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jdloaner 07-08-2012 04:00 PM

TPS Sensor/P0121
So my Jeep (2000 Limited 4.7) started bouncing idle a ton last week, even while stopped would rev to 1300 for a sec. Then yesterday on the way to beach the shifting was clearly having problems. By the time I got over there while slowing down ~10-15 I noticed it was confused on when to downshift into first(maybe second) and almost stalling. Then literally as I was parking the check engine light came on. This morning I grabbed the code (p0121) and swapped out the TPS. Since then shifting seems perfect and idle is steady at 650-ish, no bouncing at all.

Just wanted to thank everyone as I used your suggestions, information, and pictures to get it done. Much appreciated!

Had a quick question however, do I need to disconnect the negative terminal and bleed out the power with the brake pedal trick to do some sort of reset with the new TPS, or is it good to go? Shifting seems completely normal but possible when coming to complete stop it looks to rev from about 800 up to 1000 on the downshift and then levels out and sits. This seems normal but just wanted to verify I did everything I needed to.

Again, thanks for all your help. This is my first post and I plan on continuing to help where I can.

hoffmanestates 07-08-2012 05:26 PM

that how u reset ecm on some cars. u disconnect the power leave ground on and press brake pedal few times

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jdloaner 07-09-2012 12:18 AM

Re: TPS Sensor/P0121
So do you think this is required in my case?

Trav1s 07-09-2012 12:41 AM

Re: TPS Sensor/P0121
I did it when I replaced the TPS on my WJ. It will help the computer learn faster.

2005JGC 07-17-2012 02:25 AM

Re: TPS Sensor/P0121
not required.

jdloaner 07-17-2012 07:50 PM

Re: TPS Sensor/P0121
Thanks for your help guys, working great.

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