Operating a vehicle with an exhaust system that has been modified, gutted, or altered to amplify noise beyond the stock configuration or California emissions standards.
This guide is for general educational purposes only and does not constitute legal advice. TicketClear is a self-help document preparation service — we are not attorneys and do not represent clients. Review all prepared documents carefully before submitting. Fine amounts are estimates and vary by county and surcharge schedule.
CVC 27150(b) specifically prohibits muffler cutouts, bypasses, and similar devices that allow exhaust to bypass the muffler. This targets intentional modifications, not simple defects.
No DMV points, $25–$200 fine, usually correctable. Remove the bypass device and restore the factory exhaust path.
No DMV points — no insurance impact.
No person shall modify the exhaust system of a motor vehicle in a manner which will amplify or increase the noise emitted by the motor of the vehicle above the level allowed.
Performance car with electronic exhaust valve that bypasses muffler.
Must disable or remove bypass; restore muffled exhaust.
These are the defense arguments that appear most often in successful Trial by Written Declarations for this violation.
No bypass device installed
Have a mechanic inspect and document the exhaust system.
Device was not in use
Some electronic valves default closed — document if bypass was not occurring.
⚠️ What NOT to Do
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Generally no — if they can route exhaust around the muffler, even closed-position valves may be cited.
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This guide is for general educational purposes only and does not constitute legal advice. TicketClear is a self-help document preparation service — we are not attorneys and do not represent clients. Review all prepared documents carefully before submitting. Fine amounts are estimates and vary by county and surcharge schedule.
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