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Lexus IS300 car going in limp mode throwing engine, traction and VSC light on

4K views 23 replies 6 participants last post by  Azadvir 
#1 ·
When i drive car drives good suddenly anytime engine, trac, VSC light comes on and i lose accelaration cant drive tha car. When i let it cool down goes again good for half hour and same problem again.
please help i pull throttle body out but all seems fine. What could be the problem?
 
#5 ·
I dont know i put scan tool it says P1121 Accelerator position sensor range/ Performance problem. I changed TPS before puling the Throttle body out but didnt fix the issue.
now i got throttle body out of the car. Thinking if replacing it will fix the issue or that is not even the issue !
The APP sensor is the one the throttle cable attaches to. Replace it.
 
#8 ·
hey guys, i ordered APP sensor of ebay 130$ waited 2 weeks to arrive it arrived today i put it in my car and problem still there. Can someone suggest what else to check.
when i rotate the APP sensor with hands, flap inside throttle body only opens little little bit like quarted and now i got new APP snesor flap even opens less thn it does with original sensor.
i dont know if the sensor i bought new is good or not. So confuse please help
 
#10 ·
Yes the problem started happening after hitting speed bump hard u think it was never sensor faulty just any of the connector broken!
But scan tool showed P1121 code thats why i replaced that sensor. Can there be any connector under the car can cause this issue?
 
#11 ·
The sensor does go bad, it’s a know issue like you will see if you search. The solder inside the sensor circuit board cracks and that can cause the CEL to come on and off when the circuit opens as you drive. Eventually it will stay on. As for YOUR particular problem, if you keep getting the same code then you need to diagnose or take it to a shop. The connector has 4 wires to it; 2 signals, 5 VC and ground. Check that you have all that with ign on, double check all connectors and that you installed the new sensor correctly.
 
#12 ·
I checked all connectors nothing seems broken
Now the exact issue is
I started the car started as normal, pressed accelerator pedal it worked like normal but only for once and second time i press no acceleration, only when i go all the way to the floor little bit acceleration. Is this how it sounds if u seen this problem before?
Could it be electric motor that controls the flap! Does motor go bad as well over time and causing this issue or is it only that APP sensor
 
#16 ·
Hi,
Mh car in limp mode for last five weeks really struggling to fix it. So far replaced TPS and APP as well didn’t fix the issue.
Now when start the car its fine but as soon as press the accelerator pedal once, engine traction and vsc ligths come on and pedal only work when pressed about 80 %.
Checked wiring cant see any damage and connectors good as well. Now suspecting throttle control motor is faulty.
i have seen some posts about installing throttle lock behind APP sensor that removes purpose of motor.
would fix the issue and u can remove the motor as it will no use and would warnings signs will stay there?
please help
 
#17 ·
Hi,
Mh car in limp mode for last five weeks really struggling to fix it. So far replaced TPS and APP as well didn’t fix the issue.
Now when start the car its fine but as soon as press the accelerator pedal once, engine traction and vsc ligths come on and pedal only work when pressed about 80 %.
Checked wiring cant see any damage and connectors good as well. Now suspecting throttle control motor is faulty.
i have seen some posts about installing throttle lock behind APP sensor that removes purpose of motor.
would fix the issue and u can remove the motor as it will no use and would warnings signs will stay there?
please help
@persocon please help if u know or i hVe to replace throttle body assembly!
 
#19 ·
Fam, no one is gonna help you if you don’t help yourself. All the info you need is already here, but everyone needs everything spoon fed…
RM is the repair manual. Here’s the info you couldn’t bother to search for. Also stop double posting threads for this same problem. If you’re not capable of doing these checks stop wasting time and take it to a professional tech.
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#21 ·
Fam, no one is gonna help you if you don’t help yourself. All the info you need is already here, but everyone needs everything spoon fed…
RM is the repair manual. Here’s the info you couldn’t bother to search for. Also stop double posting threads for this same problem. If you’re not capable of doing these checks stop wasting time and take it to a professional tech.
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Thank tou and i apologise. I did try to search but nothing came up as i didnt know what i was searching fir thank you
 
#22 ·
So do you have any codes? And was the TPS sensor calibrated correctly when you installed it? Was it an oem sensor?

I recently had issues where my throttle pedal would work sometimes but without any codes. Turns out, my throttle cable was just on too tight. There needs to be a little slack so the APP sensor could go back to its original position when the gas pedal is released.
 
#23 · (Edited by Moderator)
I'm here with the same issue,got a replacement engine from gs 300 into my IS 300 and seems the engine of gs pretty faster a lil bit than IS 300 2jz stock. Now I got acceleration ish code. For that reason,it gulps fuel. Thinking about buying another throttle body assembly complete. Lexus is just too se sensitive. My car doesnt rev pass 2900rpm,tho the speedometer raises up to 1140kph,but my rpm doesnt exceed 2900rpm.

Same thing with mine. Doesn't exceed 2900rpm. Code says throttle acceleration range problem. I might get another replacement for throttle mouth(assembly)
 
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