RX - 2nd Gen (2004-2009) Discussion topics related to the 2004 -2009 RX330, RX350 and RX400H models

Help! Check Engine P2121 Code

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Old 05-11-16, 05:58 PM
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Ahsalloum
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Default Help! Check Engine P2121 Code

Need some help guys. I have a 2004 RX330 around 110k miles. My wife was driving home the other day and check engine light, VSC and Trac Off lights all came on and throttle power is very low. Can barely get RPM to 2000 or 3000 rpms. I googled the code (P2121) and it said to replace Accelerator Pedal Sensor (Gas pedal). I removed cleaned the throttle body and installed new pedal and still have lights on and won't get up to 3000 rpms. Any suggestions? How do I reset the lights? I have had both battery cables off for an hour and it won't clear the memory. Radio still has presets, but windows and memory seats have lost memory. Please help on what I should do next

Thanks

Last edited by Ahsalloum; 05-11-16 at 06:18 PM. Reason: Misspelling
Old 05-11-16, 07:34 PM
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numbafree
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How long was the battery unhooked? 15 minutes always works for me. I believe by depressing the brake pedal it completely discharges any electricity left in the system. Also, you can get a code reader for $20 and erase the code yourself.

You replaced the accelerator pedal sensor with an OEM part?

There are code readers for ABS and SRS:

Amazon.com: INNOVA 3150 Diagnostic Scan Tool/Code Reader with ABS/SRS for OBD2 Vehicles: Automotive Amazon.com: INNOVA 3150 Diagnostic Scan Tool/Code Reader with ABS/SRS for OBD2 Vehicles: Automotive

Also, here's a link for the TSBs for your model year, even though you are out of warranty, it's good info:

https://www.automd.com/tsb/lexus_m/r...2004_y/?page=3
Old 05-11-16, 08:14 PM
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Ahsalloum
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Yes, I left both cables disconnected for at least 45 mins and still didn't clear everything. Should I just be disconnecting the ground cable or both cables. I have heard both ways.

Do you think if I am able to clear the check engine light, the car will start to drive normal? At least until it reads an error again.

Yes, I replaced the pedal I bought from Lexus for $67. I cleaned the throttlend body the best I could and I unplugged the MAF sensor while car was on and the car cut off, so I am assuming the MAF is good.
Old 05-12-16, 02:54 AM
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Update; I left both battery cables disconnected last night and the check engine, VSC and Trac Off lights are still on. Can't seem to get them to clear. Everything finally seems to lose memory, so that should have done it, but no dice.

With putting in a new accelerator pedal sensor and cleaning out the throttle body, what else should I do with this error message?

I have also checked the gas cap numerous times.
Old 05-12-16, 07:49 AM
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numbafree
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You can either look up how to reset the VSC and Trac, or buy a scan tool and turn it off yourself.

I'll just leave this here for you:
https://www.clublexus.com/forums/rx-...rol-light.html
Old 05-12-16, 08:21 AM
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Ahsalloum
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Thanks Numbafree.

Does anyone know what else I need to do to get my car working? Changed the accelerator pedal sensor as the error suggests and still can't rev car past 2000 rpms
Old 05-12-16, 11:31 AM
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numbafree
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If you are still getting a CEL, then you still have a problem. Either the same CEL or a different one, you need to check the code.
Old 05-12-16, 04:14 PM
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Ahsalloum
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Originally Posted by numbafree
If you are still getting a CEL, then you still have a problem. Either the same CEL or a different one, you need to check the code.
Do you know what else it could be with that code?
Old 05-12-16, 06:54 PM
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numbafree
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Not sure if you did a search:

http://my.is/forums/f87/is300-code-p...d-help-447301/

http://cars-safety.com/lexus/es300/e...ne-cooling.htm

https://www.clublexus.com/forums/per...p-mode-23.html

post #336. might be your ECU. did you check the current CEL and is it still P2121? If you have a code reader, can you check pending codes? I wonder if it's throwing other codes than just the P2121.
Old 05-16-16, 02:19 PM
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I am now getting 2 more errors (P0123 and P2135). I have cleaned the throttle body as best as I could and changed the Accelerator Pedal Sensor (gas pedal) and still did not help.

Any idea what could be wrong?

I really don't want to take it to a shop because I will have to tow it. It won't go past 1500 rpms and won't go faster than 10 mphs. Really can use the help guys
Old 05-16-16, 05:03 PM
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AAA is $55 for a year, and a 5 mile tow, $100 for the plus membership and you get 100 mile towing distance, no affiliation.

I don't think anyone else is responding because:
1) they would just be looking up the code for you on the internet.

2) you have a unique issue.

P2135 is throttle position sensor (TPS)

P0123 is high output for TPS. which means the ground wire is loose or disconnected, or it's a bad sensor.

Another possibility listed for both the P2121 and the P0123 is you might have a bad ecu.

http://www.obd-codes.com/p2135

http://www.obd-codes.com/p2135

I would invest in an OEM service manual, before throwing parts at this. or punt to a mechanic.
Old 04-20-17, 09:30 PM
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My car has been acting the same way it's a gs300. Some day are better than others with it, like today. Today it wAs running completely fine , but yesterday horrible. My car reads code P2121 circuit "D". I was told to replace the TPS. Which I did but nothing changed. My uncle did it and we didn't realize you had to calibrate it to a certain thing. Any idea how to replace this right ? The car still drives, like I said some days better than others. When it is acting up it will just take forever to accelerate and the RPM goes up pretty high but my car feels like it's not going very far. If I turn my car off for a min and then restart it , it starts acting fine till the next time it wants to start acting up. When I start my car to warm it up the RPM is always at around 1200-1500 but slowly moves now to normal once the car is heated. Is this normal? After I replaced the TPS, I was told to replace the APPS. This was supposed to fix the problem... But still now luck. Any clue what's going on ?
Old 04-20-17, 09:38 PM
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My car has been acting the same way it's a gs300. Some day are better than others with it, like today. Today it wAs running completely fine , but yesterday horrible. My car reads code P2121 circuit "D". I was told to replace the TPS. Which I did but nothing changed. My uncle did it and we didn't realize you had to calibrate it to a certain thing. Any idea how to replace this right ? The car still drives, like I said some days better than others. When it is acting up it will just take forever to accelerate and the RPM goes up pretty high but my car feels like it's not going very far. If I turn my car off for a min and then restart it , it starts acting fine till the next time it wants to start acting up. When I start my car to warm it up the RPM is always at around 1200-1500 but slowly moves now to normal once the car is heated. Is this normal? After I replaced the TPS, I was told to replace the APPS. This was supposed to fix the problem... But still now luck. Any clue what's going on ?
Old 04-21-17, 07:12 AM
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Originally Posted by Mekenzie00
My car has been acting the same way it's a gs300. Some day are better than others with it, like today. Today it wAs running completely fine , but yesterday horrible. My car reads code P2121 circuit "D". I was told to replace the TPS. Which I did but nothing changed. My uncle did it and we didn't realize you had to calibrate it to a certain thing. Any idea how to replace this right ? The car still drives, like I said some days better than others. When it is acting up it will just take forever to accelerate and the RPM goes up pretty high but my car feels like it's not going very far. If I turn my car off for a min and then restart it , it starts acting fine till the next time it wants to start acting up. When I start my car to warm it up the RPM is always at around 1200-1500 but slowly moves now to normal once the car is heated. Is this normal? After I replaced the TPS, I was told to replace the APPS. This was supposed to fix the problem... But still now luck. Any clue what's going on ?
Try this: unplug your negative battery cable for at least 30 seconds. Reinstall it, start car and let it idle for five minutes, then go drive it. Use every gear, including reverse. See if that allows your ecu to recalibrate system. You'll need to reinitialise power functions such as windows. Consult manual for this, it's easy.
Old 04-21-17, 07:21 AM
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Originally Posted by BlackLexRX
Try this: unplug your negative battery cable for at least 30 seconds. Reinstall it, start car and let it idle for five minutes, then go drive it. Use every gear, including reverse. See if that allows your ecu to recalibrate system. You'll need to reinitialise power functions such as windows. Consult manual for this, it's easy.
. Thank you I will try this and let you know


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