Troubleshooting a vehicle has become much easier since the advent of the On-Board Diagnostic system. The OBD system monitors numerous vehicle sensors and reports any faults to the vehicle's computer. When a fault is detected, the problem is recorded as a trouble code in the computer and the Malfunction Indicator Light is illuminated. The Malfunction Indicator Light, also known as the "check engine light," lets you know that a problem has occurred and a trouble code has been stored to help identify the problem.
Sit in the driver's seat of your PT Cruiser and insert the key into the ignition switch.
Turn the key forward to the run position, back to the accessory position, forward to run, back to accessory, then forward to run; all key turns should be completed in four to five seconds.
Make note of any codes that are displayed in the odometer window.
Remove the key once all codes have been recorded.
Cross-reference the displayed codes with the list provided on the PT Cruiser Forum website (see References).
