code 41... researched and tested

[suprra_girl]

so i've done the tests that jetjock suggests in another thread by testing voltage between idl & batt neg & resistance between e2 & batt neg and testing the tps itself and here are my results

IDL - Batt Neg = 10.7v (battery may be a bit low or i have slight voltage drop from battery relocation?)
E2 - Batt Neg = 0.02ohms

i have two tps' one is pre 89 and the other is 89+
pre 89 resistance of upper two pins = 0.07ohms
89+ = 0.02

moved the lever to 7 o clock on both
pre 89 = 1 .
89+ = 1 .

I have code 41, when tps is not plugged in i don't get the code. When it's plugged in i get the code. I tested the tps to see if the tems is working and when i turn the lever tems hardens and softens normally. That would suggest the tems side of the tps is working fine so i have a problem between the tps to the ecu? But.... upon thinking about this the tems would also use the same tps signal to the ecu so it should in theory have the same problem as the tps wire would just be separated into two wires but of the same originating wire, so if there was a problem to the ecu side shouldn't tems also see a problem?

I check VTA from the ecu to the tps plug and i have perfect continuity, if it was open i wouldn't have continuity and if it was shorted wouldn't i get a odd reading off it?

thanks for any help

 

[suprra_girl]

and so a resolution was found!

vta and vc connect in the tps in certain conditions... vc is also in the air flow meter
to get rid of code 24 i plugged in an air flow meter that had a 120kph meeting with a power pole... altho the afm was cracked... it got rid of air temp code but it seems it gave me a code 41 lol

So cliff notes... if everything else checks out... don't put on a naffed afm lol

 

[suprra_girl]

so i take back my last statement.... when it came back eng - ok i had the pre 89 tps in there... when i put in the 89+ i then get code 41... and both tps' tested out the same but yet when plugged in don't yield same results.. hmmmmmmmmm :s lol

oh for reference pre 89 tps is -- and 89+ is | for the lever direction, i was trying to use the 89+ | lever for the 1uz tb as that is the way the 1uz one is directed (almost, slight mod required for wing that tps sits on)

 

[jetjock]

I only see tests involving the IDL contact. That has nothing to do with a 41. Do this: Measure between VTA and battery negative. Do it both with the throttle (or TPS if off the car) closed and full open. Tell me what you get. I'd like to confirm voltages that would set a code 41 even though your TEMS test implies VTA is working.

Better still...

1) IDL must go from 0 volts to more than 1 volt as soon as the throttle is cracked. It must not remain at, nor return to, 0 volts at any time while the throttle is being manipulated off idle.

2) VTA must start out low with the throttle closed and increase as it opens. You should see around 100-300 mv when closed and 3.5 volts or more when fully open.

3) At no time can VTA be more then 4.8 volts or less than 0.1 volt (100 mv).

That's what the ECU must see at it's connector to run the engine properly and not spit codes. It's as simple as that.

 

[suprra_girl]

okie dokie shall check it out tomorrow

i will test both tps' and see what results i get
thanks jetjock

 

[suprra_girl]

so i started doing the tests and the pre 89 tps was checking out mint... i plugged in the 89+ and it all went psycho... but we moved the plug on the tps and it fluctuated back to normal readings, moved again get psycho readings... turns out e2 connection is nasty

am i right that e2 and e1 should both have continuity to ground?

 

[suprra_girl]

e1 & e2 have checked out now.. continuity is fine
i had a bad e2 connection in the tps connector and have now fixed that

here's my results from the test

Pre 89
VTA - Batt Neg
closed = 0.12v
open = 4.41v

IDL - Batt Neg
closed = 0.10v
Open = 9v thereabout.. will check again i had someone turning the tps for me

VTA - Batt Neg gradual
closed 0.10v
Open 4.26v

89+ (before repair of e2 terminal i was getting 5v)
VTA - Batt Neg
closed = 0.07
open = 5.51

IDL - Batt Neg
closed = 0.08v
open = 8v

VTA - Batt Neg Gradual
closed = 0.06v
open = 5.50v

Thanks

 

[suprra_girl]

so i happened to be messing around a bit more and i found that e1 and e2 are grounded fine......... till i turn on the ignition switch

 

[jetjock]

E2 is a sensor ground. It ends up being grounded to battery negative through the ECU. It must be a good connection or both VTA and IDL will not work. Since a poor connection on E2 will cause VTA to be high that alone could have been the source of code 41. That said as long as you're sure E2 is now good the 89+ TPS is out of limits. That's why you're getting a code with it and not with the pre 89. IDL is good on both parts.

If you ohm the VC-E2 and VTA-E2 section of the 89+ you should find one or both outside the resistance range of the TSRM spec. Regardless, the ECU isn't going to tolerate VTA being over 4.8 vdc and below 0.1 vdc as it is in the 89+. Either use the pre 89 TPS or get another 89+. It's either bad or the TPS isn't adjusted correctly on the TB so as to keep the closed voltage above 0.1 vdc.

You must have had the key on when doing the tests. If you have doubts repeat them referencing E2 instead of battery ground. Technically speaking since E2 is the sensor ground I should have had you reference it the first time but shouldn't be necessary.

 

[suprra_girl]

just measured against the tsrm and both are out of spec

pre 89
VC - E2 = 6.58ohms (Spec is 4.25 - 8.25ohms)
VTA - E2 = 0.13ohms (Spec is 0.2 - 1.2ohms)

89+
VC - E2 = 6.75ohms (Spec is 4.25 - 8.25ohms)
VTA - E2 = 0.05ohms (Spec is 0.2 - 1.2ohms)

I have perfect grounds on E1 & E2 with the switch off, once i go to ignition my grounds dissapear???

 

[jetjock]

Huh? I was under the impression you'd already tested them long before we got into this voltage thing. You know, when you were first trying to get ride of the code 41. Ah well.

Edit: No wait, those values look Ok to me. VC-E2 is supposed to be in K ohms though and VTA will vary as the TPS lever is turned. One of us is confused about how to use a meter and I don't think it's me

The resistance specs aren't important as long as the ecu sees the right voltage because voltage is what it works with. The 89+ TPS is not going to work unless you can set it so it's above 0.1 vdc when closed. In fact try manually holding it so VTA is above 0.01 volts (say around 0.02 volts) and see if code 41 disappears. It should.

How are you determining battery negative and E2 are the same? If you're testing for continuity between them that's likely not going to work with the key on. Measure the battery positive from each. You should get close to the same voltage. Better still set the meter to millivolts and measure between E2 and battery negative, just like you would when using ohms but use millivolts instead.

 

[suprra_girl]

yea i've got the tps thing sorted thanks to you... i know where to go from there

i was just curious as to my grounding issue... E1 when i check for continuity to ground should always be there right?

and E2 you say is switched to ground via the ecu

So with the switch off i should have continuity at E1 to chassis ground and nothing at E2. Then once i switch to ignition E2 should change to ground but shouldn't E1 still be ground?

I guess maybe i'm tired and i'll have another crack at testing the ground circuits tomorrow lol

 

[jetjock]

No, you may not be able to measure continuity between ground and E2 with the key on because of ground losses. Continuity can only be measured in circuits without power in them or your meter on ohms will lie to you. Better to measure voltage drop using millivolts the way I said.

Forget E2, I'm sure it's ok. Put whatever TPS on that, when adjusted as per the TSRM, falls between the VTA limits I specified in my post. Put it on the TB, adjust IDL like the book says and then measure the VTA voltage closed and open. If it stays above 0.1 volts when closed and below 4.8 when fully open you're good to go. If not get a TPS that does.

 

[suprra_girl]

ahhh now theres the catch hehe... i can't put it on the throttle body as i have a 1uz throttle body and it's not set up for a supra tps, i was trying to find info on the 1uz tps to see if it had the same values as a supra one and same plug and if so buy a new 1uz one rather than a supra one.

Ah k, no power = ok... with power starts getting messed up heh coolies

 

[jetjock]

Ok, good luck with it. One more thing: VC to E2 should always be 5 volts. It's the reference voltage for all the sensors. The first thing you should do when having a sensor problem is check VC. If it's not right what the sensor puts out will also be wrong.

 

[suprra_girl]

awesome stuff... thanks jetjock