Code :1120 "Accel. pedal pos. sensor circuit failure" ..FIXED!!!!

[edgy]

been gettign thsi error light once i na while before ... NOW it is happening all the time ....


...on the way home from EOS, the CE light goes on & i lose throttle control over the engine... the car runs fine but i have no gas pedal... it did it every 15-20 min or so & like 9-10 times on the way home the last 150 miles... & it has happened literally every time i drive the car now....

Everything will be fine & then it will suddenly go out on me ... no warning... no indicatrions of what it causing it... hot days, cool evenings, long drives, short drives... no matter i lose all throttle control but for the last tiny little bit.... it appears that the DBW is totally failing....??


so i found my doggone reader & checked the code...

1120

"Accelerator position sensor circuit malfunction"

WTF do i do now....?
I assume this is a TPS type sensor...?

WHere is it...can i just replace it or something...?




HELP! thanks !!!





PS HERE is a REALLY GOOD site for Code lookup... the old thread SEVEN posted is now dead....

Lexus OBD-II Trouble Codes

[Bgadidas10]

Hmm that's weird. I'm pretty sure you right with a TPS sensor. Hopefully someone can shed some light. Oh by the way, nice find on that page of codes!

By the way, what ever happened to Sean (Seven)? I literally have half of his old N/A car on mine. (Intake, headers, exhaust) I haven't heard from him in years.

[edgy]

found some more info..

apparently the "Accelerator Pedal Position Sensor " is most likely inside here on this 80MM TB on my car... based on thsi info from LAmbchop...



"From the repair manual, it's located here on the OEM IS TB but since you're using a GS400 throttle I'd suspect it's in a similar location.

[edgy]

apparently ... on the GS300-400 80mmTB's the black part in the top pic above is the part I am thinking I need to replace or figure out how to fix..

going from the schematic above of the IS300 TB... the 80mm TB i have should have an "accelerator pedal position" sensor in the same spot, & if the OEM IS ECU is telling me that there is a problem with an "Accelerator Pedal Position Sensor" based on the code it is throwing....

it appears i have to replace or repair the sensor in the throttle cable bracket on the 80mmTB i am using....




any one else have any other ideas...?

[edgy]

ANALysis:



1st, i swapped in the new/used APP sensor part with the throttle cable bracket etc everything that pops off when you take off the 3 large phillips screws.....

4 days later, I experienced the fault again, same deal...no power no throttle 2k idle ...'till i reset the ECU.....


Next ... I decided to swap out the OEM IS300 TPS sensor for the used TPS sensor that came with the spare GS TB..... there is very little difference & I think the part numbers are actually the same....


I got a tip from another thread on the voltage setting you want the TPS sensor to be sending
I assumed that meant when the car was warm, & idling,??.... then i realized that my greddyInformeter gives me a throttle voltage reading option, so I tried setting the TPS sensor to the .72v at idle......

it floats a bit... but i was solidly at .70v-.72v when i stopped playing with it....


It is freekin tricky.... a TOUCH past the critical point & the thing trips open into Limp mode & you gotta reset the ECU again... but it was interesting to be able to re-create EXACTLY what happens when i am driving it & i lose the throttle.

After buttoning it up I ran it around a bit today.... NO problems.... i am not sure if it is FIXED... but i think so.... the Voltage reading on the TPS sensor before when warm was .64v.(!).... so it was definitely off..... i thot maybe it was shifting or the screws were loose when it started going nuts a few weeks ago...but nothing was obvious, the screws were tight.


I think basically when i originally installed the IS 300 TPS on the TB... i had no clue about setting it up &, & looking for a specific voltage Etc... i just fuggin eyeballed it & screwed it on... it was blind luck that the car fired up & ran ok knowing that now...

..evidently it was set ok, but SOO close to being off...that it would trip once in a while due to anything from thermal expansion to gremlins etc....who knows....that would explain why it would be fine for months & suddenly trip....... maybe the EOS trip & that blast to 125+ for a while was enough vibration & heat to make something shift in there & the thing started tripping all the time...?



God i pray...

There's nothing worse than going dead stick on the freeway or hiway with a big ass truck behind ya & no shoulder......

[Mrcs007]

Still working right? There is a diff between Accel pedal pos and TPS. They compare the two values to set your throttle plate position.

[edgy]

DO you have any advice or info on how to " set" them properly..? is there a " procedure"

... or do i only worry about setting the TPS sensor properly...?

I just loosened the screws & moved it a hair at a time & kept checking the TPS voltage reading until i got to .70-.72v....

is there any thing else i need to do for these damn sensors ???

[RIALTO MIKE]

is this a two wire sensor? ive never taken mine off so i would have to check to be sure. but if so, you should be able to run the sensor and use a VOM to check the resistance in the circuit and the signal going back to the ecm. if you operate the sensor very slowly you may be able to see it shorted. you can do it with it plugged in to the harness as well using whatever it is that you are using to see the voltage setting. the lowest you should see is .5 volts and the highest you should see is 4.5 volts since this is the usable range for the circuit from 0-5 volts. if you move the throttle slowly and watch it you may see the voltage drop to zero or peak at 5 volts . if so you just found the "dead spot" in the sensor which is more than likely where you usually "cruise" at. the resistor circuit is in contact most often here and is the most likely position to wear out.

hope that helps a little but it seems like you got a handle on it by changing the setup. i would just prefer to verify the fix so you dont end up in limp mode when your in a hurry or some hot chick tells you to follow her to her house, then bam your stuck in the intersection in limp mode with your flashers on waiting for "AAA".

[edgy]

the sensor giving me problems is the Accelerator Pedal Position sensor in the picture above ... there are 4 wires leading to it... i do not know of a way to test it the throttle pedal/cable only moves it in the last 20-30% of its travel... the DBW motor controls the 1st 70% of movement....


BUT... i just found a MASSIVE vacuum leak!!


one of the literally 1 year old only vacuum lines i use to run the vacuum signal to the LMS I-manage & the Cooling mist unit is TOTALLY cracked & split

i have suddenly been getting the 1171-1174 "lean mixture" codes... so i now know what is directly causing that.... even tho that code coming up is fairly new and recent & for some reason does not ALWAY come up immediately...??


BUT.. does any one here think that this massive Vacuum leak right after the TB could also be a contributor/cause for the Accel. Pedal Position sensor giving me shit...?

maybe the ECU is trying to make tiny adjustments to the throttle with the stepper motor for the DBW... & between the signals the O2 sensors are sending & the leak,...the ecu couldn't manage the problem so after a while it trips the code...?




PRAY for me this is a BIG part if not THE main part of the problem...

i am replacing ALL the fooking rubber Vacuum lines with silicone immediately.

and DO NOT USE stainless braided rubber vacuum hoses...!!!! i bought a bunch of this stuff brand new last year to finish the motor off nicely & that shit evidently SUXXX ass...

[edgy]

Pffuhk me!!!!


ok i cant believe it took 10 weeks to figurethis out.... but since my Vacuum hoses were all less than a year old... & I don't drive the car THAT much.... Plus since I checked them all, & cut off any split ends & used the clean solid part an inch up i thought all was good..........but 4-5 inches up the hose & under the sleeve....it was cracked all to shit.... & eventually the cracks split thru & the hose leaked like a siv!!

..freekin hose looked like it had been sitting in the sunlight in vegas for a year....


so I swapped out ALL rubber vacuum lines for silicone stuff I've had for a while..
& fired it up...


Freekin' car fired up perfectly & settled into a steady Idle...

after 2 min it was solid at .72v on the TPS voltage & rpms smooth at 750-800RPM

... no missing... no hunting....no erratic AF ratio readings

No APP sensor circuit failures... NO CE LIGHTS!!!


the car drives BITCHEN again





BOOOOMUFUGGINYAAAAA!!!!!!!!!!!

& My Exhaust has cleaned up DRAMATICALLY...it was a STINKY bitch while this problem was happening..... I was worried about people noticing....
....now it is obvious there are no cats... but it is MUCH cleaner & less obnoxious... or just less noxious....



sometimes, it is the simplest shit....