P0121 code and fast idle

[SAVTJ]

Looking for guidance before I do anything. I was driving back to my house and noticed I got a CEL. I threw a scanner on it and got P0121. I pulled the negative battery terminal and reconnected it and went for a drive. I didn't get a check engine light, but the engine was idling faster than normal. After stopping to get some gas, the check engine light came back on with P0121. I thought that the symptoms of a bad TPS was rough or slow idle, not fast idle. Should I go ahead and replace the TPS?

 

[Mike Z]

Looking for guidance before I do anything. I was driving back to my house and noticed I got a CEL. I threw a scanner on it and got P0121. I pulled the negative battery terminal and reconnected it and went for a drive. I didn't get a check engine light, but the engine was idling faster than normal. After stopping to get some gas, the check engine light came back on with P0121. I thought that the symptoms of a bad TPS was rough or slow idle, not fast idle. Should I go ahead and replace the TPS?

On my 2002, I experienced a higher than normal idle and the same P0121 code. I replaced my TPS with a Mopar sensor and that fixed the problem. I would recommend installing a Mopar TPS as TJ's can be sensitive to other non OEM parts.

 

[CharlesHS]

Before throwing parts at the problem; test the TPS using this procedure.

 

[SAVTJ]

While I appreciate the idea of testing it, it was easy enough to order the part and replace it. I was able to swap it out in about 5 minutes without having to remove the airbox or anything. Luckily I had a few different T20 to play with (socket and screwdriver) that made it an easy chore. Fired it up and the idle problem was fixed. Took it out for a 20 mile test drive and everything checked out. Sometimes shotgunning the part works!

 

[Mike Z]

While I appreciate the idea of testing it, it was easy enough to order the part and replace it. I was able to swap it out in about 5 minutes without having to remove the airbox or anything. Luckily I had a few different T20 to play with (socket and screwdriver) that made it an easy chore. Fired it up and the idle problem was fixed. Took it out for a 20 mile test drive and everything checked out. Sometimes shotgunning the part works!

Glad to hear that you got it figured out. Happiness