How does one test the tps voltage? Warm the car up, then...

 

Don't use the voltage method to adjust the TPS. Use the resistance method. Try a search for "TPS adjustment".

 

You don't need to warm it up to test it.

That's just to adjust it. If you're adjusting it, go to the archives there is a HUGE thread about it in there, lots of reading.

Otherwise, just unplug it... if you have an S4 you'll only have 1 sensor, if you have an S5 you'll have two. There will be three wires per sensor.

Set your OHM Meter (Multimeter) to resistance (ohms) and to measure in K-Ohms (Thousands, Kilo).

On an S5 you will have a 3x2 row of pins... the middle row of 2 pins doesn't matter, to measure one sensor connect the leads to the two points that are in line with each other on one side, push the TPS in and see which one makes the resistance go up... check it for tolerances, repeat for the other side/other sensor.

On an S4 it's a lot easier, I forget which pins of the three it is, but just pick two and if the resistance doesn't look right try switching to another pin. ;P

You should have a FSM anyway, it'll tell you which pins are what.

--Gary

 

I don't get to disagree with you too often, Aaron, so I'll give it a go...

There's a little rule that most electricians use to troubleshoot circuits, and that's to check as much of the complete circuit as possible for your first step in troubleshooting. Then, if something's not quite right, the circuit gets broken down into segments, or components...

Checking the TPS for resistance is not a bad thing, but if the wiring is screwed (especially at the connector, which loves to corrode), you'll be lulled into a false sense of security thinking that the entire TPS circuit is good.

This is why, as some of you may have noticed, I instruct guys to do some troubleshooting perhaps a little differently than most would. I've been doing this kind of stuff for a couple of decades now. I'm not saying I'm always right, lol, but I do have much more electrical troubleshooting experience "under my belt" than the average Joe. I've lived and learned, so to speak...And, I'm using this experience to save you guys some trouble and mistakes (that I've already made numerous times, lol)...

Getting and adjusting that 1 volt at the ECU verifies the entire TPS circuit, whereas checking just the TPS for resistance verifies a small portion of the circuit, while leaving the rest of it an "unknown". If the voltage is right at the ECU, the resistance is right at the TPS, period...

 

I'll stick in my .02 cents. As Wayne stated the 1 volt=correct resistance, but doesn't indicate the TPS is set correctly, only the starting point is correct. Experience dictates final adjustments must be made.
Here we go again!!!

 

Do you not check at the ecu then adjust tps to get correct reading at ecu?

 

In the Fuel Section of the FSM there is a section called Control Unit. It shows the output/inputs to/at the ECU while the engine is runnning. Note carefully that at pin 2G, the put of the tps to the ECU is APPROX 1VOLT. Need we say anymore??? NO. Does that approx 1volt mean the tps is perfect? NO. There is another section that deals with checking out the tps itself.

 

Dare we define "approximately", lol?

Last week I removed the TPS assy from my throttle body to redo some wiring (the wiring was oxidized a good 1"+ from the connector wire terminations), and noticed that the mounting holes & bolts for the TPS were not exactly what you would call close tolerance (if the bolts are loosened a bit, you'll see that you can rotate the TPS more than a little, which will throw the adjusted position out). Needless to say, when I reinstalled the TPS I knew it was going to need readjusting. After reinstalling & warming the car up, she was pushing .8v (had her set at a perfect 1v before removal). What surprised me was that the car ran like crap at that .8v...She didn't get back to "normal" until I tweaked her into the .95v range. Moral of the story- at least on my car, just .2v was enough to make a big difference. So, I ask again, what is "approximately"?

And yes, Greg- leave a meter on that ECU pin, get her hot, and adjust TPS while idling and watching the meter. Temperatures affect the readings a lot more than I gave it credit for, and I'm not talking about the thermowax having anything to do with it, so make sure she's very warmed up...

 

thanks I'll do it