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With the TPS temporarily installed, we now need to wire it up. The wiring we do in this step will not need to be be undone and will be permanent, so take your time.
Set the TB so the wiring harness side is opposite to you. Now look at the side with the 5 pins. The second pin closest to you is the one we will be soldering the TPS wire onto. The pin with the wire going into it is the one I'm talking about in the photo below:
If you look on both sides of the contacts, you will see two metal ridges. The one near the top of this photo is solid. The one near the bottom is hollow. The contact you want is the 2nd closest to the hollow ridge.
![299261]()
We need to separate ONLY this contact. Not all 5, just this one. This is a huge pain in the ass, but its possible. Again, it is spot welded, so you cant desolder it. Enough prying and you’ll get it. I wound up finding a tiny chisel and hammering it between the two contacts. This was a stupid idea. It worked, but I could have badly damaged something so I’m not going to recommend it. The below photo is taken from the opposite side of the TB compared to the last photo. Dont let it confuse you because the broken contact in this photo is further away.
![299262]()
Some kits come with the TPS wire pre-stripped. If yours didn’t, then strip the insulation off the end. DO NOT cut the wire. If you do cut it, you can still finish the job, but youll have a harder time tuning the voltage. Don’t cut it. Just strip the insulation off the end.
Pry the two contacts apart, make sure they are clean, (You don’t have to sand down the spot welds) and tin both of them. At the same time, tin the TPS wire and slip some heat shrink tubing over it. Now clamp the TPS wire between the two contacts and solder them together. Make sure this is a good joint. You wont be happy if it breaks. I put heat shrink tubing over all 5 contacts just to prevent them from shorting one another. The correct way to do this would be to re-pot them.
You’re about done, now. Time to tune the voltage. Here is how the tuning process works.
Below is an Ms paint drawing. This is the top view of the magnet, looking down on the shaft. The red is the magnet, black is the shaft. You may remember that the magnet had some freeplay around the shaft. You can rotate the magnet a few millimeters in either direction. In one direction, your voltage will decrease. In the other, it will increase. This is how you set the voltage. You have to remove the TPS, unbolt the magnet, rotate it, bolt it back down, put the TPS back on, and test it. Repeat until you get it right. This is the worst part of the entire process. If you have a way to apply voltage to the TB, that is the way to go. I was unable to find a pinout and did not want to fry anything, so I didn’t do this. I’ll explain what I did in a minute. I will also explain how to read the voltage.
MS paint drawing:
![299263]()
I spent 2 days trying to figure out what the correct voltage was. This is not documented anywhere online or in any Lamborghini service manuals. @Glumpy3 measured his OEM TB voltages and got 1.36V and 1.41V. Keep in mind, though, his TBs were going bad. I started working within this range and found that my car worked perfectly, just like stock, at 1.399V. In reality the car has a range It can function within. I don’t know what that range is, but if its anything like the Volvo TB units (which is what is in our car), its probably between 1.38V and 1.42V. My 1.399V worked, so that is what I’m recommending. Again, sample size of 1. I have to recommend you also test voltages in this range, but my 1.399V worked. I want to repeat myself once more to make this absolutely clear: the voltage that worked for me, may not work for you. The volvo guys sometimes come up with different functional voltages. I have to recommend you test different ones instead of just setting to 1.399V and being done.
I also know what incorrect voltage does, because that is how I almost crashed my car. Initially I set the voltage to 1.5V on both TBs. This resulted in the car idling at a very low RPM. I was driving it and it felt like it had 200 horsepower. After a while I started getting a “Low Battery” light. I thought it was my battery. It was actually because the engine was struggling to keep going due to the idle RPM being so low. The engine was cutting out, but I didn’t know it at the time. When I was getting close to my house the RPMs dropped all the way down to 450 and the car stalled. Without power brakes or power steering, this heavy car is hard to steer. I missed my fence by a few inches and even standing on the brakes I wound up a few millimeters away from driving straight into the side of my house. I was lucky and this part is important. If I was on the highway I surely would have hit another car.
Another thing to note. On my car, in order to get the correct voltage, I had to cut the shaft at an angle so I could rotate the magnet more. Do not do this until you test the voltage on your car. I am a sample size of 1. Once you cut an angle into the shaft, you cant go back.
This shows how you have to cut the magnet. Again, looking down from above:
![299264]()
Now onto how you can test the voltage. If you have a way to apply 12v to the TB and you can find a pinout, great! I didn’t. So here is how I did it:
You first have to understand how the car tests the TB. When you put the car into Aux2, it runs a bunch of tests. If you’re quiet you can hear them happening. One of these tests is to make sure the TB is responding. When you turn the key to Aux2, the car will briefly open the TB to 100%, then close it again. Its over by the time the “OK” appears on screen. The car is stupid and does not care what the voltage is, it just wants to make sure it responds. This makes measuring the voltage difficult, because you cant be inside and outside the car the same time. If you want to stay married, you also cant ask your wife to sit in the garage for 6 hours while you do this. I came up with a setup to do it on your own.
First, the contacts you have to probe are the two outer contacts on the TPS side. The contacts with the heat shrink coming off of them are the ones I’m talking about:
![299265]()
I did not have alligator clips which would fit, so I made my own ghetto probes out of wire lengths. I used slightly shrunk heat-shrink to easily slip them on/off the contacts:
![299266]()
I also did not want to keep screwing the TPS on and off, so I got a woodworking clamp. I clamped the TPS down so the contacts were touching one another. That’s all that matters.
![299267]()
Now you’re setup to measure the voltage. Plug the TB into the car, set your meter to DC volts, get it hooked up to the probes and set it on your exhaust “shelf”. I propped a phone above the multimeter, and set it to record a video.
![299268]()
With the phone recording, get in the car, turn the car to Aux2, wait for “OK’ to display, shut it off, and check your recording. You will see the voltage go from 0v -> Xv -> 0v. The highest number is what you care about. That is the number you want to get in the right range, or what I’ll be calling 1.399v.
Your next task is to figure out which direction increases the voltage and which direction decreases the voltage. Undo your entire rig, remove the TPS, unbolt the magnet, turn it all the way to right, and retest. Repeat, but turn the magnet all the way to the left. Now you know the range you’re capable of getting without cutting the shaft, and you now know which direction increases/decreases the voltage.
From here on, this is what you will be doing until you dial it in to 1.399v. Repeat until you get there. Good luck.
Once you finally have the voltage right, all you have to do is reassemble the unit.
Tin the 3 contacts on the TPS and the TB. Solder them together. Torque the bolt down and Loctite it. I didn’t remove it, I just dripped Loctite over it and let it seep into the threads. Screw down the TB. Tape the TPS wire down so it doesn’t get inched, and seal the metal panel back to the TB. I chose to put adhesive heat shield under the TB because I didn’t want the solder joints getting too hot. I also put heat shrink around all the contacts. Again, the right way to do this would be to repot it.
![299269]()
You’re done! Wasn’t that easy?
I’ve been writing for hours and have to stop. Here are some supplemental resources:
Has anyone here done a TPS swap or installed a XeMODeX...
Volvo s60 P/N 8644345 2001 non-turbo ETM pictures
Set the TB so the wiring harness side is opposite to you. Now look at the side with the 5 pins. The second pin closest to you is the one we will be soldering the TPS wire onto. The pin with the wire going into it is the one I'm talking about in the photo below:
If you look on both sides of the contacts, you will see two metal ridges. The one near the top of this photo is solid. The one near the bottom is hollow. The contact you want is the 2nd closest to the hollow ridge.
We need to separate ONLY this contact. Not all 5, just this one. This is a huge pain in the ass, but its possible. Again, it is spot welded, so you cant desolder it. Enough prying and you’ll get it. I wound up finding a tiny chisel and hammering it between the two contacts. This was a stupid idea. It worked, but I could have badly damaged something so I’m not going to recommend it. The below photo is taken from the opposite side of the TB compared to the last photo. Dont let it confuse you because the broken contact in this photo is further away.
Pry the two contacts apart, make sure they are clean, (You don’t have to sand down the spot welds) and tin both of them. At the same time, tin the TPS wire and slip some heat shrink tubing over it. Now clamp the TPS wire between the two contacts and solder them together. Make sure this is a good joint. You wont be happy if it breaks. I put heat shrink tubing over all 5 contacts just to prevent them from shorting one another. The correct way to do this would be to re-pot them.
You’re about done, now. Time to tune the voltage. Here is how the tuning process works.
Below is an Ms paint drawing. This is the top view of the magnet, looking down on the shaft. The red is the magnet, black is the shaft. You may remember that the magnet had some freeplay around the shaft. You can rotate the magnet a few millimeters in either direction. In one direction, your voltage will decrease. In the other, it will increase. This is how you set the voltage. You have to remove the TPS, unbolt the magnet, rotate it, bolt it back down, put the TPS back on, and test it. Repeat until you get it right. This is the worst part of the entire process. If you have a way to apply voltage to the TB, that is the way to go. I was unable to find a pinout and did not want to fry anything, so I didn’t do this. I’ll explain what I did in a minute. I will also explain how to read the voltage.
MS paint drawing:
I spent 2 days trying to figure out what the correct voltage was. This is not documented anywhere online or in any Lamborghini service manuals. @Glumpy3 measured his OEM TB voltages and got 1.36V and 1.41V. Keep in mind, though, his TBs were going bad. I started working within this range and found that my car worked perfectly, just like stock, at 1.399V. In reality the car has a range It can function within. I don’t know what that range is, but if its anything like the Volvo TB units (which is what is in our car), its probably between 1.38V and 1.42V. My 1.399V worked, so that is what I’m recommending. Again, sample size of 1. I have to recommend you also test voltages in this range, but my 1.399V worked. I want to repeat myself once more to make this absolutely clear: the voltage that worked for me, may not work for you. The volvo guys sometimes come up with different functional voltages. I have to recommend you test different ones instead of just setting to 1.399V and being done.
I also know what incorrect voltage does, because that is how I almost crashed my car. Initially I set the voltage to 1.5V on both TBs. This resulted in the car idling at a very low RPM. I was driving it and it felt like it had 200 horsepower. After a while I started getting a “Low Battery” light. I thought it was my battery. It was actually because the engine was struggling to keep going due to the idle RPM being so low. The engine was cutting out, but I didn’t know it at the time. When I was getting close to my house the RPMs dropped all the way down to 450 and the car stalled. Without power brakes or power steering, this heavy car is hard to steer. I missed my fence by a few inches and even standing on the brakes I wound up a few millimeters away from driving straight into the side of my house. I was lucky and this part is important. If I was on the highway I surely would have hit another car.
Another thing to note. On my car, in order to get the correct voltage, I had to cut the shaft at an angle so I could rotate the magnet more. Do not do this until you test the voltage on your car. I am a sample size of 1. Once you cut an angle into the shaft, you cant go back.
This shows how you have to cut the magnet. Again, looking down from above:
Now onto how you can test the voltage. If you have a way to apply 12v to the TB and you can find a pinout, great! I didn’t. So here is how I did it:
You first have to understand how the car tests the TB. When you put the car into Aux2, it runs a bunch of tests. If you’re quiet you can hear them happening. One of these tests is to make sure the TB is responding. When you turn the key to Aux2, the car will briefly open the TB to 100%, then close it again. Its over by the time the “OK” appears on screen. The car is stupid and does not care what the voltage is, it just wants to make sure it responds. This makes measuring the voltage difficult, because you cant be inside and outside the car the same time. If you want to stay married, you also cant ask your wife to sit in the garage for 6 hours while you do this. I came up with a setup to do it on your own.
First, the contacts you have to probe are the two outer contacts on the TPS side. The contacts with the heat shrink coming off of them are the ones I’m talking about:
I did not have alligator clips which would fit, so I made my own ghetto probes out of wire lengths. I used slightly shrunk heat-shrink to easily slip them on/off the contacts:
I also did not want to keep screwing the TPS on and off, so I got a woodworking clamp. I clamped the TPS down so the contacts were touching one another. That’s all that matters.
Now you’re setup to measure the voltage. Plug the TB into the car, set your meter to DC volts, get it hooked up to the probes and set it on your exhaust “shelf”. I propped a phone above the multimeter, and set it to record a video.
With the phone recording, get in the car, turn the car to Aux2, wait for “OK’ to display, shut it off, and check your recording. You will see the voltage go from 0v -> Xv -> 0v. The highest number is what you care about. That is the number you want to get in the right range, or what I’ll be calling 1.399v.
Your next task is to figure out which direction increases the voltage and which direction decreases the voltage. Undo your entire rig, remove the TPS, unbolt the magnet, turn it all the way to right, and retest. Repeat, but turn the magnet all the way to the left. Now you know the range you’re capable of getting without cutting the shaft, and you now know which direction increases/decreases the voltage.
From here on, this is what you will be doing until you dial it in to 1.399v. Repeat until you get there. Good luck.
Once you finally have the voltage right, all you have to do is reassemble the unit.
Tin the 3 contacts on the TPS and the TB. Solder them together. Torque the bolt down and Loctite it. I didn’t remove it, I just dripped Loctite over it and let it seep into the threads. Screw down the TB. Tape the TPS wire down so it doesn’t get inched, and seal the metal panel back to the TB. I chose to put adhesive heat shield under the TB because I didn’t want the solder joints getting too hot. I also put heat shrink around all the contacts. Again, the right way to do this would be to repot it.
I’ve been writing for hours and have to stop. Here are some supplemental resources:
Has anyone here done a TPS swap or installed a XeMODeX...
Volvo s60 P/N 8644345 2001 non-turbo ETM pictures
