Hello everyone,

I'm new to the forum and I've got a problem with my 2000 s40 1.9T, automatic transmission. I've tried to look this problem up on different forums, I'm finding a few people that have had the same problem, however no one has a definitive answer I've got a few ideas but I'm still confused, so I'm posting it here in hopes that someone can narrow down the problem so I don't get cleaned out by the dealership.

A couple of weeks ago, I noticed that it was taking the car a little longer to turn over than usual, but it would still start every time. Then yesterday I took a quick trip to the grocery store (car started fine), and when I came back the car wouldn't turn over. It cranks, but it won't start unless I give it gas. It will die if my foot leaves the accelerator, even when the engine is warm. When it's running, everything operates normally, no noises, everything works.

I took the car to AutoZone and had the battery and charging system tested. Both were fine. I had the guy pull the codes and I got two, PO107 and PO102. The first is for the MAP sensor, and the second is for the MAF sensor.

I've read that damaged or unhooked vacuum lines leading to the turbo or intercooler can cause the computer to show these codes, however when I looked I didn't see any hoses out of place. But at the same time, I just got the car and am not very familiar with the engine layout (anybody got an easy diagram I can look at?) I've also read that a person who had the same problem as I do ended up being the idle air control valve, does that sound like a safe bet? Could it be the fuel pressure regulator? Fuel pump? Fuel pump relay? A combination of these?

 

I would start with the Map sensor in the intake manifold.
Some of the cars share the same sensor with one on the firewall as well or in the intercooler. If you have another one that is the same swap the sensors and see if the code changes.
But I have also see the idle motors go bad.
I have also see the sensor in the induction hose just before the turbo do the same thing.(And threw the same codes you have.)

 

Thanks for your advice tech. The problem ended up being the idle air control valve, I just cleaned it up and the car's running normal now.

 

glad all is good now.

 

I'm getting almost the exact same problem with my 2001 S40 that I just picked up (1.9T). Throws P0107 on my portable OBDII reader, being indicative of the MAP. Sometimes runs fine (so long as you keep the throttle below half), and sometimes runs rough. Today cleaned out the idle motor with brake cleaner as well as the MAP (I think) that's on the intercooler. Cleaned and regapped the plugs (OEM) to 0.75mm, noticed that I have a new MAF and airfilter. Hooked up this plumbing rig I made (for my now burnt 300hp 93 urS4) that I can hook up to my air compressor to listen for air leaks. Seems to hold some pressure, there is a very slow leak but it's not likely the problem. I couldn't find the MAP that's supposed to be somewhere on the firewall. Mitchel On Demand was of no help either. Oddly enough now I'm also getting P0302 which indicates a miss on cyl #2 and it sometimes barely running confirms that, but I may have a bad connection for that one - will revisit it tomorrow. Does anyone have any pics of the various sensors and their locations? It would be greatly appreciated.

 

If you have the one on the firewall it is on the drivers side of the bracket that the O2 sensor plugs are on.

 

Thanks Tech. I found another one on my intake manifold hiding under the fuel rail. I swapped it and cleared theerror codes. Upon testing it again I was getting another set relating to turbo pressure and other ones that kept changing. Swapping it back returns same P0107. The interesting thing is that cyl 2 kept missing even after swapping plugs, coils, and wires (one off my DSM). It was easy to see by hooking up one of those lights the connects inline between the plug and wire. It seems that the more it warms up, the worse it runs. Took it for a 45 min drive today and towards the end it was throwing P0301-P0304 indicating a miss on all cyls. Barely accelerates and maintains hwy speed. Went searching at the scrap yard for another MAP but couldn't find any as there was no S40's there and I couldn't find anything on any 850/S70 that were there. They'll have another S40 coming next week but I'm not sure I'll be able to make it to work every day until then. Anyone have any spares I can buy or know of a cheap place? It's this one listed here as "manifold pressure sensor": http://www.swedishautoparts.com/S40/...ted-parts.html oddly enough it looks exactly like the altitude sensor but costs half as much. I'm not sure I'm on the right track but any help/insight would be much appreciated.

 

Pardon my spelling errors and etc. but I'm writing on a tiny PDA screen.

 

I would also do a compression test to make sure compression is good on all the cylinders.
Also maybe the injectors are acting up.

Also one more thing to try when it does not idle right try tapping the valve in the induction hose just before the turbo and see if it will idle right.

 

Compression test might not be a bad idea but sometimes it accelerates fine so everything points to a sensor gremlin. Tapping the check valve by the intake on the turbo didn't do anything, either did unplugging it actually either (same error codes P0107-MAP lowvoltage and P0302-cyl 2 misfire). What's the check valve for anyways and what sensor is connected to it? Almost seems that the previous owner tried working out the problem by replacing the MAF, airfilter, plugs, WD-40 some connections, and then gave up. Found that the manifold pressure sensor is shared accross some models. Makes sense as it's essentially the 5-cyl block with one cyl chopped off. Anyone have any parts cars with one kicking around? http://www.swedishautoparts.com/shop...1=Start+Search