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Throttle Position Sensor ( TPS )

Old 09-26-2008, 07:49 PM
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Throttle Position Sensor ( TPS )

i m suspicious about my TPS cuz ECU isnt throwing any codes and resistance on TPS is wrong....according to FSM if throttle valve is completely released there should be around 1 ohm and if completely depressed there should be around 9 ohms....but my thing is totally different...wen throttle valve is completely released i have around 9 ohms and if completely depressed i have around 2 ohms and ya one more thing wen i go up to 4000rpm my car cuts off like it jus wanna stop and dont wanna go that high....it means my TPS is gone? thanks
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Old 09-27-2008, 12:23 PM
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Originally Posted by burhan92SE
i m suspicious about my TPS cuz ECU isnt throwing any codes and resistance on TPS is wrong....according to FSM if throttle valve is completely released there should be around 1 ohm and if completely depressed there should be around 9 ohms....but my thing is totally different...wen throttle valve is completely released i have around 9 ohms and if completely depressed i have around 2 ohms and ya one more thing wen i go up to 4000rpm my car cuts off like it jus wanna stop and dont wanna go that high....it means my TPS is gone? thanks
What is important for TPS is 'smootheness' of its resistance throughout its range. It should't break the contact at any angle. Another important thing is the adjustment of the 'closed' throttle position. TPS has 2 more group of contacts: one is responsible for that zero point detection and another - for WOT. The second one is not used at all. I found the best way to adjust TPS is to hook up multimeter and measure resistance of the zero point contacts. You turn TPS with closed throttle to the position that the minimal touch to throttle opens that zero position sensor contacts. Automatic cars are very picky about this adjustment - if you mess it up it starts to slam into gears so hard that my wheels were slipping. I wouldn't believe that TPS could cause this if I didn't see it myself.

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Old 09-27-2008, 08:50 PM
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Originally Posted by Max_5gen
What is important for TPS is 'smootheness' of its resistance throughout its range. It should't brake the contact at any angle. Another important thing is the adjustment of the 'closed' throttle position. TPS has 2 more group of contacts: one is responsible for that zero point detection and another - for WOT. The second one is not used at all. I found the best way to adjust TPS is to hook up multimeter and measure resistance of the zero point contacts. You turn TPS with closed throttle to the position that the minimal touch to throttle opens that zero position sensor contacts. Automatic cars are very picky about this adjustment - if you mess it up it starts to slam into gears so hard that my wheels were slipping. I wouldn't believe that TPS could cause this if I didn't see it myself.
exactly max....u r 100% right....wen i put my car in D it slams like even i didnt take the foot outta da brake pedal yet it still slams like it jus wanna GO....its not smooth...i guess its my TPS den....thanks max
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Old 09-27-2008, 08:55 PM
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so this is a way u r saying to adjust TPS....connect multimeter to TPS sensor then move closed throttle position sensor with ignition on till i get around 1 ohm on multimeter? correct me if i m wrong....
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Old 09-27-2008, 08:58 PM
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Originally Posted by burhan92SE
exactly max....u r 100% right....wen i put my car in D it slams like even i didnt take the foot outta da brake pedal yet it still slams like it jus wanna GO....its not smooth...i guess its my TPS den....thanks max
You most likely only need to adjust it using the procedure I described. BTW, FSM is wrong - it recommends adjusting TPS based on its main sensor output voltage. I tried and couldn't get it out of my TPS for the life of me. Then I thought: "How would ECU know the zero point? There's even sensor for that ...". It worked from the first try. It seems ECU doesn't really care about absolute voltage much, it just needs correct zero point.
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Old 09-27-2008, 09:03 PM
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Originally Posted by burhan92SE
so this is a way u r saying to adjust TPS....connect multimeter to TPS sensor then move closed throttle position sensor with ignition on till i get around 1 ohm on multimeter? correct me if i m wrong....
You need TPS installed on TB. Then you have to disconnect connector of the closed throttle position sensor (CTPS). Connect your multimeter to CTPS and turn TPS around until you set it so that slight opening of the throttle opens the CTPS contacts.
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Old 09-27-2008, 09:04 PM
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wat is zero point
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Old 09-27-2008, 09:08 PM
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Originally Posted by burhan92SE
wat is zero point
Sorry, I invented the term myself - level of TPS voltage corresponding to the closed throttle. It varies from sensor to sensor, that's why it has adjusting screws.
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Old 09-27-2008, 09:13 PM
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Originally Posted by Max_5gen
Sorry, I invented the term myself - level of TPS voltage corresponding to the closed throttle. It varies from sensor to sensor, that's why it has adjusting screws.
just to make sure...u connect ur multimeter with the throttle position sensor then move the closed throttle position sensor and then where i get around 1ohm ( zero point ) i stopped there and tight the sensor screws..?
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Old 09-27-2008, 09:18 PM
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Originally Posted by burhan92SE
just to make sure...u connect ur multimeter with the throttle position sensor then move the closed throttle position sensor and then where i get around 1ohm ( zero point ) i stopped there and tight the sensor screws..?
TPS has 2 connectors - one for TPS itself and another - as FSM calls it 'Hard closed throttle position switch'. You need to connect multimeter to that switch connector. TPS connector can be connected into harness as usual, it is not even needed for adjustment.
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Old 09-27-2008, 10:40 PM
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Do you have a maintenance manual?
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Old 09-27-2008, 11:21 PM
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Originally Posted by burhan92SE
exactly max....u r 100% right....wen i put my car in D it slams like even i didnt take the foot outta da brake pedal yet it still slams like it jus wanna GO....its not smooth...i guess its my TPS den....thanks max
This could be something else, I was talking about gear changes 1->2 and 2->3.
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Old 09-30-2008, 03:57 PM
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The Transmission controller (TCU), uses the TPS to determine engine load, as you can imagine, with a wide open throttle, the transmission shifts at much higher RPM and also runs a higher line pressure to ensure there is minimal slip, at a small throttle opening, it shifts at lower RPM and runs a lower line pressure to ensure smooth changes. The TPS is the only sensor it uses for this. If the TPS is not adjusted correctly it will either shift too early and slip, or shift at high RPM and have harder shifts.
If your transmission appears to be shifting at the right RPM, but changes are very hard, I would suggest your TPS is not the cause, but the dropping resistor or a faulty line pressure solenoid in the transmission.
Either way, the TPS adjustment should be checked, as it is a fairly easy task.
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Old 09-30-2008, 07:52 PM
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Originally Posted by sonicii
The Transmission controller (TCU), uses the TPS to determine engine load, as you can imagine, with a wide open throttle, the transmission shifts at much higher RPM and also runs a higher line pressure to ensure there is minimal slip, at a small throttle opening, it shifts at lower RPM and runs a lower line pressure to ensure smooth changes. The TPS is the only sensor it uses for this. If the TPS is not adjusted correctly it will either shift too early and slip, or shift at high RPM and have harder shifts.
If your transmission appears to be shifting at the right RPM, but changes are very hard, I would suggest your TPS is not the cause, but the dropping resistor or a faulty line pressure solenoid in the transmission.
Either way, the TPS adjustment should be checked, as it is a fairly easy task.
ya i m jus not getting the time to check it...too busy now days.....but i will check it tomorrow for sure....and ya can someone post the picture of their TPS sensor position? i jus wanna compare it to mine before touching it....its an automatic....
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