Hi,

I'm new here and stumbled upon this site while researching some issues with my 2000 S40. We just bought the car (very) used yesterday for pretty cheap from a private seller with 170K on the odo. I had this exact year/model years ago, and really liked the car back then, so we decided to get another one to use as an extra car for anyone in the family to use if needed.

When I test drove the car, everything seemed fine (mostly). I noticed that I couldn't feel any boost from the turbo, but didn't think a whole lot of it. Now it seems like it may be problematic.

Today, I went to go take the car for the emissions test so I could get license plates, and on the way there the check engine light came on. I brought the car home, disconnected the battery for about 15 min. to see if it would reset whatever sensors might be complaining. No dice, but on my way out to Autozone to get codes pulled the light went out for awhile, only to return a few minutes later.

Autozone pulled codes P0101 and P0234. Obviously this has something to do with the turbo function (or lack thereof). Should I expect a big repair bill for this, or is this something I might be able to fix myself for relatively cheap? Is this a common issue?


Thanks!

 

Hi and welcome to the forum.

I have not searched for the code, hopefully someone will help you out soon. Have you checked all of the vacuum lines?

Also, resetting the computer with a reader or by disconnecting the battery will usually cause a SYSTEM NOT READY and you will fail inspection due to the not ready situation.

 

P0101 is MAF sensor and P0234 is overboost. My guess is one of the two MAP sensors has failed causing the ECM to "think" it's already making boost. This would cause the ECM to try to open the wastegate to lower boost levels which would mean no boost in reality. Also, the MAF sets a code because it's not seeing the flow it should be seeing at the reported boost level. Just a guess.

Anyone remember which MAP sensor is for boost? The one on the intercooler or the one on the intake?

You could try switching the 2 MAP sensors. Rumor says they are identical. Don't know for sure.

 

Looks like they are. Just checked mine and both have the same part number.

 

Thanks guys. I'll look into the MAP sensors as soon as I can.
There is definitely no boost, but I don't seem to have the issue like others have where the car limps along otherwise.

I recall being able to clearly hear when the turbo spooled up with my old S40, and this car has absolutely none of that. The previous owner said that he had recently had a new timing belt installed. Is is possible that this work may have caused this?

 

Easy enough to check. Remove the timing belt cover and rotate the engine until the timing marks line up with cam marks and crank mark.

 

The timing belt wouldn't cause that. It's usually a bad MAP sensor but can be a bad MAF or a vacuum leak.

 

Thanks, guys. What I was looking for was whether or not the work to swap out the timing belt could have affected these sensors or hoses, but it doesn't sound like it could.

I'm reading some posts that suggest that the 2000 model may only have one MAP sensor, and that the 2nd sensor was introduced on the 2001 model. Is that the deal? Parts seem really reasonable for both a MAP and MAP sensor and I also need a fastener for the air box - one of them seems to be missing, and I'm sure they'll fail E-tests for something like that. Seems like the cheaper option to just replace all this stuff myself than pay for a shop to check to see if they need to be replaced.

Oh yeah by the way, I drove it to work today and did detect a tiny bit of boost once while accelerating.

 

Okay, so I dropped in a new MAP sensor this afternoon. Do I need to get the check engine light reset, or should it go away on its own? I'm trying to figure out if I still need a new MAF sensor as well.

 

Stop by your local Autozone or similar and have it reset. Then drive it to see if the CEL returns.

I've read some threads about the 2000 model only having one MAP. One way to check for certain. Look at the charge air cooler and see if there is a MAP sensor mounted to the center top air connection. Here is a pic someone else posted:

 

Here is the exploded view of the charge cooler (aka intercooler). Number 3 is the MAP sensor:

 

I checked and did not see a 2nd MAP sensor in that location. I'll triple check though when it's daylight again. I got codes pulled again and it's still throwing P0101, P0234 and now P0172. I've ordered a MAF sensor, so hopefully that yields some headway. It does seem to get slightly better fuel economy since the MAP sensor change, so I don't think it was fruitless.

 

Please let us know when it's fixed. It helps when a solution is found so others searching can benefit.

 

Ugh...I went to start it up yesterday, and now it's sputtering and won't stay running. The new MAF sensor is supposed to arrive on Monday, but it seems like now it's going to need more work. It almost seems like a bad coil, but I can't be sure, and I can't very well get it to Autozone again to get codes pulled again.

I'm starting to think I made a big mistake buying this thing.

 

MAF sensor arrived today, and the replacement went without a hitch. However, the new issue persists and the car is running poorly.

I don't know if I'm crazy or hearing things now, but it sounds like I can hear the turbo now when idle, and much louder than I ever remember being able to hear it before. And when I press the gas (on the rare occasion that it doesn't stall out) it sounds like its trying to boost, but the car isn't accelerating.

 

I think the poor running condition may have been caused by some bad fuel. On a whim, I just put in my garage gas (was intended for my dirtbike and ATVs), and the car runs 200% better. There's still some stalling here and there that didn't exist prior to all this, but I think that will go away as soon as I fill the car up with some good gas.

Now, off to the auto parts store to get a scan tool. The 15 mile trip (one way) just to get codes scanned isn't working for me.

 

I picked up an OBD-II tool. At first it was showing even more codes than I knew about. Along with the P0101, P0234 it was now showing P0170 (not 0172 like before), and P0304. I wouldn't doubt that these were thrown during the rough running and other fun adventures this car has had.

I cleared everything and filled the car up with known good gas. It's now running smooth mostly, and I can definitely hear the turbo. Still, I feel no boost even though it's spinning up and down with the engine. Not sure what to make of that. Hopefully some clean codes will show up and point me in the right direction.

 

P0101, P0234 and P0172 are baaaaack. The CEL isn't on again...yet.

 

I had a similar problem. It ended up being that the hose near the map sensor that goes to the idle air control valve near the throttle body was broken.

The car was very sluggish and ran rough. Came close to stalling a few times.

P0172 came up for that, but I only ran it a day like that before replacing the hose.

Hope that or something as simple is your issue.

 

Tentative victory!

After some tinkering around, I traced the turbo noise down to the hoses that run down by the bottom of the radiator. Lo and behold, the hoses were disconnected right after the bend. I don't know if this hose is supposed to be two pieces like this, as I haven't been able to find a diagram as of yet. But there was a regular hose clamp keeping the two together, and it appears to have been knocked off. The plastic guard underneath the nose of the car is kind of torn up like someone hit a curb or something, and that incident likely knocked these hoses loose.

After mating the hoses back together tight and clearing codes the car drives like I would expect, and so far no new codes! I'm going to drive it to work tomorrow and see how it behaves. Hopefully that took care of things and I can get the E-test done on this thing.