Re: 99 cherokee P0121 code - New Member
Welcome to the garage,
The TPS sensor is easy to replace. It sits on the left side of the throttle body (seen from drivers position) and is the upper one. The lower one is the Idle Air Control stepper motor. Check the wiring first and clean the connector of the TPS, but most probably the TPS itself is the problem. Just one connector and two TorqX screws (20 or 25, donīt remember) and you have the TPS in your hand. Some prefer removing the air resonator box, but is not really necessary.
Is there any erratic idle problem or shift problems?