Can a Car with Check Engine Light Pass Inspection?: 1 Minute to Understand Inspection Requirements

Whether a car with a check engine light can pass inspection largely depends on your local regulations, but in most regions of the United States, a vehicle will not pass a state inspection if the check engine light is illuminated. The check engine light, officially known as the "Malfunction Indicator Lamp" (MIL), signals that the car’s engine control unit has detected an emissions, engine, or other system fault. Inspections, especially those focused on emissions, require the onboard diagnostic system (OBD-II) to report no active faults. During the inspection, technicians connect to your vehicle’s OBD-II port to check for trouble codes, and if any codes are present—typically indicated by a lit check engine light—the vehicle fails the inspection.

There are some exceptions for older vehicles (often those older than 1996), as they might not be equipped with modern OBD systems, but this too varies by state. In certain cases, temporary waivers may be provided for minor issues or if you've already spent a significant amount of money attempting to fix the problem. Nonetheless, it’s always safer and more responsible to diagnose and address the root cause of a check engine light before attempting state inspection.

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Tips 1:

If your check engine light comes on just before inspection, don’t simply reset it—most inspection computers can tell if the system was recently cleared and will fail the car if enough drive cycles haven’t passed. Instead, have the issue properly diagnosed and repaired to prevent further complications (and added repair costs).

FAQ

Q: Can disconnecting the battery turn off the check engine light for inspection?

A: While disconnecting the battery can temporarily turn off the light, it will also reset the car’s onboard computer. This means the system will lack the required “readiness monitors” and will likely cause your vehicle to fail until it completes several normal driving cycles.

Q: Will a minor issue, such as a loose gas cap, cause me to fail the inspection?

A: Yes, even a minor issue like a loose or faulty gas cap can trigger the check engine light and cause your car to fail emissions inspection until it’s resolved and the system has reset.

Q: Are there any states where a car might pass with an illuminated check engine light?

A: Some jurisdictions may offer limited waivers based on age of vehicle or demonstrated hardship, but most states require the light to be off and all emissions systems to be functioning correctly.

Q: What steps should I take if my check engine light is on before an inspection?

A: Start by reading the diagnostic code (at a parts store or mechanic), address the issue, and then drive your car several cycles so the on-board computer can verify the repair before you go for inspection.

Q: Does a check engine light always signal a serious problem?

A: Not always—sometimes it’s a minor issue like a loose gas cap, but it can also indicate more significant emissions or engine problems. It’s best to have it checked promptly for both inspection and safety reasons.