bossco416

I've looked over the forum and found little information on this code.
Seems to be some different opinions on the problem.

I have a 2000 Lexus GS300 that has had it's fair share of issues. The master brake cylinder has gone twice !

I just changed 3 O2 sensors in order to pass the E-TEST here in Ontario Canada.
You can't have your check engine light on to pass.

ANYWAY..................

3 O2 sensors changed last week, car was fine.
Then days later driving the car it felt like the car lost power 3 or so times. By the time I felt it, processed it and looked down all was fine on the dash. I was low on gas and thought I could be running out. That night driving home I again felt this loss of power, but again by the time I looked down all was fine. I thought it was odd, but I'm not much of a car guy.

That night going home my car did it again, however the CHECK ENGINE, VSC and VSC OFF light all game on. The car had no juice, pedal to the floor the car was crawling. I was two minutes from home, got the car home and parked it.

Several times during the day I would start the car, reverse and go forward. At one point the lights were off and I was able to take the car around the block. I called my mechanic asking if I could take the car to be scanned. When I went outside to start it it happened again.

He scanned it and it showed code P1120. He circuit sesor issue. He said he would need to look into this and gather more info. I drove the car home and it's been parked.

I'm in Toronto, Ontario Canada. I'm trying to debate if it is worth fixing or if I should cut my loss and junk the car. (even though the O2 sensors + labour ran me $540 a week ago)

Any ideas, is this part costly ? Easy fix ? Cause ? etc

Thanks all

paige

when was the last time the MAF and air filter were checked. When I had to replace my o2 for a CEL the car did not lose power or go into a limp mode. Just a CEL light that needed fix for inspection pass.

bossco416

I'm soooooooooo not a car guy.
I have no idea what MAF is.
If you could please explain (sorry).

As far as the air filter goes I honestly dont know. But I'll guess 2 years easily.

With respects to the O2 sensors I can verify the codes were present as the mechanic showed me.
He also had me pick up the parts and showed me the old ones.

This code, P1120 "accelorator pedal malfunction sensor circuit malfunction" is what it reads.

sw151143

I just made a new thread, I am having similar issues and can't figure this out. After much research the majority that I read with similar problems and this code, which I had also, said they changed the pedal position sensor and it fixed it. I changed mine and it cleared the code but I still have the same problem but no code anymore. I don't know what else to do.

bossco416

So you changed the circuit/sensor and the problem is still there, just no code ? WOW
What did the part cost you ? (I'm in Canada, I know it will be more, but I'd be interested to find out)

Sampak

The MAF or Mass Air Flow sensor is found in fuel injected cars (so basically anything sold today that runs on petroleum, unless it's using a mechanical means such as carburetor like in a lawn mower or moped LOL) senses the amount of air going into your engine so it can help the computer throw fuel into the mix in proper ratios blah blah blah, and is usually located just after the air filter box, inside the big air intake hose along the way into your engine intake manifold. If it gets dirty it plays havoc with the ECU (engine control unit/ engine computer, etc. etc) and causes all sorts of weird issues usually related to irregular engine performance.

While this doesn't usually happen on old cars from my experience, it is entirely possible if the air filter lets particles through or if dirt gets into the air intake and on its way coats the tiny sensor sticking its head out along the air stream.

I don't know the exact steps to cleaning a MAF sensor so I won't risk misguiding you, but you should be able to find instructions with a generic Google search. Basically involves blowing over it or wiping it down ever so gently as they are quite over-sensitive to abuse.

sw151143

Yes, so my issue is entirely different. It had that code and only that code. Bought the sensor for $256 and changed it. No more codes whatsoever, but still experiencing the same issue.

sw151143

Yeah really weird, I was so sure that was my problem. I am taking it to a Lexus dealer tomorrow so i will keep you posted.

bossco416

Thanks guys.
I look forward to the response.

@ sw151143

What was the part you purchased called ?
My mechanic said he has to look more into this problem.
I however want to call this place I've dealt with prior (used parts) and see if they have the part.
I'll also call Lexus here to see what they charge.

It was mentioned prior something about the air filter, locally they are available for $35.
Just not sure if its even worth doing now.

Think its time I say LATER LEXUS !

sw151143

The part I bought is called the pedal position sensor, it is what the throttle cable goes on to. Basically on the throttle body you have that sensor on the back, throttle position sensor on the front, and then the throttle motor on the front next to throttle position sensor.. and after much research the most common fix was pedal position sensor but in my case it did not fix... I am pretty sure my problem is somewhere in the throttle body but I am not ruling out catalytic converter... I know your frustration, I'm going through it now lol... But my thinking is that these are excellent cars just have to get passed this small issue that gives major headaches

bossco416

See the error I have says circuit, I wonder if I need something different from what you bought.

sw151143

Yeah see I don't know, I had the code P1120 accelerator pedal position sensor circuit malfunction... And when I changed the part the code went away and hasn't come back... I will drive it more tomorrow to see if it triggers the code again.. So unless it throws that code again then I believe I have more problems... We'll see....

bossco416

Called Lexus today, the only sell the entire assembly. $1247 + %13 sales tax here in Ontario.
Called the used parts guy that I used prior, entire assembly $275 (I'm sure cash talks with him).
I need to call the mechanic now and see what he says.

I think regardless I wanna just get rid of the car. I'll fix it, but I'll sell it.
It never rains.........it pores !

Car was in my fathers name, but I was the primary driver. My father recently passed away so we had to move the car into my name. Required some paperwork to be completed, $20, 02 sensor replacement (to pass the e-test) $540, then it will need a safety (about $100), and get the plates again ($200 apx). So now tack on this repair it's like HOLY ******. I can't win !

sw151143

Not sure if you seen on my update thread but my problem turned out to be the catalytic converter.. So as frustrated as I was and thoughts of selling it I'm so happy with it now! Love it... Although that part did clear the code I am not sure if the converter caused that to malfunction also, I guess I'll never know :-/