The diagnostic codes on a Chrysler 300-series vehicle are stored in the internal memory of the power train control module (PCM). In order to access and reset these codes, an automotive scan tool is required to communicate with the vehicle's computer. Once a scan tool is connected to the vehicle's diagnostic data port, the codes can be read, cleared and reset. The codes cannot be reset by disconnecting the vehicle's battery or unplugging any of the electrical connectors.
Place the Chrysler's transmission in park and shut down the engine. Set the parking brake and turn the ignition to the "ON" or "ACC" position. Do not start the engine.
Plug a scan tool's data cable into the Chrysler's diagnostic data port. This port is located underneath the dashboard on the driver's side, just above the pedal area.
Power on the scan tool and follow the on-screen instructions to enter the vehicle's specific engine and drivetrain information.
Choose "PCM" from the scan tool's main menu. Select "codes," then choose "clear all current and stored codes." Wait for the scan tool's screen to confirm that the codes have been cleared.
Start the engine and verify that the service engine soon (SES) light is not illuminated. The diagnostic codes are now reset.
Automotive scan tools are small computerised units that connect to passenger vehicles in order to communicate with their on-board computers. They are available from auto parts stores and automotive tool retailers.