How do you reset pcm in Jeep Grand Cherokee?

To reset the PCM (Powertrain Control Module) in a Jeep Grand Cherokee, disconnect the negative battery terminal and wait for about 15 minutes to allow any residual power to dissipate. Reconnect the terminal, and then start the vehicle. This process clears any temporary codes stored in the PCM. If you're looking to clear permanent codes or perform a more thorough reset, using a diagnostic scanner may be necessary.