P0121 after replacing TPS Sensor & still on after putting OEM TPS Sensor back in
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Hello,
I need some help figuring out an issue. My 96 Lexus ES300 suddenly started have issues staying on and would idle roughly. No check engine light was triggered. I tried replacing the Camshaft & Crankshaft Position Sensors & TPS sensor and still no change. I eventually noticed that the Camshaft position sensor connector was damaged and replaced it. My car seemed to be back to normal so I though it was fixed. After driving about 15-20 miles the check engine light came on and I scanned code P0121 (Throttle / Pedal Position Sensor / Switch 'A' Circuit Range / Performance). This was the first time I received this code. I cleared the code, unplugged the battery for over 30 minutes, but the code kept returning after short test drives. I put back in the original throttle position sensor, cleared the code, unplugged the battery for several hours, but the code still returns. I could not find any deadspots while using multimeter and it tests approximately 16% at idle and about 80% WOT.
How long has your 1996 Lexus ES300 had this problem?
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Sounds like you may have some excessive carbon build-up around the throttle plate.
You can remove the intake boot from the filter housing & the throttle body, then use some carb cleaner or throttle body cleaner a rag to clean it out.
Then can hold the throttle open by having someone depress the accelerator with the ignition on or you can gently push & hold the throttle plate open with your hand.
Once you've removed the carbon, re-assemble the intake, and start the vehicle a couple of times to clear out any residual cleaner.
Then clear the codes & re-test.
Let us know how it goes!
