98 V70XC MAF Voltage Help

Post by **erikv11** » 16 Jun 2015, 08:28

There are very few scanners that reset the service light, and none of them are cheap. Unless you buy one of the modestly priced tools dedicated to the service light reset. The best way to deal with that light is to throw away the bulb, it is essentially useless. Some people also put a little square of black tape over it but that has never appealed to me.

For the ability to deal with the service light get VOL-FCR and a vag-com cable and a PC (cheap, has been posted about dozens of times, just do some searching). Otherwise get almost any cheap scanner. The Harbor Freight ones are popular here.

To check vacuum leaks yourself, you can use an unlit (really!) propane torch or starting fluid.

mika · Post by **mika** » 17 Jun 2015, 14:58

dmcfan wrote:Also sometimes when accelerating the car feels like it hits a wall and the rpms stick and hold then goes back to normal.

I know we are all talking about MAR, but..Worth a look b/c so simple, is the transmission oil low? needs to be checked when hot

dmcfan · Post by **dmcfan** » 18 Jun 2015, 06:49

Well it was looking good for 3 days after doing the tsb the car ran amazingly better but just now the light came back.

I tried to do the voltage testing At the sensor and got 1.1v at idle and it went up with engine speed up to about 2.4v. I believe that is normal.

This may be coincidence but it is more muggy and damp today and that is what it was like the last time I reset the light and it came back.

I really want to believe it is the MAF because everyone since tinkering with it the car has improved. Could it still be bad even with all this data?

Sometimes problems do not make sense but I would think if it was a vacuum line or O2 sensor it wouldn't take 3 days to throw the code again since I never touched them. The MAF has been worked on and the car felt much better after the tsb.

As far as the trans fluid goes that is ok. I recently did the IPD flush kit on it and the levels were good before and after.

dmcfan · Post by **dmcfan** » 18 Jun 2015, 12:08

Since I am fixated on the MAF being it I am going to do the last test I know and disconnect it for a full days commute to see if it stumbles. If it doesn't I will reconnect to see if it does.

Post by **abscate** » 18 Jun 2015, 14:45

The car might be lethargic and mileage will go down but if the stumbling stops you've nailed it. Get the real thing here and be aware the 1/2 Price Bosch in eBay is probably counterfeit

" made in the same factory as Bosch" translates to " won't work" in eBay-mandarin

Post by **erikv11** » 18 Jun 2015, 17:47

Along those lines, what brand of MAF is in there now?

A junkyard (Bosch only!) MAF is cheap and so useful for troubleshooting.

dmcfan · Post by **dmcfan** » 18 Jun 2015, 18:57

It is original. Don't worry I am not an eBay knock off parts type of buyer. I plan on getting a new Bosch from FCP if needed.

If it ends up running ok after disconnected would it be better to run like that until the new one arrives or reconnect and deal with the stumbling. Either way the car wouldn't be running completely normal.

Post by **erikv11** » 18 Jun 2015, 20:38

OK if it is Bosch that is hopeful, the aftermarket ones indeed have a bad track record. You never know what a previous owner might have put in there.

I would probably run it disconnected if the MAF turns out to be the verdict. It will run rich, which hurts fuel economy but nothing else. Plugged in it could stall on you in a bad situation etc. However running rich for an extended period of time can harm the catalytic converter, don't do it more than a few days.

dmcfan · Post by **dmcfan** » 19 Jun 2015, 01:15

It was a one owner car and the had complete service records from the Volvo dealer since 1998. Each 5k service done and anything that needed to be done they had the dealer do. It is still 100% Volvo parts on the entire car. I got lucky with it.

dmcfan · Post by **dmcfan** » 19 Jun 2015, 07:47

Well after a day of the car stumbling more frequently, with the sensor disconnected it never occurred.

I reconnected it and of course it ran smooth today but it has always taken 2-3 days for it to start up again. In am going to replace it and cross fingers. Thanks for the input everyone.

Now if I can just figure out why my two door speakers go in and out the car will be solid.