what is a map sensor

alice · Post by **alice** » 04 Sep 2010, 17:51

my 2003 v70 2.4 non turbo has a code that is map and the check engine light has come on twice. mechanic trouble shot the check engine light and the code map came up he cleaned out a hose and then turned off the check engine light.. It came back onto today.. I also have a roaring like a muffler almost sound a rough sound and only when I excelerate (foot on gas) are these connected???? i.e. check engine light/map/and the sound like an exhaust problem almost.. its not as bad as the noise of a bad muffler this is just my limited discription of the sound and feel.. Thanks for any education on this matter!!! Alice

Post by **JDS60R** » 04 Sep 2010, 20:05

Map sensor is a manifold air pressure sensor. They go bad over time and is a well known failure part on Volvo.
We change them around 60-80K as part of a full tune up on a turbo car. ( if it fails on a turbo it can hurt the motor or put it into limp mode)
It measures the vacuum or pressure in the intake to detect turbo boost and the load the engine is under. Non synthetic oil usage helps it to fail early (synthetic have lower burn off percentages). It is easy to change (2 screws)

smarzig · Post by **smarzig** » 10 Nov 2010, 10:31

Engine Performance problem
2002 Volvo S60t 2.4l 5cyl Front Wheel Drive Automatic/Trip 197000 miles

Hello. Recently my serperntine belt snapped due to a sezied AC compressor. The local shop changed the ac/pulled (which also got rid of the loud winding sound). Well the car runs GREAT around town except that when i step on the gas i get no kick at all. it will eventually get to 60-70 mph in about 20 -30 seconds but when i press down, nothing really happens except smooth and steady. I took it to ANOTHER guy that only fixes up volvo's and he said its not the 1k part that always goes, but 2 cheaper parts but he couldn't tell which. I think he said pedal sensor or 1 other part. Around town and (eventually) on the HW it runs great, no rough idle or antying except the Cruise wont engage. I could get the codes at autozone around the corner if that helped. I seriously have this feeling its the MAP Sensor. Rock autoparts has one after market for 45 and FCP has one for 90. Thoughts? I would seriously appreciate your help. Did driving around town w,out the belt (to find a belt) or them changing my belt/ac do something? help

stuartg3 · Post by **stuartg3** » 13 Nov 2010, 17:14

Have an issue with my wife's '03 V70, 2.4 non-turbo. She started complaining about a loss of power about 6 weeks ago. There was no "check engine" light, no rough idling or anything obvious. Matter of fact, if you were driving without getting too far into the accelerator you would never know anything was wrong. When you accelerate hard or try to climb a hill, the engine lacks power. The trans will downshift, the revs will climb, but no corresponding increase in power. If you hold the accelerator down the engine will start surging, like maybe it's starving for fuel.

Up to this point the car has always been serviced at the dealer or authorized shop. Car has 120K, fuel filter was changed out 5K ago, timing belt replaced 15K ago.

I was looking for answers and was reading about MAP and MAF sensors on this forum and others. Are they the same? I saw where someone referenced this forum and alluded to a test procedure for determining whether the MAF was bad. He unplugged the MAF while the car was running and because the car did not die, determined that the MAF was faulty - does that make sense? Wouldn't a faulty MAF turn on the check engine light? Also read where someone had 2 bad coils, again - wouldn't that turn on the check engine light? How do you Ohm out a coil (which of the four leads)?

I appreciate any help,
Stu

jda2000 · Post by **jda2000** » 13 Nov 2010, 17:29

MAP and MAF are 2 different things.

If you disconnect the MAF sensor and the car idles better or the same, then the MAF is bad. When a working MAF is disconnected, the engine usually stalls and dies.

stuartg3 · Post by **stuartg3** » 13 Nov 2010, 18:47

So I disconnected the MAF while the car was idling and the idle got rough for a second and then smoothed out. When I replugged the MAF, there was no noticeable change. I guess that means that I've got a bad MAF? Wouldn't I have gotten a check engine light? What about cleaning the MAF - is there anything to that?

Thanks again,
Stu

jda2000 · Post by **jda2000** » 14 Nov 2010, 16:36

the MAF could be failing, thus no CEL light yet.
Try cleaning the MAF sensor, sometimes it works.

If you know another volvo owner, try swapping MAF's to see if there is a difference.

smarzig · Post by **smarzig** » 15 Nov 2010, 08:16

what Stuart is describing is EXACTLY what I am experiencing as per my post before his.
Can anyone tell me WHERE the MAP Sensor is? Sorry there seems to be alot of sensors.

CAn someone link a pic?

also where is a good place to buy this? FCP?

Post by **jblackburn** » 15 Nov 2010, 09:18

On an S70:

The same part is listed for the 2001-2002 models, but the location might be different.

http://www.fcpgroton.com/product-exec/p ... 99-2002%29

smarzig · Post by **smarzig** » 15 Nov 2010, 09:57

thanks. ok now where is MAF sensor which is where it looks l should check.
Is this pic it? (p.s. MAF/MAP is confusing)