Where is the Turbo Boost Sensor A?

Candonm · Post by **Candonm** » 04 Mar 2009, 23:40

Just got our car back from the dealership and said that we need to replace the turbo boost sensor A? Here's what are car is doing, stalling when we come to a stop, doesn't respond right away when accelerating, and putters and finally kicks in after a couple of seconds. We had the throttle body codes (recall) replaced, but problem remains. We haven't been able to drive it for 2 years because of the problem and still paying it off. We want to buy the part and replace it ourselves but want to make sure we know where it is and if this sounds like the problem. Please help.
Thanks
One more thing is the turbo boost sensor A and map sensor the same thing?

Post by **MadeInJapan** » 05 Mar 2009, 16:15

Welcome to MVS.
I'll try to look that up for you but first I need what model year and trim level S80 you have.

Post by **vegasjetskier** » 05 Mar 2009, 16:40

MadeInJapan wrote:Welcome to MVS.
I'll try to look that up for you but first I need what model year and trim level S80 you have.

Under his login name it says 1999 S80 T6.

Candonm · Post by **Candonm** » 05 Mar 2009, 16:47

Hi there it's a s80 T6 1999
Anything would help at this point we ordered the part this morning just need a little help finding the spot to put it!

Post by **MadeInJapan** » 05 Mar 2009, 18:11

Sorry guys...not used to looking over there- it's a new feature on the site. Let me take a look now and I'll report back.

EDIT: I don't see that terminology being used in VADIS (Turbo Boost Sensor A). Instead, I see two things that control the turbo- the TCV (turbo control valve) and the Boost Pressure Control (BPC) valve. I'm wondering which they are referring to. Did they by chance tell you about where the one that is failing is? I've replaced the TCV to a beefier one (from IPD) on both our S70 and V70...it is on the side of the air filter box and has 3 small vacuum hoses running to it. The other one (BPC), from looking at VADIS is the same as the wastegate on earlier models...in other words, it's at the end of the arm that actually closes and opens the turbo's flow-through opening. The only one that's a true electrical connector that can be probed for a problem code, etc. is the TCV. It has a few different names (IE: Wastegate pressure regulartor): http://www.eeuroparts.com/Main/PartDeta ... id=9155936 This part, if bad can also be replaced by the heavy duty one sold by http://www.ipdusa.com and if I had to replace mine, I would go their route for a few more bucks. That said, often the lines to the valve get bad or disconnected, or put on wrong by a mechanic working on the turbo or around that area- check all of this carefully. Also, check the electrical plug to the valve to make sure it's clean and not corroded (all could be the source of your bad sensor code). The TCV is color codes...the red line goes to the bottom of your turbo, the yellow line goes to your wastegate and the blue line goes to the underside of the air intake (accordion) hose just past the MAF sensor. I hope what I have posted is helpful to you. Post back to let us know if you were able to problem solve this further.
-MIJ

One more note- because your car has twin turbo's, I'm suspecting that there are actually 2 TCV's on your car...and that the "A" designation is for the turbo that is attached to cylinders 1-3 while there is a probably a "B" designated TCV connected to the turbo that services cylinders 4-6. You can call IPD and talk to Lucky or Scott to confirm. They are great guys who will help you problem solve this issue. Tell them that MadeInJapan sent you their way.

Post by **vegasjetskier** » 06 Mar 2009, 08:31

Candonm wrote:We want to buy the part and replace it ourselves but want to make sure we know where it is and if this sounds like the problem. Please help.
Thanks
One more thing is the turbo boost sensor A and map sensor the same thing?

According to the drawing in VADIS, no they are not the same thing. The boost sensor is located in the large air pipe that goes between the charge air cooler (intercooler) and the Electronic Throttle Module (which is mounted to the bottom of the intake manifold). You should be able to see it behind the radiator and in front of the engine. I would post the drawing here, but I can't figure out how to copy it (apparently there is some security on the VADIS software).

I took a couple pics of my car. Open the hood and look down into this space:

: SensorLocations1.jpg (114.95 KiB) Viewed 24919 times

You will see the sensors here:

: SensorLocations.jpg (99.24 KiB) Viewed 24926 times

The one on the left is the air temperature sensor and the one on the right is the boost pressure sensor.

Post by **MadeInJapan** » 06 Mar 2009, 16:17

Hey Vegas,
Thanks for your input.
The way to copy from VADIS is to use a program like Win2PDF and just print to file in that program...a window comes up asking you where you want to save it...then you have it to share with others. Just do a google. My version of Win2PDF is devoid of the extra page that says it's a trial version- I think that for the newer versions you have to buy the code for that to disappear.

Post by **vegasjetskier** » 08 Mar 2009, 09:22

MadeInJapan wrote:Hey Vegas,
Thanks for your input.
The way to copy from VADIS is to use a program like Win2PDF and just print to file in that program...a window comes up asking you where you want to save it...then you have it to share with others. Just do a google. My version of Win2PDF is devoid of the extra page that says it's a trial version- I think that for the newer versions you have to buy the code for that to disappear.

Hi, MIJ. I uploaded the program, but when I try to print a VADIS page it just shows me my default printer (a real printer) as the only option. Win2PDF isn't there to choose.

Post by **MadeInJapan** » 08 Mar 2009, 13:53

You'll have to enable it through Start/Printers and Faxes.
I never have been able to just print a page- like the parts diagram. I'm better off just doing "print screen" and then using a graphics program, but printing a topic works very well.