and they can't reset the SRS light.