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Discussion Starter · #1 ·
Hello All,
I started to encounter a new issue with my daily driver stock 01 IS300 which progressively got worse after changing throttle position sensor (TPS). At first turning off the engine and restarting would allow me to drive at highway speed but CEL and TracOff lights would not go away. Received code 1120 at local auto zone. They suggested I change the throttle position sensor (TPS).

Based on the code, changed the TPS (Lexus P/N 89452-30150) but nothing changed. Went to local O'reileys and got same code (1120) with the new TPS but was able to drive at highway speed. Came home removed and reinstalled the TPS but the lights stayed on so I called it a day. The next day starting out from home both CEL and TracOff lights went off. Went for test drive and problems became worse, CEL and TracOff came back and added no acceleration/power with only crawling speed available. Restarting several times didn't help so decided to wait few minutes restarted got highway speed back but with CEL and TracOff lights on. Came back home. Following day same results, both lights gone, started from home and immediately the lights came back on.

Now, next options are to change the accelerator pedal sensor (APPS) (Lexus P/N: 22060-46010) and/or the Throttle Control Motor (TCP) (Lexus P/N: 89672-30020).
I really don't want to start throwing parts without diagnosing the problem and it will fast become expensive; the APPS alone is $300-$500 and so is the TCP which I am trying to avoid spending.

I have a newer (changed a little over a year ago) mass airflow sensor (MAF) and it is clean but also don't think it is a MAF issue either.
 

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Discussion Starter · #3 ·
That code is not the TPS. You must change the APP sensor if the connection is good.

Thank you 01 SolarYellow for the quick feedback. I just realized that I had a typo with the error code in the subject line and also in the post. The error code should be P1121 and not P1120. I am not sure how to correct them.

What is your opinion regarding P1121 with rest of the issues being the same?
 

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The 1120/1121 is the APP. Replace it. It is the one that the accelerator cable attaches to. Or roll the dice with a used whole throttle body.
 

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any update? im having this issue right now P1121, and i was gonna resolder but went to a used throttlebody, Any update on yours? i wish i can do mine.
 

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Discussion Starter · #7 ·
any update? im having this issue right now P1121, and i was gonna resolder but went to a used throttlebody, Any update on yours? i wish i can do mine.
I have not yet been able to complete the job as I am still awaiting for the parts that I ordered from Lexus.

In a new development, while I was removing the throttle body, I found out that the Lexus tech/s who had previously worked on my car at some point in the past had "glued" yes glued the cracked throttle control motor connectors instead of replacing them. So I now need to replace both the motor connectors.
I also may have to replace the APPS connector because its clip broke off when I was disconnecting it.

In the meantime, I have re-soldered the joints in the APPS but I am not sure if it will work. I will only know once I put everything together after I receive the parts from Lexus.

Try re-soldering the APPS joints, if it works then you can save the money. Either way, keep us posted.
 

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I have not yet been able to complete the job as I am still awaiting for the parts that I ordered from Lexus.

In a new development, while I was removing the throttle body, I found out that the Lexus tech/s who had previously worked on my car at some point in the past had "glued" yes glued the cracked throttle control motor connectors instead of replacing them. So I now need to replace both the motor connectors.
I also may have to replace the APPS connector because its clip broke off when I was disconnecting it.

In the meantime, I have re-soldered the joints in the APPS but I am not sure if it will work. I will only know once I put everything together after I receive the parts from Lexus.

Try re-soldering the APPS joints, if it works then you can save the money. Either way, keep us posted.
I have not yet been able to complete the job as I am still awaiting for the parts that I ordered from Lexus.

In a new development, while I was removing the throttle body, I found out that the Lexus tech/s who had previously worked on my car at some point in the past had "glued" yes glued the cracked throttle control motor connectors instead of replacing them. So I now need to replace both the motor connectors.
I also may have to replace the APPS connector because its clip broke off when I was disconnecting it.

In the meantime, I have re-soldered the joints in the APPS but I am not sure if it will work. I will only know once I put everything together after I receive the parts from Lexus.

Try re-soldering the APPS joints, if it works then you can save the money. Either way, keep us posted.
Hello little update on my P1121 situation, Cel plus blinking trac and unresponsive throttle. So i just did replace the whole throttle body with a used one. And my car ran perfectly fine (40miles). And upon checking i saw mine that all of the plugs for throttlebody is a bit crusty and u need to help push the wires inside check yours too i wish this things helps u out
137868
 
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