01 s60 2.4t Miles: 127K Fuel: always premium Oil: Always Synthetic Ultra

Hello and thank you in advance for the help.

A while back I had an incident while driving on the highway where I seemingly lost power at the gas pedal after going over a pothole. When I hit the pedal the RPM would move accordingly but I wouldn't get hardly any power. I pulled over and parked, turned off the car and failed to find anything obviously wrong. I turned the car back on and it performed fine for months and I wrote it off as a fluke. A couple of weeks ago it happened again and today it happened repeatedly and a check engine light came on with a "Service engine" message on the read out. I went to a service station to check the code and pulled P2126, p0234, p0496, and p0497. One is for "throttle position sensor switch E" and the others are variations on turbo overboost and purge valve errors.

I am not sure if I have multiple issues or if one caused all the others. I haven't seen the symptoms described this way anywhere.

 

P0234 - Turbo over boost, seemed to be most inline with the trouble you posted. Other symptoms would include overheating, knocking and misfire.

The most common cause is the wastegate not opening properly.

That symptoms started post pothole I would look for loose vacuum hoses near the wastegate, bent or loose wastegate actuator rod and overall wastegate mechanical functionality.

 

Thanks, I'll have a look at the wastegate and report any weirdness.

 

Alright, I pulled off the heat shield on my turbo assembly. It was covered in a rusty patina but still solid. the cotter pin was still solid and on and the rod still moves freely with several pounds of force acting on it. I drove with the windows down to listen carefully for turbo noise and it seems to be working properly.

I took my car to Autozone since I was informed by my indie service guy that they have a better diagnostic tool than he has. Their machine pulled the same codes and suggested the evap emissions purge solenoid. I'm willing to bite the bullet on a forty dollar purchase and a little time to install myself if anybody here thinks that remotely sounds correct. Otherwise I'm going to have to go to a mechanic to diagnose the problem which I can't really afford due to being between work and dealing with my apartment jacking up its prices. I appreciate any help I get, thanks.

 

That is the most likely fix for p0496/7 but not the others... when you had people check the codes did they clear them and came up again? If so, at what intervals? Is the no power issue still present?

I'll be at work tomorrow and try to do a little digging in the database for this issue. No promises if I'm swamped.

 

I appreciate the help. For some reason he did not clear the codes. The power issue was still present. I also noticed that my warm idle was around 750rpm. I believe that is a change. Could this be a bad air hose or line?

 

OK. A little update. I was alerted to the fact that I may need to use my car for a business trip next week so I bit the bullet and took "Tough Dependable Sixty" to a higher end import specialist and got their costly opinion. They reread the codes (Which weren't cleared by the Autozone guy.) and they pulled apart a few things to take a better look under the hood. They have determined that some of my air lines have been damaged and recommend replacing the whole set as well as my boost control valve and purge valve for around 65 a piece. They also list "Vacu repair parts" for $345 dollars plus 250 in labor all together. I'm going to get a second opinion from another shop since right after I started the process at the shop I was informed my vehicle wasn't needed so now I have time. Does all that fall in line with what I've been experiencing?

 

Sorry, been a rough 2 days at work...

P2126 is the major issue and probably causing p0234. That means replacing the accelerator pedal position sensor. Rock auto has them for $110-130. I couldn't find info on how to test the unit to ensure it was bad but didn't dig very far.

The most you would gain from replacing the EVAP purge solenoid is better fuel economy and over the long term potential damage to the catalytic converter.

I ask my buddy at work about this and he agreed. He's more experienced than me with engines and turbos, however he has zero experience with Volvo.

 

I sort of went in that direction until I thought about the rpm still rising with presses on the pedal. Could that still happen with that being the problem? I know I could be wrong but that's just what common sense told me.

 

There are 3 sensors total in the unit... 2 work together to check and balance each other for pedal position. The code is actually those 2 sensors being "out of range" or saying the 2 sensed positions are too different to be a true reading. When it reads the error it defaults to sensor 2 as being "true."

Other than them using change in voltage to determine pedal position, I don't know enough about how they work to be much help. You could google them and their functionality, possibly find a decent YouTube showing how to test them.

 

Okay, so I've talked to my local dealership and the high end indie and I believe my power issue is a condition I wasn't making the connection to until now. Limp mode. I've heard of it before, but my mind went to the turbo and never thought about that. So I will be taking my car to the dealership to be serviced with official parts for about the same price as the high end indie. I'll be getting the vacuum lines, turbo control valve, and evap valve replaced. I'll report back afterward.

 

Okay, I've had the new parts in for about a week and I have experienced no issues but also sizable performance improvements. It's driving like when I first got it again. I guess I didn't notice the change since it was so gradual. Here's a picture of one of the lines beneath the turbo from what the technician tells me.