Stroock639

any help would be appreciated please

car started from cold just fine and ran normally (it was a cold day about 20 degrees f) for a good 15 minutes, when i then parked it for about 25. after i came back out and started it again i got a check engine light and check vsc warning, accompanied by a loss of accelerator pedal function and a high idle. in neutral it was idling at about 1500 rpm, and when in drive the car is accelerating on its own, almost like the pedal is being pressed slightly. it was also shifting out of first with a jerk and the other shifts aren't great either.

the only way to get the car to move was by pressing the pedal all the way down until you can feel the cable manually operating the throttle plate. i plugged my obd ii wifi adaptor in and got code P1121, not P1121 and P1120 like others have posted. also, i'm at about 132,000 miles.

weirdly there seems to be very little information on the accelerator pedal position sensor, any searches for it will result in the throttle position sensor which isn't the same thing. is it even possible to purchase the pedal sensor?

edit: ok so even though toyota calls it the accelerator pedal position sensor they sell it as the "lever assy throttle" part 22060-50011, list price is $402, although it's a much more reasonable $280 here

aptoslexus

isfdude

iTrader: (11)

Check the throttle position sensor. It's located on the throttlebody.

Stroock639

that's definitely a lot of info but i have code P1121, which is "Accelerator Pedal Position Sensor Range/Performance Problem"

yes you did...

aptoslexus

I posted the P1121 code at the end. It refers you to the P1120 diagnostic.

djamps

Same thing happened to my friend's 2000 tundra intermittently. New sensor is in the $2xx range and took about 15 minutes to install onto the TB.

isfdude

iTrader: (11)

I believe for The years posted on the form you have the throttle position sensor installed into the throttle body as you should have a pull cable throttle. The breakdown shown in the reply is for a electric lever designed pedal which means you would have a motorized throttlebody but those came out in the later years on the LS Lexus vehicles.

Stroock639

ok so i had my boi bring his multimeter down and we measured the resistance between the two points as shown, and the figure was about 2.54 or something, which is right about in the middle of the range. the car started and ran fine, and even after sitting for like 20 mins after warming up which is when the problem first started, it didn't this time.

i ordered the new sensor already which is honestly probably what fixed it, but i'll hold onto it anyway in case it happens again. it should also be noted that it's about 30℉ now and it first happened when it was about 19℉, so i'll definitely be on the lookout for that.

these damn cars, they start working fine again when they know they're trying to be diagnosed...

isfdude

iTrader: (11)

Lol just like most cars when you bring them to the dealer and it's perfectly fine. Then when you leav the problem comes back.

Stroock639

so my plan was to leave the "v bank cover" off so in case the APPS acted up again i wouldn't have to take the cover off again, and of course the thing kept working perfectly... so to try to get something to happen i put the cover back on, and sure enough like clockwork the first drive i take with the cover back on it starts acting up. this time there was no code, check engine light, or limp mode... but with the car warmed up it was idling at like 1400rpm, almost like it was applying some throttle even though i wasn't. it was the same circumstances too, car started and ran fine initially, but after warming up and then sitting for like 20 mins when i went shopping it started being weird on the drive back.

i checked the sensor to see if somehow the cable was maybe pulling on it, but the sensor was all the way forward in the resting idle position. imma just go ahead and put the new part in, and maybe even see if lexus will pay for the part seeing as it is covered under the toyota economic loss settlement. i hate cars.

valex

So, was it the Trottle Body Lever Sensor that cured your P1121?

WaveRunner

I believe I am experiencing this problem right now. I have a 1998 LS400 with about 140k miles. Car was idling then all of a sudden check engine and check VSC message appeared. RPM was acting weird and when shifting into and out of reverse the car jolted. The accelerator feels like it wouldn't move the car. OBD II scanner reads P1121 which is pedal position sensor. Turned the car off and back and the errors appeared but car drove fine. I will try to clear the codes but would like to preemtively solve this issue to prevent this happening on a busy road or highway. Has replacing this sensor fixed this problem for most?

Stroock639

i never replaced the sensor, it's held in by 3 phillips head screws and they seemed on the verge of stripping so i just left it alone for the time. so far *knocking on wood as i type this* it's been ok, my main advice would be make sure the throttle cable isn't too tight and make sure your battery and electrical system are working. voltage getting too low can wreak all sorts of havoc to a car.

WaveRunner

Today I had no problems. The check engine light was gone. I read others have seen this and it returned unexpectedly weeks or even months later. I went ahead and bought an OEM APPS or Throttle Body Lever Sensor as Toyota calls it.

Part number:

• 22060-50011 1998+ LS400 THROTTLE BODY LEVER SENSOR aka ACCELERATOR PEDAL POSITION SENSOR

I'd like to preemptively take care of this issue and hopefully never see it again. Paid $158 from a reputable seller on Ebay. They are apparently sold often based on the purchase history on the seller's page. I also read on these forums that many people mistake the symptoms I described in my initial post for the throttle position sensor (TPS) going bad which is a different sensor altogether found on the throttle body. Apparently Land Cruiser/LX470 experience this issue as do some GS both V8 and 6-cylinder models. I'll have my mechanic install it. I don't care how easy it is, I don't want to strip anything.

Yamae

This is an old thread but have you resolved the problem, Stroock639?

I recently had this problem and the resoldering 4 pins of the APPS seemed fix the problem. I couldn't see those 4 soldering points but I dare tried to heat up pins trying to melt the soldered points where the internal board is connected to pins. It seemed to work well to resolder since the problem can't be duplicated any more even stressed badly. Without buying and spending big $, I think I was able to fix the problem just doing the soldering.

The photo below is an APPS for a GS300/IS300 and it's not the same with what for a 1UZ-FE VVT-i engine's but the structure is similar.



This is about a GS300/IS300 and you can watch the full video at, The photo above was picked up and captured by me at 2:37.

This is just my experience and it's just another board but soldering cracks often happen at the edge of connectors when aged due to the thermal expansion's differences like this below. The material for the connector's plastic expands more than the board material, we need to know.