I'm referring to the TPS troubleshooting site linked by the faq's - http://vbxmaxima.8m.com/tps.html . Well, I borrowed a Multimeter from my Physics teacher today, and was excited that I would finally get to readjust the TPS. Since I don't have a CEL, I figured this would work. Well, I disconnected the far connector, attached the pos. lead to pin 1 in the diagram, grounded the neg. lead, turned my key to on, and got NO READING OF VOLTAGE (it was supposed to be 5 volts). I thought this was odd, and decided to test the ohms put out by pins 2 and 3 at different throttle positions, and got nothing (it's supposed to be between 500 ohms and 4000 ohms at different throttle)...Is there something I'm doing wrong? The multimeter works -- tested on a D battery today. Does this mean my TPS is completely shot? Again, I don't have a CEL. Please help.

Lou

 

bump so that someone will at least read it...

 

I read it before but I just wrote it off as you not doing it correctly. You followed all the directions right? You unplugged the BROWN connector, and checked resistance(ohms) on the sensor itself not the connector right? I had the same problem, but I just tried a different combination of pins and got it to work fine.

 

Why are you playing with your TPS if you don't have a CEL?
Do you have a problem that might be related to the TPS?

 

yes, I'm actually using the pins on the sensor, and I am using the correct sensor (the one with the brown connector). When I turned the key to ON, but did not start it, I got absolutely no reading of voltage. When trying to get the resistance of the other two pins (2 & 3), I had no reading of resistance whatsoever. I'm going to try again today, but I don't think it will be much help.
I'm fooling with my TPS because I have the symptoms of a bad TPS. My engine speed falls below idle when putting the clutch in, and then shoots back up to try to find my preset idle. In general, it's very jumpy. And so far, I have done almost everything maintenence wise that I could do.

 

Dave, "you tried different combination of pins"? Which worked for you? I don't know, I followed the directions and got nothing.

 

Make sure your TPS is getting voltage from the ECU. Check all the pins on the plug itself and make sure you can find the 5 volt source for the TPS.

If the connector has a 5 volt source, yet you still can't get any readings from your TPS, then replace it. Your description of a hunting idle when the clutch is depressed is directly related to a faulty TPS.

 

I had to use the back probing technique with stright pins (described in the haynes) to set and check my TPS voltage.

 

But he is still going to get some type of reading though, right?

 

Update: I came home today, and tried to find a hint of the 5V signal sent by the ecu with no luck. I even tried the three pins exposed when the silver connector is taken off and found nothing. I asked my teacher today, and he said maybe check the fuses. Could the problem be this simple? Do you guys by chance know which fuse it is? I looked on the back of the fuse cover (near the steering wheel) and there were a couple labeled: Elec Parts. What would a bad fuse look like? Broken? Burned? Please keep the suggestions coming. I want to exhaust all other possibilities before blow $150.

No one would know the specific fuse # by chance...?

 

By any chance, do you have more info on this technique? Is is just using a different connector for the multimeter (I have two sets - the "crocodile" clamps and the long pins). Also, out of curiosity, are there 2 or three wires connecting everyone's TPS Silver connector? I only have two.

 

istead of asking what it would look like why don't you get your multimeter out and check the fuses... that would eliminate that possibility without having to post in the first place... if it's not the the problem then the sensor might just be bad... tried taking it out and cleaning it yet? i'd start there

 

I didn't realize you could clean it...Would carb/throttle body cleaner work? As far as checking the fuse (this is where I'm def. a nube), how do you check them? Which ones to check? Am I even looking in the right place (under the steering wheel)? I appreciate the help.

 

When I took mine out of the old car, at 100k miles it looked like brand new. The 5v signal would be checked on the connector, the brown one, not the sensor itself.

 

So you were doing it a different way other than what the website I provided (actually, what the faq's provided me)? It says to hook the multimeter up to the pins. If that's the case, that explanation is really misleading. I'm going to go right now to try to find that 5 V signal.

 

OK, I found my 5V source. Thanks for the correction Dave. It's a relief to at least have that said and done. I appreciate the help, guys. Since this website was slightly misleading, how do you guys suggest that I test for the resistance? Should I be hooking the multimeter up to the pins of the sensor, or to the connector? Is there another way I'm not thinking of?

 

So you were able to get a voltage reading? And from closed to WOT throttle the voltage changed correctly? If so then your TPS is fine.

 

Yes, I was able to find the voltage reading, the 5V one that is sent from the ecu to the TPS. But now my question is how do I check the resistance. If I follow the website, I should be connecting the meter to the actual pins on the actual black TPS, I won't be looking at the fluctuation in the voltage sent by the ecu, I'll be checking the return "signal" to the ecu. So basically I now need to know how to check this. I tried the way the website said to, and it didn't work, so I'm hoping one of you has a different way to do this.

 

I back probed mine to get a voltage reading at the TPS. Take two stright pins (the type for sewing) and stick them through the back of the TPS harness through the foam(still connected to the sensor). Slide one next to the back of the black wire and one next to the white wire. You won't be to see if your getting a connection with the pin, but you should be able to kinda feel if you made one. So then you have two pins sticking out of the back of the tps harness, which is still plugged into the TPS. Using the voltmeter touch the pos to the pin in the white wire and neg to the pin in the black wire. Make sue the key turned to the on position.

At close throttle you should get around .4 volts and at WOT you would get around 5 volts.

This procedure is supposed to be for those who only have one TPS sensor. Some cars have a TPS sensor and a WOT sensor.

 

Thats the info I needed. Thank you.

 

Are you setting the multimeter to read ohms or just leaving it on one setting?

 

I was setting the multimeter on the ohms setting when connecting to the pins 2 and 3 in the diagram, but was getting no base reading of 400 ohms at closed throttle. I'm going to go home today and try the back probing method that I30Mike described, and hopefully I'll get a reading. However, by doing it that way, I will still be reading ohms, right? Or will it be in volts? Either way, does this method tell me the same thing?

edit: before I was removing the brown sensor, and testing the pins themselves for the resistance in ohms without the connector on it.

Also, how would I tell if I have a WOT sensor too?

 

That should be 4 volts at WOT.

 

Yhea, Stephen is right. 4 vlots not 5. Sorry

 

Well, I did what was recommended, and it worked great. Very easy. I actually had to do it twice, because my car wasn't as warm as it should've been while doing it the first time. But my initial impression was good -- it didn't fall below idle once. When I went back under the hood, I remeasured to make sure everything was set, and found it lower, so after a few more adjustments, I got it at .40-.41 V at closed throttle, and at 3.97 V at WOT. Thanks go out to everyone who helped me out on this issue. My Maxima's little daily annoyances should be all done now. Again thank you.