How to Install the Wrangler PCM

The Wrangler powertrain control module, or PCM, is located in the engine compartment. It has three 32-pin connectors. The PCM reads information from several sensors and components outputs the information to the fuel injection, ASD relay and other components for optimal vehicle operation. It regulates the ignition timing, air-fuel ratio, emission control devices, charging system, speed control and the air conditioning clutch engagement and idle speed.

Instructions

1

Disconnect the negative battery cable using the appropriate wrench. Set it aside, ensuring that it does not touch metal. Ground yourself by touching metal. Even a small spark caused by static from your body can damage the PCM.

2

Unsnap the plastic cover that protects the wiring harness connectors and pull it off the connectors. Pull the three 32-pin connectors off the PCM. Make sure you pull them straight off so that you do not bend the pins.

3

Remove the three PCM mounting bolts using the appropriate socket. Remove the PCM from the engine compartment.

4

Install the new PCM and tighten the mounting bolts to 35 inch-pounds of torque. Plug in the three 32-pin connectors. Reinstall the plastic protective cover over the connectors. Reattach the negative battery cable.

5

Take the Jeep to the dealership to have them program the new PCM with the VIN and the vehicle's original mileage. If you do not reprogram the PCM it will set a code and turn the check engine light on.