Question

I have a 2001 Jeep Wrangler 4.0L and I'm getting the engine code p0121.

Question 1: I cannot run my code reader while the engine is running. I can only do this with the ign on engine off. Is this correct?

Question 2: This code refers to the TPS as well as the MAP sensor. which one should I change?

Answer 1

HI there

First, you can run the engine with the code reader connected, there isn't any problem with that at all.

Second, this code is for the throttle position sensor only, it has nothing to do with the map sensor. In most cases replacing the TPS will resolve the issue.

Answer 2

P0121 Jeep Code - Throttle Position Sensor 1 Performance
Read more: https://www.autocodes.com/p0121_jeep.html