To find out the specific cause, you should:
* Consult your owner's manual: This is the best resource for understanding what the warning lights in your specific PT Cruiser model mean.
* Look for other illuminated warning lights: Other lights (like the check engine light) will help narrow down the possible problems.
* Have your vehicle diagnosed: Take your PT Cruiser to a mechanic or auto parts store that can read diagnostic trouble codes (DTCs) from your car's computer. This will pinpoint the exact issue.
Ignoring the exclamation mark could lead to further damage or unsafe driving conditions.