zachb55

Hey there folks, first off I wanna say this place rocks, been reading and learning since before I inherited (for a price) the family 4Runner last December. After driving it for a year with a tranny that takes about 10 minutes of warming up to shift into OD, and doesn't like to shift back out, I am finally tackling the problem. I would love to just swap in a manual transmission, but being a college student in an apartment, that ain't gonna happen for a bit. I've got 10 years of mechanical experience, so I can handle the tech terms so please lay it on me.

Heres my approach to the problem so far. I checked the codes, expecting (and kinda hoping for) a solenoid to be faulty, but the codes don't show that. Instead, it threw a code 41 from the CEL and so immediately I started diagnosing the TPS (Code 41 = TPS issue). So I tested first at the ECM, getting very poor OHM readings from all but one wire-wire combination. Next i removed the TPS and got the same results, basically telling me the TPS is faulty. My question is first, does anyone know if a parts house can test a TPS more definitively like they can a Alternator or something like that? I just don't wanna buy a new one and have no change. I know the tranny problems can be related to this, so any input is much appreciated. Any one else find that replacing the TPS helped with OD problems? Thanks again for all the info i've been absorbing so far.

-Zach

thook

How did you run the test? What were your readings?

I don't believe I've ever been to an auto parts house that would do something like testing a TPS, much less know how to. But, that doesn't mean it's not possible. I've just never asked. I've always done it myself once I learned how. The only way to really test one, though, is with an ohm meter whether it's testing against resistance or voltage. There aren't any special machines for it, if that's what you're asking.

Flash319

There is not that much to testing a TPS. Follow a manual (hays) and it will guide you through it. All it is, is a variable resistor and a switch. One set of contacts are for the variable resistor and should smoothly change resistance as you turn the throttle, no jumpy spots. The other is the IDLE circuit that tells the ECU that you have no throttle applied. When the throttle is closed, you should get a closed switch (very little resistance, like under 40 ohms or so) and when you just start to open throttle it should jump to a very high resistance (infinity) as the switch opens. There is one other circuit on there and am not sure its purpose. Maybe someone else knows?

thook

I believe you're referring to the VTA circuit? The throttle angle....

https://www.yotatech.com/forums/f116...or-cel-129413/

thook

Read....

"Seemingly unrelated systems can also be affected by a malfunctioning TPS, including Electronically Controlled Transmissions (ECT). Problems can include poor shifting and hunting between gears due to the engine computer seeing apparent throttle position changes coming from a flaky TPS."

http://www.4crawler.com/4x4/CheapTricks/TPS/index.shtml

zachb55

Yeah i was using manual procedures with an electric multimeter, taking ohms readings. I didn't write them down, but the only one to pass spec was the VTA - E2 circuit at about 5.4 K-ohm, nothing else gave a decent reading. I just know that where i used to live the Napa would test just about anything, always had a machine for it... i think im just second guessing my results cause i dont wanna choke up a 100 bucks. has anyone ever solved their tranny problems by replacing a faulty TPS, on this board? i understand how they'd be related, and it seems to fit my scenario, thanks for the input

sparkthis

had same problem same code 41 searching for gears tested tpsensor tested fine i replaced today and truck runs good