OBD-II Generic Error Code P0418: How to Fix It

Q: Can I drive with a P0418 code?

Yes, but it may cause your vehicle to fail an emissions test. It typically doesn't affect drivability, but the check engine light will be on.

Q: How much does it cost to fix error code P0418?

Cost varies: a fuse is under $10, a relay around $20, a pump from $100-$400, and labor from $100-$200. DIY can save on labor.

Q: What happens if the secondary air injection pump fails?

The pump failure itself won't damage the engine, but the system is part of emissions control. Your check engine light will stay on, and you may fail an emissions test.

Q: Why does P0418 appear only in cold weather?

The secondary air injection system only operates during cold starts to reduce hydrocarbon emissions. If there is an intermittent electrical issue, it may only trigger when the system activates.

Q: Can a vacuum leak cause P0418?

No, P0418 is specifically an electrical circuit fault. However, other secondary air injection codes (e.g., P0410) can be caused by vacuum leaks or blockages.

Abstract

Error code P0418 means your car's secondary air injection pump A circuit is malfunctioning. The secondary air injection system pumps fresh air into the exhaust to reduce emissions on cold starts. This code indicates an electrical issue (open or short circuit) in the pump relay, wiring, or the pump itself.