2006 XC70 MAF code with issues

jimpierce7 · Post by **jimpierce7** » 26 Dec 2018, 17:22

Due to my engine light coming on I checked the code and it said I needed a new MAF. So I replaced it. No improvement. So I replaced the spark plugs and too, still no improvement.
Any ideas before I put it in the shop?
Typically when warmed up she runs fine. Initial symptoms when started cold it won't idle up. But keeps running. Runs fine down the road. If I stop and do something for a bit, when I start again she runs rough. Real rough when idling down. But once I'm moving she is ok.

I pull the ground side of the battery to reset the computer. Engine warning light goes out and will high idle when cold until what ever it is goes wrong. Mid warmth engine stopped, when started the first sign is running real rough at idle.

2006 XC-70 Cross Country. About 190k miles. New transmission last February.

Post by **precopster** » 26 Dec 2018, 18:13

Most MAF codes point to a loosened hose or a hose with a split. The clamp around the throttle can loosen or tear the brittle plastic.

Post by **abscate** » 26 Dec 2018, 19:29

The codes never tell you what part is bad. They guide you to how a sub system is operating out of range, from there you diagnose the whole subsystem to find the faultS.....with an s.

If the car has worked fine for years, and then suddenly runs rough, there are usual multiple points of neglect to find and restore.

jimpierce7 · Post by **jimpierce7** » 27 Dec 2018, 06:42

Loose or split hose has become my quest. I'm not real familiar with Volvo. I've had the car almost three years now and love it.
The problem started intermittent. Which was weird as it would go away. Making it hard to chase down.

Post by **mrbrian200** » 27 Dec 2018, 08:21

There's usually nothing wrong with the MAF sensor itself. Virtually anything on the 'air intake side' that would effectively throw the air-fuel ratio off can cause this sensor to meter an incorrect amount of air entering the engine. Under varying conditions the ECU knows within a certain margin what it should be and spits this code when the sensor indicates air flow outside that margin.

If you don't find any loose hose connections get back to us as diagnosis becomes more complicated and may require a good scan tool that shows live data. Some of the potential culprits get a little pricey and/or labor intensive to replace. You'll want to know for sure before trying to replace any of it.

jimpierce7 · Post by **jimpierce7** » 27 Dec 2018, 20:40

So far I haven't found any split hoses. Even simply tried to see if playing with them alters the idle at all. And nothing. A friend mentioned another sensor on the intake manifold that is a MAF as well? I'm going to go look up, if I can, a list of sensors for this car.
The problem is primarily when I first start the car. Stumbling, running rough. Seems to run worse when started after it has warmed up than when started cold in the morning.
As I don't have any test equipment I'm real limited as to what I can test. I have an appointment Wednesday with a mechanic. I just hate having to do that!! The quest continues in the morning.

Misunderstood my friend, it is a MAP sensor he mentioned.

Post by **SuperHerman** » 27 Dec 2018, 22:32

Don't forget to look at your coolant temperature sensors. I have seen on the forum people having similar issues which ended up being a failing temp sensor.

jimpierce7 · Post by **jimpierce7** » 28 Dec 2018, 06:26

Wow. That's crazy but makes some sense.

Is it worth while to get an engine diagnostic done? Like what the do at Pep Boys and other places? Or is it an expensive code reader? Things have changed a bit since the last time I had it done. Like, 1984 I think?

jimpierce7 · Post by **jimpierce7** » 28 Dec 2018, 18:05

Seems I have a highly advanced XC70. Self repairing!! HA! Still going to go get a diagnostic done Monday. Mechanic wasn't in today.
Suddenly decided to be intermittent.

jimpierce7 · Post by **jimpierce7** » 01 Jan 2019, 13:08

and it continues..... Seems not all MAFs are good MAFs. Diagnostic said upstream O2 sensor and MAF were most probable culprits. I'm still hoping to get a good MAF. If I was able to just return the one I got I would and go to Volvo. BUT, I can't. I have my third one coming.
Replaced the upstream O2 sensor. Seems a little better so far. The mechanic told me that my year car can't reset the computer by simply disconnecting the battery ground. So, I'll go see the mechanic again to have the check engine light shut off.
He also mentioned that the timing belt could do this too? That might be one of those labor intensive jobs eh?