I have a 2000 S40 which has been running rough lately. The dealer told me I need a new MAP sensor. Could anyone tell me where this senor is located? I'm not exactly sure. Is it difficult to replace?

Also, I've had an intermittent problem with the idle speed dropping and engine stumbling at stop lights. The engine will hesitate on acceleration, but then runs fine. Could the MAP sensor be responsible for this, or is there another problem to fix? Thanks for the help.

 

Yes that could be causing all your running problems.
The Map (mass flow sensor) is located on the air filter housing.
It has a plug going to it and the hose from the air filter houseing runs from the mass flow to the engine.

 

Thanks for the quick response. I just want to make sure I understand. I thought the mass flow sensor was the MAF, and there was a different sensor called the MAP for manifold pressure. The dealer said I need a new MAP. I did see the sensor you mentioned on the air filter, but I want to make sure I'm looking at the right one.

 

Depending where you are is what the exact term is.
The MAP sensor is on the older cars that don't have the MAF.
Volvo calls it a map/massflow sensor.

 

I was able to locate the MAP sensor (on the firewall), and I found that the vacuum hose was not connected to it anymore. The dealer apparently didn't check this. They just told me I needed to order a new MAP sensor. I wasn't able to locate the loose end of the hose though. Maybe it has fallen off completely. Do you have any idea how this hose would be routed on a 2000 S40? I've been trying to trace it back to the engine and find the missing link, but I keep getting lost in the tangle of hoses.

 

Im not sure exactly where it goes but one thing that might help you is to try to listen for a vaccum leak while it is running.Or get your self a can of carb cleaner and spray around all the hoses and if the idle changes then there is where the vaccum line is or there is a leak.

Sorry about not knowing where the map sensor is but I will remember now.

 

I am having a start problem and minor idle prob with my 2001 S40. Before buying the part for $200+, is there a way I can check it, such as taking my MAP off the car?
Besides the recurring check engine light prob, I read a bunch of codes, inclusing Misfire, O2, etc.

 

You might want to start a new thread so your problem does not get confused with the original poster above. (called hijacking a thread )

Search "hard starting" and it should point you toward the Fuel Pressure Regulator.