I am having the worst month with dealing with my 2001 Volvo S40.

The Check Engine light came on after the car started hesitating when trying to accelerate. I take it to my mechanic, and it turns out I get codes to replace the oxygen sensors, catalytic converter and mass air flow.

Almost 2K later, I get another code for a map sensor. Get that changed, and now it reads that there are no codes and everything looks clear. No more check engine light. Well, I bring the car home, and the check engine light comes back home when I restart the car later. Go back, they clear the light, and (once again), it comes back when I start the car.

I have 115K on the car. I really don't know if I should stop putting money into this. I am due for inspection, so I don't know what to do!! Help!!!

 

I feel your pain. I wish you had posted before you sunk 2k. I had the same exact problem and all I did was change the spark plugs (use only Volvo or NGK-Iridium- for some resone these Volvos do not like any other kind). You can check my question earlier. I also had a P0128- t-stat coolant temp too low, etc. I changed the t-stat (thank god I did not have to change the sensor) and all my codes went away. Also make sure you use only premium gas (again there are many things that can throw the O2 sensor-catalitic convertor-mass air flow, etc, namely bad fuel, bad spark plugs, bad coils, and the O2 sensor itself (bet it was the front one).

 

Thanks for the reply.

I think I'm going to try the spark plugroute. I changed them two years ago, but maybe that's all it needs.

I learned the hard way last time about using Volvo brand spark plugs. Last time, I used non volvo spark plugs, and had to get raped, I mean, serviced at the dealership.

I will give an update next week after I order the spark plugs.

 

Good thing I changed the spark plugs. I was having major problems when I tried accelerating. Changing the spark plugs really helped the problem. The check engine light is still on, though. Do you have to clear the code for spark plugs? I might try to run to AutoZone this weekend.

 

Well, just got back from AutoZone, and everything I just replaced (O2 sensor, map sensor, mass air flow) are still coming back up as codes. I've already had the codes cleared, drive home and the check engine light keeps coming up. They changed the mass air flow already. I think the O2 is a "new" code. All of these parts are under warranty, I just don't understand why the cleared codes just can't stay cleared [:@]

I'm sure my mechanic is sick of seeing me. I don't know what else to do! Anyone have any other recommendations?

 

One night when I was driving home in my Volvo the check engine light starts flashing, and the idle changes. I run the codes the next day at Autozone, with it coming up with mulitiple codes. I was about to change my Volvo oxygen sensor and the cats, then the mechanic told me to replace first my spark plugs and see if it will fix my problem... The next day I started the car and all the codes went away... I don't really know what happens but I'm glad it happened because because it saved me some bucks... Try also to check all the fuses in the underhood fuse box. My mechanic also to me that sometimes wiring problems cause multiple codes. Good luck!!!

 

Just got back from the mechanic. There are no vacuum leaks...I've changed the spark plugs, the car runs fine, but for the 4th time, they clear the codes, the check engine light goes off. Except when I turn the car off and then back on, the check engine light comes back on. I really don't want to go to the dealer. Could this be a computer problem? I got the computer upgrade a couple of years ago.

 

Still getting the map sensor code?

You know there is 2 Map sensor right?

 

Hi Tech,

No, I did not know there were two. The one he changed was visible next to the engine. Where is the other one

 

The other one should me mounted in the top of the intake manifold.

 

Is this something I should have the dealer do? Or is it something that I can change?

So far, I have new spark plugs, 2 O2 sensors, new air filter, new mass air flow sesnsor, and new MAP sensor.

 

You should be able to do it without any problems.

Do you know what it looks like?

If so look for it in the top of the intake. Only 1 screw holds it on.

 

Is this it?

http://69.0.158.19/live/C7044132779BOS.JPG

I will take a look tommorow and see if I can see it. I can't believe there are two map sensors, and the mechanic doesn't know. [:@] Since the car is running good, he basically told me that it's probably a computer problem, since the check engine light comes back on after I turn off the car. This has been going on since the first week of May. He told me to get it reset at the dealer, but I don't want to pay to have them reset it like he does, turn off the light, and then have it come back.

 

No thats not it. It should look exactly like the other one.
If you can get ahold of the old one he replaced get it and install the new one on the intake and the old one where you took the new one from.

I know there is 2 because we went through the same thing on a car at work.

 

i have the exact same problem I replaced the o2 sensors air idle control map and maf and nothing so i took all my cats off had someone clear the inside out and still nothing. Now i have an added code cam shaft position sensor -1 its driving me crazy. [][][]

 

Ok. I took a look in the engine and found the Map sensor on top of the intake, except it doesn't look like the part that the mechanic showed me that he changed.

Tech, where is the other map sensor?Now, I'm wondering if the changed the wrong part.

 

The other one is under the black cover at the firewall.
It is mounted on the same brakcet that the O2 sensor plugs are on.

 

Thanks so much, tech!

I'm going to find out which one he changed. I'm guessing he changed the top one, b/c he told me that it was a really quick install,

Did you recommend any brand? Is OEQ ok?

 

We always use OEM not sure about any others.

 

Before my present 2002 Volvo S80 (not turbo), I had a Mercury Cougar for 17 years, a great car but for at least last 20k miles its engine light was on and I drove it with not even a minor problem. I changed Oil each 6000 mile. Now I have this Volvo, which drives great but has same Engine light one. I have tried every tricks on the book and on the web to no avail. I'm going to keep driving and keep changing oil when I feel its the right time. Auto dealers and mechanic of today, are no better than doctors, bankers and lawyers. A bunch of vultures you better stay away as far as you can. You go to change a spark plug will cost you an arm & leg and when you drive home, you'll notice your car has new problems that never you had. Drive the car and keep vultures off your hear.