Chrysler check engine codes for vehicles from the late 1990s on start with the letter P followed by four digits. Chrysler vehicles prior to the late 1990s produce two-digit error codes.
When a vehicle's on-board diagnostic system senses a malfunction, it sends an error message to the driver by illuminating the Check Engine light. Specialized computer readers plug into the car's system and read the error code. Several OBD readers and scanners are available. The error code assists mechanics in diagnosing what is wrong with the car and how to fix the problem.
The Clean Air Act Amendments of 1990 requires all vehicles produced from 1996 on have built in OBD systems. The OBD system not only signals engine trouble, it also helps states meet national air quality standards by monitoring vehicle emissions.