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If I installed it wrong would it throw a code? Will the car not run? Cause the car runs ok with no codes right now, right now the TPS is all the way to one side and can't be adjusted anymore.
I would think it would throw a code but there is a specific method of installing which is why i asked. I gave you the specs so i would also see what you have when the gas pedal is fully pushed. 0.68v is acceptable at rest which is why it probably isn't throwing a code, but have you worked the throttle to the maximum? I wonder if it will fault at a higher rpm. You should be able to go lower in voltage slightly.

Edit: i checked mine and it's right in the middle. If you cannot get the voltage to drop below what you have now i would think there's something wrong with it, providing you put it in there in the most clockwise position and turned back counterclockwise.
 
I would think it would throw a code but there is a specific method of installing which is why i asked. I gave you the specs so i would also see what you have when the gas pedal is fully pushed. 0.68v is acceptable at rest which is why it probably isn't throwing a code, but have you worked the throttle to the maximum? I wonder if it will fault at a higher rpm. You should be able to go lower in voltage slightly.

Edit: i checked mine and it's right in the middle. If you cannot get the voltage to drop below what you have now i would think there's something wrong with it, providing you put it in there in the most clockwise position and turned back counterclockwise.
My TPS is all the way turned to the right with no more adjustment down, i took it out and reinstalled again per your instructions and same thing. Does our car have an idle up switch? If there is where is it? My friend was asking due to the nature of my problem. When the fans turn on sometimes the car will drop really low idle, or sometimes the car will just die. But only when the fans turn. I try checking on the other things you asked for in a little bit.
 
My TPS is all the way turned to the right with no more adjustment down, i took it out and reinstalled again per your instructions and same thing. Does our car have an idle up switch? If there is where is it? My friend was asking due to the nature of my problem. When the fans turn on sometimes the car will drop really low idle, or sometimes the car will just die. But only when the fans turn. I try checking on the other things you asked for in a little bit.
Well then yours doesn't sound like it's working. I was hoping you checked the range of voltage to see if that even fell within spec. You should see lower than 0.68v when turning that counterclockwise. $57

2002 LEXUS IS300 Throttle Position Sensor (TPS)

I would think you would throw a CEL if it wasn't working properly though. Doesn't make much sense as that's how it's installed. I'd be curious what % throttle opening you can dial in. I even checked mine, never touched it and sits in the middle of the slots.

The idle is controlled electronically therefore messing with the APPS or TPS won't help you. It should idle 700±50 rpms at idle and 750±50 rpms with AC on. I'm not saying for sure your part is bad, but with it installed right(like what you did), you should see lower voltages.
 
Well then yours doesn't sound like it's working. I was hoping you checked the range of voltage to see if that even fell within spec. You should see lower than 0.68v when turning that counterclockwise. $57

2002 LEXUS IS300 Throttle Position Sensor (TPS)

I would think you would throw a CEL if it wasn't working properly though. Doesn't make much sense as that's how it's installed. I'd be curious what % throttle opening you can dial in. I even checked mine, never touched it and sits in the middle of the slots.

The idle is controlled electronically therefore messing with the APPS or TPS won't help you. It should idle 700±50 rpms at idle and 750±50 rpms with AC on. I'm not saying for sure your part is bad, but with it installed right(like what you did), you should see lower voltages.
Heres a couple of pixs, in the second pic does anyone happen to know what this cover is for?
 
I checked my TPS with a multimeter and its reading .001 with ignition on. car drives fine though it just has problems with 20%-100% pedal feathering. am I doing it wrong? tps dead? I stuck that probe all the way down and grounded on the intake mani like this guy
 
I checked my TPS with a multimeter and its reading .001 with ignition on. car drives fine though it just has problems with 20%-100% pedal feathering. am I doing it wrong? tps dead? I stuck that probe all the way down and grounded on the intake mani like this guy
It sounds like either your meter test probe did not make contact with the white/red wire or your meter wasn't configured correctly. Try verifying your meter is good by making sure your meter reads 12.5-13.1vdc by simply testing the battery, also verify your meter setting can read less than 1 volt(which it should on any DC voltage setting). As an electrician of many years, you should always self check your meter before taking any reading by either checking a known live source or put your meter on ohms, short the two test leads together and verify your meter reads 1 ohm or less. If you don't have a backprobe you can push the meter lead into the end as shown or what I've done in the past, pierce the wire right before the TPS with a needle and read off the needle(just another way without a backprobe). I highly doubt your TPS is bad or that you really don't have any voltage unless the car is throwing multiple range/performance DTC's relating to the TPS and the driver by wire algorithm would fault(limp more and butterfly stays cocked). So what I'm suggesting is to redo your test, I bet you will have a different result. Obviously make sure ignition is on/car not running. You have four wires, VTA signal, VTA2 signal monitor, E2 which is brown ground and +5vdc which is blue/yellow. You should also have the specs pointed out below with the pedal pushed and not pressed.

For TPS....from the ECU('02+)
VTA(white/red) connector E7 pin 25
VTA2(green/yellow) connector E7 pin 24
VC(blue/yellow) connector E4 pin 35 **5v source**

Remember the solid brown in this car means engine sensor ground for the most part and should read less than 1 ohm to ground. Readings ohms between VC-E2 on both sensors should read 1200-3200 ohms @68*F. The voltage you should read is following..(to ground, E2, or brown wire)

TPS(diagnostic spec ratings)
VTA (pedal not pushed) 0.4-1.0v
VTA (pedal depressed) 3.2-4.8v

VTA2 (pedal not pushed) 2.0-2.9v
VTA2 (pedal depressed) 4.6-5.1v

VC is always around 5 volts which is your supply voltage, E2 is always ground. Maybe check these two pins to verify you read that the TPS is getting +5vdc power. I don't even think your car would run if VTA read 0.0 volts. Hope this helps, I bet you will get better results and let us know how it works out. Sorry for the book and I just wanted to throw all the real spec data available so you know and I wanted to include this information in this thread for you and others.
 
It sounds like either your meter test probe did not make contact with the white/red wire or your meter wasn't configured correctly. Try verifying your meter is good by making sure your meter reads 12.5-13.1vdc by simply testing the battery, also verify your meter setting can read less than 1 volt(which it should on any DC voltage setting). As an electrician of many years, you should always self check your meter before taking any reading by either checking a known live source or put your meter on ohms, short the two test leads together and verify your meter reads 1 ohm or less. If you don't have a backprobe you can push the meter lead into the end as shown or what I've done in the past, pierce the wire right before the TPS with a needle and read off the needle(just another way without a backprobe). I highly doubt your TPS is bad or that you really don't have any voltage unless the car is throwing multiple range/performance DTC's relating to the TPS and the driver by wire algorithm would fault(limp more and butterfly stays cocked). So what I'm suggesting is to redo your test, I bet you will have a different result. Obviously make sure ignition is on/car not running. You have four wires, VTA signal, VTA2 signal monitor, E2 which is brown ground and +5vdc which is blue/yellow. You should also have the specs pointed out below with the pedal pushed and not pressed.

For TPS....from the ECU('02+)
VTA(white/red) connector E7 pin 25
VTA2(green/yellow) connector E7 pin 24
VC(blue/yellow) connector E4 pin 35 **5v source**

Remember the solid brown in this car means engine sensor ground for the most part and should read less than 1 ohm to ground. Readings ohms between VC-E2 on both sensors should read 1200-3200 ohms @68*F. The voltage you should read is following..(to ground, E2, or brown wire)

TPS(diagnostic spec ratings)
VTA (pedal not pushed) 0.4-1.0v
VTA (pedal depressed) 3.2-4.8v

VTA2 (pedal not pushed) 2.0-2.9v
VTA2 (pedal depressed) 4.6-5.1v

VC is always around 5 volts which is your supply voltage, E2 is always ground. Maybe check these two pins to verify you read that the TPS is getting +5vdc power. I don't even think your car would run if VTA read 0.0 volts. Hope this helps, I bet you will get better results and let us know how it works out. Sorry for the book and I just wanted to throw all the real spec data available so you know and I wanted to include this information in this thread for you and others.
Turns out i have no idea how to use a multimeter. I got the voltage it was .73 and I put it to .65. First was idling low then settled in the normal after driving around a bit. I'll update once I have a chance to test out feathering the throttle while drifting.
 
Turns out i have no idea how to use a multimeter. I got the voltage it was .73 and I put it to .65. First was idling low then settled in the normal after driving around a bit. I'll update once I have a chance to test out feathering the throttle while drifting.
No problem, we all make mistakes. 0.71vdc is OK and you may have been fine there. Lowing the voltage or really resistance will drop idle for a moment but the ECU will correct for that and will target 700±50 rpms in park(operating temperature). If there was a dead spot in either the TPS or APPS you would most definitely have at least one code. Not to mention the drive by wire algorithm will fault and the butterfly will be slightly locked in a cocked position(otherwise known as limp mode). It wouldn't hurt to verify you get the min/max voltages I have posted, so you know the TPS is putting out a linear increase. I have the APPS specs posted too, so if you need them I'll post em.
 
alright I'll get those voltages tomorrow. today I was beating on it and lost all throttle during a drift after going 100% and letting up to around 30% then trying to mash it back down to 100 i lost all power. Also I got p0121 and p0122. also managed to get a p0300 but i suspect that's because im running 8psi on emu and was laying on the rev limiter doing a standing burnout for 30 seconds.
 
alright I'll get those voltages tomorrow. today I was beating on it and lost all throttle during a drift after going 100% and letting up to around 30% then trying to mash it back down to 100 i lost all power. Also I got p0121 and p0122. also managed to get a p0300 but i suspect that's because im running 8psi on emu and was laying on the rev limiter doing a standing burnout for 30 seconds.
Okay, yea the misfire may be irrelevant but since you threw two codes specifically to the TPS signals you may have a bad TPS. So that's why I would verify your VTA1 and the VTA2 monitor signal. ALSO, make sure your connector is not loose, I have read about that causing an issue more than once as well as heat soak. Make sure your throttle body wiring is good. I found this from another thread that may help and breaks down why these codes were thrown. Wouldn't hurt to do a static resistance check across the TPS as shown below. Worst case and it's not the wiring, a new quality TPS can be had for about $60. I also Pm'd you with some extra info that may also help.
You need to inspect or check the other end as well at the ECM plug, just to ensure a good connection. If you threw a new TPS part in I would be looking at the probability that the harness and or connector needs a closer look.

Like Jason says - if the electrical values are out of wack - then this necessitates a replacement TPS - chances of a partially open TPS sensor is slim if you put a new one in and the fault is repeating.

Check the pinout voltages first. Your specific code is related to pin out VTA1


Determine if the following information is beyond your capabilities: Here is the diagnostic process or troubleshooting info from Lexus:


The ECM uses throttle position sensor to monitor the throttle valve opening angle.

There is a specific voltage difference expected between VTA1 and VTA2 for each throttle opening angle.

If the difference between VTA1 and VTA2 is incorrect, the ECM interprets this as a fault and will set a DTC.

VTA1 and VTA2 each have a specific voltage operating range.

If VTA1 or VTA2 is out of the normal operating range, the ECM interprets this as a fault and will set a DTC.

VTA1 and VTA2 should never be close to the same voltage levels.

If VTA1 is within 0.02 V of VTA2, the ECM interprets this as a short circuit in the throttle position sensor system and will set a DTC.










Digger08
 
on vta to e2 resistance i got 1.3 and vta2 to e2 resistance i got 1.6 on tps. both under the range of a good tps.

TPS(diagnostic spec ratings)
VTA (pedal not pushed) 0.035 (??)
VTA (pedal depressed) .035 (??)

VTA2 (pedal not pushed) .01 (??)
VTA2 (pedal depressed) .01 (??)

I probably didn't measure these correctly

I did then measure random pins in the general area of the picture (couldn't zoom in on laptop) and got almost on 5.0v for ones that gave readings.
 
Well didn't you say the connector for the TPS is no good and won't lock on? I've read on a number of occasions it was the actual connection and not the TPS. Although, the bad connector may have burned up the TPS, not sure. Your resistance is low but that spec is also taken at a temperature of 68°F. If the temperature is colder where you're at, the ohmic value will drop slightly too. So your TPS may be fine buy you lack the physical connection between all four pins(which would give you 0 volts).
 
Well didn't you say the connector for the TPS is no good and won't lock on? I've read on a number of occasions it was the actual connection and not the TPS. Although, the bad connector may have burned up the TPS, not sure. Your resistance is low but that spec is also taken at a temperature of 68°F. If the temperature is colder where you're at, the ohmic value will drop slightly too. So your TPS may be fine buy you lack the physical connection between all four pins(which would give you 0 volts).
sorry jason i was mistaken the connector is fine. its 77 degrees out today and the sensor was even hotter because i just drove around.
 
I gotcha. Okay, FSM page 250 says disconnect the TPS and read the resistance between the bottom(VC +5 input) and the top pin(E2 ground) as you look directly at the pins. Spec is 1200-3200 ohms @68°F.

Regardless, if you are sure there is +5vdc on the blue/yellow VC wire and ground is good, you theoretically should have voltage outputs on both VTA and VTA2 middle pins. Do you have it on the connector(+5v) with the ignition on and reading the TPS connector two wires? I would try to disconnect the TPS and give it +5vdc on VC and E2 ground and move the throttle wheel and read the middle pins to ground to see if there is an output on any of the two, if you are able/want to do that. Otherwise if you are sure the connector is good and the TPS has right power supply(between VC-E2) then the TPS would have to be bad. I just like to double check and rule out something simple before wasting money but it sounds like you know what you're doing and following me. Hate for it to be a bad connection which is what I originally had thought.
 
I gotcha. Okay, FSM page 250 says disconnect the TPS and read the resistance between the bottom(VC +5 input) and the top pin(E2 ground) as you look directly at the pins. Spec is 1200-3200 ohms @68°F.

Regardless, if you are sure there is +5vdc on the blue/yellow VC wire and ground is good, you theoretically should have voltage outputs on both VTA and VTA2 middle pins. Do you have it on the connector(+5v) with the ignition on and reading the TPS connector two wires? I would try to disconnect the TPS and give it +5vdc on VC and E2 ground and move the throttle wheel and read the middle pins to ground to see if there is an output on any of the two, if you are able/want to do that. Otherwise if you are sure the connector is good and the TPS has right power supply(between VC-E2) then the TPS would have to be bad. I just like to double check and rule out something simple before wasting money but it sounds like you know what you're doing and following me. Hate for it to be a bad connection which is what I originally had thought.
how do I check ground on the brown wire?
blue and yellow i get 5v. both VTAS i get barley anything. My harness hasn't been messed with all the way up to the p&p harness from tokensolutions for the emu
 
how do I check ground on the brown wire?
blue and yellow i get 5v. both VTAS i get barley anything. My harness hasn't been messed with all the way up to the p&p harness from tokensolutions for the emu
To check for ground on your brown wire(E2), simply put your meter on lowest ohm setting and put one meter test lead on the wire and one test lead on the block. The intake manifold has some brown wires terminated on the 12mm bolts and I believe one of them is the TPS with other sensors. All white/black stripe and solid brown wires on this car should ALWAYS read continuity to ground(meaning one ohm or less OR whatever your meter reads for ohms when you self check by shorting the two meter leads together). Most high end meters read 0.2-0.0 ohms while other read near an ohm when checking ground or shorting the meter leads(meter lead resistance).

You should be able to clock the TPS or butterfly by turning the throttle wheel and you should get the two output voltages with 5v and a ground given. If you are not and have power as mentioned, then i would say the TPS is bad for sure. This is providing you are sure the connector is good and you are making contact with the harness wires. You can also read at the ECU by using a backprobe, I've even used needles to read certain pins or up waterproof sleeves on connectors because meter leads can damage the seal on any waterproof connector.
 
i tested it from the p&p harness and i get the same 5v. i guess its just odd im not getting signal from the harness with ignition on? could it be an EMU thing? either way my TPS is out of spec so i'll replace it. which one do you recommend going with? i see multiple brands for the 60 dollar range
 
Sounds like a ground issue if you have 83 ohms on it and not continuity. Make sure you get an accurate reading. I can't say what those things in the pics are. Looks like audio stuff and I would remove it if it's not needed. Main thing is that brown wire needs to have a good ground, it makes sense why it wouldn't output anything.
 
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