IS - 1st Gen (2001-2005) Discussion about the IS models up to the 2005 model

Help Me, Code: P0120/P0121...

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Old 09-28-10, 02:53 PM
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shahir18
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Default Help Me, Code: P0120/P0121...

I got a code read done from toyota, thinking it was the sensor failure... I changed the sensor, but i'm still having the same check engine/track off light flashing. My accelerator still feels hard and i have to press it in at least half way before it gives gas! I have even tried cleaning my maf sensor with CRC MAF cleaner... but still all the problems are still there.

HELP ME, before i go out and have to spend more money... thanks!
Old 09-28-10, 03:30 PM
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anotherLS
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TPS sensor went bad...Throttle Positioning Sensor, its right next to ur throttle body
Old 09-28-10, 03:34 PM
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shahir18
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Originally Posted by anotherLS
TPS sensor went bad...Throttle Positioning Sensor, its right next to ur throttle body
Like stated in the original post - I have replaced it with a New OEM Toyota TPS, problem is still there...
Old 09-28-10, 08:46 PM
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03LexIS300
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Originally Posted by "that boy"
Like stated in the original post - I have replaced it with a New OEM Toyota TPS, problem is still there...
have you tried throttle body cleaner? also, theres a rubber piece that connects the throttle body to the intake manifold are there any cracks or visible splits in that?
Old 10-01-10, 02:20 PM
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shahir18
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Originally Posted by 03LexIS300
have you tried throttle body cleaner? also, theres a rubber piece that connects the throttle body to the intake manifold are there any cracks or visible splits in that?
I have cleaned my throttle body, but i dont have a second person to have them start the car and have me spray it while its running.... No visible splits or anything
Old 10-01-10, 07:29 PM
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03LexIS300
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did you check your intake manifold for any vacuum leaks?
Old 10-02-10, 08:39 PM
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nguminh
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Originally Posted by 03LexIS300
did you check your intake manifold for any vacuum leaks?
This^ or your gas cap isn't on tight and it's not holding in pressure doubt it though.
Old 10-06-10, 04:12 PM
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i had this problem for a LONG TIME ... and it ended up being a vacuum leak after the MAF sensor..... you need to check EVERYTHING ... all hoses that attach to the intake manifold all intake manifold bolts and gaskets.... literally everything connected to the intake mani after the maf/throttle body....


good luck bro...
Old 10-07-10, 10:04 AM
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shahir18
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Originally Posted by edgy
i had this problem for a LONG TIME ... and it ended up being a vacuum leak after the MAF sensor..... you need to check EVERYTHING ... all hoses that attach to the intake manifold all intake manifold bolts and gaskets.... literally everything connected to the intake mani after the maf/throttle body....


good luck bro...
thank you sir, i will look into it right now...
Old 01-24-11, 12:55 AM
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DRACO A5OG
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I attempted to clean out my ICV without removing it. TB was removed from the intake but I just ran carb cleaner thru the ICV until it came out clear.

I also replaced the Fuel Pressure Regulator, it was leaking.

Car starts right up and runs allot better, it will not trip my previous misfires on 2, 4 & 6 but now I have the dreaded P0120. I tapped at the TPS, it hesitated for a second then got a reading of P0121 as well.

While driving at nominal speed, when I want to accelerate, she will not kick down when I am on the freeway, the RPMS will just drop to 2000-2200, most likely related to the TPS.

I am planning on removing the ICV and thoroughly cleaning it and if it does not correct the issue then I will check the resistance on the TPS terminals using this method I found for the LS400 guys
http://www.lexls.com/tutorials/EFI/tps.html.

Yes, I will check for vacuum leaks.

Last edited by DRACO A5OG; 01-24-11 at 01:08 AM.
Old 01-26-11, 06:14 PM
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DRACO A5OG
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Default Check Mecahnical 1st prior to swapping components

Update:

More details, I also changed the valve cover gaskets, OMG what a nightmare.

Anyways, my friend apparently took off the accelerator cable and transmission cable off of the throttle body and when he put them back on, they were too tight.

I adjusted both cables to spec.

Voila, P0120 code did not re-appear and she idled normally.

She also "kicked down" when I stomped on the pedal at nominal speed.

Thank goodness I checked the simple stuff first before dropping $99 on a new TPS.

Side note my friend found the Fuel Pressure Regulator was bad so it was replaced and I got rid of the Mis-Fire issues on 2,4,6.

Jim
Old 01-28-11, 02:39 AM
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mlcoolj
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good to know you solved the problem!
Old 01-30-11, 07:07 PM
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Pat5HKU19
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The IS tends to do this when you install an aftermarket intake. If it comes up again disconnect your battery to reset the ecu ... it will go away for a while and might come back on. Before turning off my car ill let it idle for about it a minute then shut the engine off. The better you maintain the intake(like stated above) the less chance you have of the light coming back on. Try to put a heat shield on if you dont have one.
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