Supra Dr

iTrader: (14)

Sounds like the throttle body is bad. (cheaper to buy a used complete 1 than to try
different sensors) You can try & clean the throttle body - worth a shot. Disconnect
the battery 1st, do not spray inside it (spray a rag or tooth brush) & DO prop the plate
open w/ a wood/ plastic tool handle. The throttle plate is on a geared motor & WILL
bite you.
The cable going to the throttle body is for limp home only - so your not stranded in the
middle of the road. Newer versions of fly by wire have deleted that cable all together.

MD99SC300

From what I read it is hardly ever the throttle position sensor. Usually it's the accelerator pedal position sensor or the throttle control motor. I just ordered a used TB and plan to change out those parts. We'll see what happens.

VoidsGTO

Where is the accelerator position sensor located at? Is it the one closest to the actual TB and wire? I'll look into used throttle bodies and see what I can find on ebay. I saw the video and checked everything on the car which seemed normal. It was snapping back when opening the throttle 100% and I didnt hear grinding or friction. in the pdfs attached telling the steps to check the voltage (p1120 I think) where is that box located? I pulled off the lower instrument panel under the steering wheel and wasn't sure where it was. I saw a box with a lot of wires in it but it wasnt exactly that same as the diagram.

MD99SC300

The accelerator position sensor is this one, closest to the firewall:



As for the box they speak of on the PDF, that's the ECM (ECU) located on the passenger side underneath the carpet (atleast on the SC300 it's there). You should check all the voltages on the sensor PINs before checking the ECM though (VPA, VPA2). Thats the way the manual says the troubleshoot.

VoidsGTO

Thanks for the pic, that was the sensor I was thinking it was. I'll keep looking for the box to check the voltages since I'm not sure which car the attached pdfs refer to. I did get a used TB on ebay for ~$140 shipped, does that seem like a decent price? It doesnt have the TPS though but since more than likely mine is still good I'll just swap that. I also bought a new TPS from autozone as a backup so I feel one way or another it will work out.

tjmhillz

iTrader: (6)

I would check around on the forums or check to see if somebody is parting out a engine. I bought a complete tb without tps for 80 shipped.

VoidsGTO

TJ were you having the same issues with power loss? I already bought the TB with the APPS and motor, and was planning on reusing the stock TPS thats on the car now and hope that eliminates the problem. MD have you solved the issue with the other TB?

MD99SC300

So I made an attempt to remove the Throttle Control Motor with no luck. As you can see from the picture below, I was able to remove the top screw but the two bottom screws are stubborn as hell!!! I used a great screwdriver too and nothing, they both ended up getting stripped! I'm so pissed, I think I would be better off just replacing the whole TB. Anyway, it's dark now, I think tomorrow I'll try replacing the APPS instead since that seems a little easier to do. If that fixes my problem then I dont have to worry about the motor, if not, I guess I'll have to come up with something to remove those two screws.

tjmhillz

iTrader: (6)

Yea those screws are stubborn and soft. I ended up stripping a few as well lol.

MD99SC300

So I successfully replaced the Accelerator Pedal Position Sensor and drove the car around for about 40 minutes and NO engine light and NO limp mode so it may have been the APPS that was bad. I'm going to keep on driving it and hopefully it doesn't come back. I'm so glad I didnt have to replace the Throttle Control Motor because I dont know how I was going to remove those stubborn screws.

MD99SC300

Been driving the car for a week and nothing so the APPS fixed the issue. Just wanted to let everyone know that if you ever suffer the same symptoms it is most probably the APPS.

VoidsGTO

Thanks for the update. So far I got the used TB from ebay but I'm pretty sure I got a bad one. I'm still throwing the code but its even worse after installing the ebay TB. As soo as I tried to start the car it revved up to almost 4k rpm and wouldnt idle steady at all. I adjusted the TPS but could only get it to keep idel at about 2k rpm. Then I started throwing the P0120 and P1120 code like neither the APPS or TCM were working. Any suggestions? I'm checking local junk yards for the part and have a new TPS from autozone here. I'm pretty sure its the APPS, not the TCM as MD99 was having the same issues. Anythine else I should try? Does it sound like I'm doing thinks right? Thanks

tjmhillz

iTrader: (6)

What is your tps set at and did you reset your ecu?

durtysc300

The issue is the Accelerator Pedal Position sensor..replace it and you should be good to go!

VoidsGTO

Well we did a combination of things trying a new TPS from autozone, then trying to make one good part from the 2 throttle bodies and nothing worked. Even with the TPS at the lowest CW position it still reved at 2k rpm at idle. Of course if I adjusted it CCW it would rev even higher because it was opening the throttle body. I contacted the seller from ebay and he is sending me another complete TB with the APPS, TCM and TPS on it and it has been tested and off a working car. I'm going to try again this weekend when I get the part. One thing I did notice which seemed odd was the voltages across the different sensors. With the key in the on posisition I was reading 5v reference from the ECU on the APPS and TPS, but only 1V reference for the TCM. Does this seems right? Most of the time its always a 5v power but I'm not sure on this car. If this new TB doesnt work I'll be hunting down a short somewhere in the wiring which I hate doing.