Throttle Position Sensor (TPS) intermittent harsh gear changes and idle problems

[Kristian_Wraae]

Now you are being ridiculous.

 

You could just find the wires at the ECU end. They can easily be depinned. Then you check the resistance there.

 

Alternatively get two splice wires for the TPS plug. Your Toyota dealer should have those. Then you unplug the TPS plug and insert the splice wires and measure from them.

 

This is most likely at defect TPS and any garage can check that and fix it for £200 including a brand new TPS.

[Kristian_Wraae]

The most important thing to check is the VTA-E2 resistance with someone fully depressing the throttle pedal.

 

If the resistance is infinite or much more than 11.2 kOhm then the TPS is most likely dead.

[TubbyTwo]

Right, after a beer and a serious chill out I got back out there, the throttle body is off the car and I can now reset it as i can actually see the pins. The TPS is a working one as its from SRD so no issues there so it needs resetting with a multimeter first before I go looking at any wiring. one step at a time

[JasonR24]

Right, after a beer and a serious chill out I got back out there, the throttle body is off the car and I can now reset it as i can actually see the pins. The TPS is a working one as its from SRD so no issues there so it needs resetting with a multimeter first before I go looking at any wiring. one step at a time

 

Good to hear bud! It's frustrating but god damn it will be rewarding once you've fixed it!!

[mellonman]

Dont let it get you down bud just stick at it and chill when needed, but I know how you feel would hate to be a mechanic working in all them tight spaces

[Lee P]

Take the tb off to set the tps up its much easier

[Ian C]

If you still have problems come mid-march, I've got some days off free, so can have another look if you like. I've got some experience of multimetering these blighters

[TubbyTwo]

Guys im stuck with this bloody TPS adjustment. got the throttle body off the car, got the 0.60 feeler as per instructions probing the E2 pin with the negative and the IDL pin with the positive on multimeter. Multimeter is set to 200ohms, and I get the same reading no matter what I do it always says 1. nothing. If I move the TPS it jsut says the same reading 1. nothing.

 

any suggestions?

[TubbyTwo]

Guys im stuck with this bloody TPS adjustment. got the throttle body off the car, got the 0.60 feeler as per instructions probing the E2 pin with the negative and the IDL pin with the positive on multimeter. Multimeter is set to 200ohms, and I get the same reading no matter what I do it always says 1. nothing. If I move the TPS it jsut says the same reading 1. nothing.

 

any suggestions?

 

Right think I have it sorted. with the feeler gauge in it reads 1.

 

with no feeler gauge it now reads 0.00 so assume that's zeroed back to stock?

[Nodalmighty]

You will find doing a continuity test (Beep test) better than a resistance test. It should beep when contact is made and stop when broken. Beep test the E2 pin to the block to make sure it's earthing for a start. Your idl wire could be compromised or the idle contact in the tps could be shot so also do a continuity test between the ecu and the tps IDL connector. Also check for 5v on the power line and the resistance sweep between E2 and the TPS position signal.

 

A Dodgy E2 either at the block or the ecu will impact on nearly all the ecu's sensors in one way of another leading to some spurious engine performance issues. A downed IDL will lead to stalling, lack of fuel cut on over run (popping and banging) idle surge and possible judder and misfires under hard acceleration from low speed.

 

Lyndon.

[TubbyTwo]

OK thanks my multimeter doesn't beep so will have to find someone else to test it. How do i test the other parts? at the ecu in the footwell? Sorry I really am a complete simpleton when it comes to this stuff.

[shaz2010]

Just read the post from the start first time I've seen it. Gutted your having a right headache with it! I can't help in anyway but you have helped me. I had this problem when I bought my supra last summer and after a few months when I was starting the car in the morning letting it warm up, I would put the car into D and it would bang (jerk) into gear and when slowing down at traffic lights it was if the breaks were being applies ! I turned the car off then give it a few minutes thnking to myself that was strange (it didn't jump into gear after I started the car up again) but did a few days later the same thing.! So a read on here about fault codes and did the diagnostic test using the paper clip, code 41 flashed up(just like yours) so I took off the TPS unit cleaned it with WD40 and all of its connectors reset the ECU (by removing the battery) and started the car every thing was smooth and after a few starts and stops for a good few days testing I checked for faults and nothing! Never been any Fcodes since as I keep the paper clip in the car and check it every so often.. Hope you get it sorted like and it just needs TPS replacing ! I'm just thinking shall I replace mine :-/ in case I end up with the hassle you have ended up going through

[TubbyTwo]

Come back to this after having a few days away car has now been sat in bits for about 2 weeks as I now have a run around for day to day, danger is I need to fix the supra or it will just get left

 

So...

 

To the best of my ability I think the TPS is now centred although as per the instructions I cant get any reading when the throttle is spaced with a 0.60 feeler, tried 2 different multimeter's and both just read OL on the display through various settings. On both the original TPS and the one supplied by Lee @ SRD. Also I have no way to put a vacuum on the throttle opener as per instructions.

 

Remove the feeler gauge and I can now get readings but again either it just says OL or 0.00 so have manually centred the TPS and checked EL2 and IDL pins and it just reads 0.00.

 

Will fit back on car tonight, but not expecting it to make any difference.

 

Next up I guess is to try and work through the maze of wires with a multimeter OR as I'm off on holiday for a week soon just dump it at a garage and get them to look.

[TubbyTwo]

So after a month away from the supra and the forum due to hard study for a new Career which was stressing me out, Im back, with a clear head to get the Supra up and working again

 

Going to read through the last few pages again, have printed off some wiring diagrams and I'm going to get cracking this BH weekend. Have tried and test 2 TPS and both produce the same results, both give the same resistance readings so this leads me to think its a wiring issue.

 

Going to start at the ECU and make sure all the pins are making contact and test from there. Also going to try and source a spare ECU to swap and test to elimination that.

[TubbyTwo]

Also found this to work through

 

http://mkiv.supras.org.nz/articles/engine_2_41.htm

[Kristian_Wraae]

Did you try to run the car with the new TPS?

 

From what you write I understand that you can clear the codes and run the car for a while until the problem reappears and the code is set, right?

 

If so there must be an intermittent short or open in the circuit or in the TPS itself. In other words the TPS might mesasure out right but there can still be an intermittent open in the VTA E2 circuit inside the TPS.

[TubbyTwo]

Have run the car with 2 different TPS mate, both work fine for about 10 mins, then it goes back to same issue again and error 41 appears again.

 

Both TPS sensors have been tested off the car and the values are within the ranges in the service manual, both have been fitted and aligned with a multimeter correctly as per manual. so must be a wiring issue.

 

Tempted to try a brand new TPS but dont want to fork out £150+ if its not the issue. So need to learn to fault find with a multimeter myself.

[Kristian_Wraae]

I agree, it sounds like a wiring issue. Could be difficult to diagnose. You have to look for damage to the harness. It might be easier to run new wires one at the time. You could get new pins with a small piece of wire from Toyota for the TPS and the ECU and depin the wires one at a time. You have to check the wiring diagram though since some of the sensors share ground and 5V. You don't have any other error codes?

[mellonman]

i feel sorry for you mate , but still on a lighter note its not exactly supra weather out there, so it runs the same as the old auto box did yes/no?

[Kristian_Wraae]

I have checked the diagrams and the first thing I would do is to run a new wire directly from VTA on pin 43B on the ECU to pin two on the TPS. If you have no other sensor issues the most likely problem is a short or open in the VTA. It should be a yellow wire. If there are problems with VCC or ground (E) I would expect you to have problems with the subthrottle sensor aswell (and it would set code 47 too). Also the MAP sensor is depending on VC.

 

So depin the ECU pin 43B (the E9 plug - the one with the bolt) and the pin 2 on the TPS and get two new pin inserts from Toyota and solder a wire in between.

Edited March 26, 2013 by Kristian_Wraae (see edit history)

[TubbyTwo]

I agree, it sounds like a wiring issue. Could be difficult to diagnose. You have to look for damage to the harness. It might be easier to run new wires one at the time. You could get new pins with a small piece of wire from Toyota for the TPS and the ECU and depin the wires one at a time. You have to check the wiring diagram though since some of the sensors share ground and 5V. You don't have any other error codes?

 

Nope no other error codes stored, always code 41.

 

i feel sorry for you mate , but still on a lighter note its not exactly supra weather out there, so it runs the same as the old auto box did yes/no?

 

Tell me about it mate, however I now have a daily driver so that massively takes the pressure off fixing the Supra, plus last time I was also studying hard for a new Job and was stressed from that, which didn't help. So walked away from it for a month and ready to have another crack at it. Old autobox was toast, the new one is so much smoother (until the code 41 returns and it slams itself into gear)

 

I have checked the diagrams and the first thing I would do is to run a new wire directly from VTA on pin 43B on the ECU to pin two on the TPS. If you have no other sensor issues the most likely problem is a short or open in the VTA. It should be a yellow wire. If there are problems with VCC or ground (E) I would expect you to have problems with the subthrottle sensor aswell (and it would set code 47 too). Also the MAP sensor is depending on VC.

 

So depin the ECU pin 43B and the pin 2 on the TPS and get two new pin inserts from Toyota and solder a wire in between.

 

Ok thanks, don't suppose there is a part number for the pins? Haven't had error 47 its always 41 so that makes sense.

[Kristian_Wraae]

What I usually do is get the part number for the plug and then my guy at Toyota knows a way to find the pins for it.

 

These are the part numbers for the plugs and pins (as far as I can see)

ECU: plug 90980–11214 pin 82998–?

TPS: plug 90980–10711 pin 82998–12620

 

I can only find the pin for the TPS, but my local Toyota dealer could find the pins for the ECU too. They usually have most of the pins in store but better double check before you order. They come in short or long lead and the long lead usually rather expensive compare to the short lead.

[Robzki]

i'm sure its not, but could is it cold/ hot related rather than a 10 min drive issue? Do you have an afr gauge. I only ask as I'm not sure how the temps for the engine fuelling and gearbox changes are monitored. As in the engine thinks its cold so overfuels and the geargox thinks its hot so does some uber changes.

 

Hopefully you know what I mean. I'm never sure whether my autobox has an issue with my neck muscles sometimes

[Ian C]

The best place to start your hunt is at the pins going into the ECU, get in there right in the passenger footwell. You might need someone to help with moving the throttle to test, although you can work the accelerator yourself if you're desperate Check it with the ECU plug unplugged and the multimeter jammed into the pin, and then check it plugged in to the ECU with a pin probe through the wiring insulation.

 

If you don't see changes at the ECU end for IDL and VTA then swapping the TPS won't do anything, it is indeed a wiring issue. Then you can start the bigger moves like temporary wire runs that bypass the main loom. Or it might be a loose pin in the ECU plug and you can quickly refurb that.

 

Also, you could try getting the engine idling and then mauling around the wiring loom at the ECU end. Bend it, twist it, waggle the plug, that sort of thing. If you hear the engine note change while doing this, or any other odd behaviour, chances are it's a problem with loose connections at the ECU.

[Kristian_Wraae]

I think that since it is an intermittent problem there is connection most of the time. It'll only take 0.5 s of short or open to set the code and if he can drive it around for 10 mins or more before the condition is met multimeters are not going to find the problem. I still think that it must be a problem with VTA and simply running a new wire will tell us if that indeed is the problem. If running a new wire solves it he can try to find the error or just be happy with the new wire. When that is said I have previously had trouble with the pins of the ECU connector comming loose and it could be a simple thing like that so: When you get the plug of the ECU remove the yellow cap and check that the pins for the TPS are all locked in their seats.