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TPS diagnosing

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Old Jul 13, 2008 | 04:36 PM
  #1  
Jamaha80
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TPS diagnosing

I followed the steps here: http://vbxmaxima.8m.com/tps.html
because I have noticed a drop in/eratic RPM's while driving and while at idle. This is something I/my wife (it's her car, really) have been noticing for the last year or so and have gotten used to. At freeway speeds, sometimes the rpm's will drop down to 1k or less/normal idle rpm range, as if the tranny was put in neutral. Then they will pick back up and resume to "normal." I'm guessing it's a bad TPS. So, I get the 5v signal from the ECU, but NO resistance/ohms with pins 2 and 3. I mostly suck with electronics, but am I right in guessing that no resistance means the TPS is bad?

I'm seeing that it's not a cheap replacement part.. Best/cheapest place to source it?
Thanks
Old Jul 13, 2008 | 04:49 PM
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ebay. look for oem replacements. recently bought one for my sisters car for $70
Old Jul 13, 2008 | 06:14 PM
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Jamaha80
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What were your sisters symptoms, or how did you know she needed a TPS? I've been checking ebay but don't see any for the maxima.
Old Jul 13, 2008 | 07:12 PM
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her 04 sorento was shifting early, no power, and didn't downshift when floored.
TPS sensor code came up so i went by that and got it replaced, readjusted and all was good.

try maybe parts store or other online places that sell nissan parts
Old Jul 13, 2008 | 08:32 PM
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I have good resistance, but not the 5 V....bad wiring?
Old Jul 13, 2008 | 08:58 PM
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Jamaha80
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Originally Posted by Cheeshead
I have good resistance, but not the 5 V....bad wiring?
Are you probing the wiring harness or the pins on the actual TPS? For the ECU signal, you probe the harness, for the resistance you probe the TPS pins. At least thats how I understood it/what makes sense to me/what I did.
Old Jul 14, 2008 | 07:58 AM
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ahh, no I was checking the pin on the sensor, not the harness....I'll check that
Old Jul 14, 2008 | 10:23 AM
  #8  
Jamaha80
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I found out with my new multi meter that the TPS is probably shot. I'm getting ~2,800ohms at closed throttle, and ~4,800ohms at WOT. Apparently, the closed throttle value is supposed to be only 500 ohms. This makes absolutely no sense to me, and I would not be able to explain how more resistance in the TPS at closed/part throttle would affect anything. All I know is that the #'s arent right, so I guess I'll replace it. Thanks for the advice.
Old Jul 15, 2008 | 10:29 AM
  #9  
Jamaha80
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New news. That link I posted for how to check yout TPS is garbage. That is not the right procedure. The correct procedure is found here: http://forums.maxima.org/4th-generat...on-sensor.html

So I now know my TPS is in fact good, and have just saved $60.
Old Jul 15, 2008 | 01:40 PM
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Jamaha--

Let us know if you figure out the problem. I've had a similar problem for the last couple years, where the tach will drop to idle at freeway speeds. But I think mine is an overdrive problem, since it feels like it's falling out of gear when it does that (actually, it jerks a little when I give it gas and it goes back into gear). It's also been bouncing in and out of overdrive at freeway speeds.
Old Jul 15, 2008 | 03:09 PM
  #11  
Jamaha80
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The throttle angle the ECU recieves from the TPS will somewhat dictate how your tranny acts/reacts. I decided to order one anyways. After talking more with the infiniti tech today, he told me the TPS will likely crap out randomly and not typically just up and quit. This can make it difficult to diagnose. It's worth a shot. Go to www.rockauto.com find the TPS, and enter one of the 5% off coupon codes found here: http://www.retailmenot.com/view/rockauto.com
It ends up being $60 shipped! If it doesn't solve the problem you could easily get your money back by selling it considering they are hard to find for less than $75-$120 everywhere else.
Old Jul 16, 2008 | 01:52 AM
  #12  
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Originally Posted by Jamaha80
New news. That link I posted for how to check yout TPS is garbage. That is not the right procedure. The correct procedure is found here: http://forums.maxima.org/4th-generat...on-sensor.html

So I now know my TPS is in fact good, and have just saved $60.
I don't know about that Jama. All Keven97 says to do in that thread is to measure voltage. I disagree. I agree with the how-to on vbmaxima in that you should be checking the resistance (ohms) between pins 2 and 3 (.5 kohms closed, 4 kohms open). The part I have trouble with is measuring the 5 volts between pin one and ground. I gave up and stopped trying that on the sensor side and just measured it on the connector side. I stuck my probes in the 1 and 3 pins and got 5 volts. The Haynes and Chiltons have how-tos on this stuff anyway so we really shouldn't even need threads like this when a $15 manual covers it. ?? I much prefer/recommend the Haynes on this one though. In fact, I do believe Autozone often has the Haynes available on line. Let me see....
Yup, here it is: TPS install/adjustment how-to at Autozone.com (basically right out of the Haynes) Just ignore the 3rd gen. stuff.

I also like the Haynes because it covers the Throttle Position Switch (in addition to the Throttle Position Sensor) since they are both built into he same unit. Don't forget to check for continuity between terminals 5 and 6 on the switch.
Old Aug 31, 2008 | 06:38 PM
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Maybe I'm doing something wrong, but for the life of me, I cannot get a resistance reading off of my new tps,...my old tps as well for that matter.

I just replaced mine today. Went to a radio shack a few days ago and fetched a multimeter.

I followed the instructions on the vbmax site and a few other places, but no reading.

I set the meter to the horse shoe sign, turned car off, unplugged the tps harness closest to the passenger side, and tried pin 1 and 2, then 2 and 3.....nothing!


What am I doing wrong?
Old Aug 31, 2008 | 07:41 PM
  #14  
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Just wanted to mention, my throttle response is better.

Don't know if this is because my tps was warn out and a fresh one has restored it, or because I have it adjusted wrong.

Seems like my tranny feels different as well. Don't know if its good or bad. It seems too responsive to my foot?
Old Sep 1, 2008 | 01:45 AM
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Originally Posted by 2Broke4Better
Maybe I'm doing something wrong, but for the life of me, I cannot get a resistance reading off of my new tps,...my old tps as well for that matter.

I just replaced mine today. Went to a radio shack a few days ago and fetched a multimeter.

I followed the instructions on the vbmax site and a few other places, but no reading.

I set the meter to the horse shoe sign, turned car off, unplugged the tps harness closest to the passenger side, and tried pin 1 and 2, then 2 and 3.....nothing!


What am I doing wrong?
Do you have several different choices within the "horseshoe" section on your voltmeter?
Old Sep 1, 2008 | 05:40 AM
  #16  
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Originally Posted by ptatohed
Do you have several different choices within the "horseshoe" section on your voltmeter?
I don't. It says "auto on the screen so I am thinking it detects the range on its own. I see "OF" on the screen alot, while on the lower right hand of the screen switches from m ohms and k ohm in dication.

How bad could I mess my trany up if this is not set up correctly.

The best i could do was turn the tps so it does not rev out of control.

I unplugged the tps, set the idle to 700 rpm, shut the car off, reconnected the tps, and started the car again.

The engine was reving very high so I turned the tps until the revs came back down to around where I had set it, then fine tuned it with the iacv to 700 again.
Old Sep 2, 2008 | 07:43 AM
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Try to find one from FanaticRockford? He's a good guy.
Old Sep 2, 2008 | 03:50 PM
  #18  
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I already have a tps sensor.

Besides, this is one part i would not buy used, knowing that these fail all the time.
Old Sep 4, 2008 | 07:12 PM
  #19  
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Found out why I couldn't get a reading off my new tps sensor.

The brand spanking new multimeter I purchased from Radio Shack was defective.

I borrowed an ancient multimeter from an old man that I work with.

Worked like a charm.

got the settings to 500 ohms with foot off the gas and 4.2k ohms at wot.
Old Sep 4, 2008 | 09:28 PM
  #20  
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i have some laying around...
Old Sep 4, 2008 | 09:28 PM
  #21  
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pm me for a price..i ll for sure hook u up with a good price
Old Feb 1, 2009 | 05:51 PM
  #22  
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Hey everyone, I want to know if my tps is bad, i got a 4th gen manual and for some reason, when i start it up and drive, when i come to a stop, the car will idle at about 1500 for a couple of seconds then it will go down to about 950-1000, but recently, it's been staying at about 2000-2500. It's even to the point where i came to a complete stop yesterday and i put the car in first and took my foot off the clutch and the car started to roll with no problem....o, and this was going up hill also.......so can someone please tell me what the hell is my max doing, cuz i really love the car but this is pissin me off greatly... thanks in advance.
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