Mass Air Flow Sensor Code

Mandrake · Post by **Mandrake** » 04 Apr 2009, 06:44

On my 2001 S60 T5 the check engine light came on recently and I brought it to a local shop to have the code read. He told me that it was a code for the air/fuel mixture in the mass air flow sensor. I have already had the throttle body replaced I believe at 88k miles I now have 146k. I was going to just spend the money to buy the Air Flow sensor and replace it myself. I was wondering if I could just replace the Intake temperature sensor in it or if I had to replace the entire unit.

Also I am starting to hear a slight whining/grinding noise coming from the passenger front wheel while coasting at about 35 mph. When at a complete stop I get a slight clunking noise when starting off again. The whining/grinding goes away during acceleration and braking. I'm thinking the wheel bearing is starting to go bad.

Any suggestions will be much appreciated, Thank you, Mike.

vlvman · Post by **vlvman** » 04 Apr 2009, 19:38

No, you can not replace the temperature sensor within the MAF. You can clean the electrical contacts and connector on the MAF with electric contact cleaner, after cleaning apply a small amount of dielectric grease to the plug to prevent moisture from getting to the contacts. then have the codes cleared at an auto parts store for free. If the car runs good I would try this before replacing the MAF. If the car runs bad try unpluging the electrical connector to the MAF while the engine is idling if it idles better with MAF disconnected than you need a new MAF.

You can check the wheel bearings by jacking up the car and placing jack stands under the car. Then grab the wheel at 12 oclock and 6 oclock and rock the wheel checking for play in the wheel bearings, note play in other parts will show with this method also so you have to look for the source of the play while rocking the wheel. Also spin the wheel and listen for bearing noises, you may have to move the brake pads away from the disk to confirm the noise is the bearings and not the brakes.

vlvman · Post by **vlvman** » 04 Apr 2009, 19:42

After rereading your post I would also check the brake pads for wear, as you may need new pads.

Mandrake · Post by **Mandrake** » 08 May 2009, 07:15

I thought I wait a while before I posted a response, just to make sure everything was fixed. As far as the MAF code, I replaced the Air Mass meter, cleared the code and I haven't had a problem since. The whining grinding noise looks like it was coming from the wheel. I am still at a loss of what exactly was wrong but I rotated the wheels and the noise has been gone since. The tires are all evenly worn and no cupping on any of them so I'm unsure why this made a difference but it did. Thanks for the help, Mike.