How much does it cost to repair control emissions when light comes on?

The cost to repair control emissions when the light comes on can vary widely, typically ranging from $100 to over $1,000 depending on the underlying issue. Common causes include faulty sensors, catalytic converter problems, or issues with the exhaust system. Diagnostic fees, parts, and labor can all contribute to the total cost. It's advisable to get a thorough diagnostic from a mechanic to identify the specific problem before estimating the repair costs.