P0410: Secondary air injection system malfunction
The secondary air system, which blows fresh air into the exhaust for a short time after a cold start so the catalytic converter warms up faster, isn’t working as the engine computer expects.
Updated
What P0410 means
Right after a cold start, a petrol engine’s catalytic converter is still too cold to clean the exhaust well. On many petrol cars a secondary air pump then blows fresh air into the exhaust, so leftover fuel burns there and the converter heats up faster. The pump runs only for a short time after a cold start.
The engine computer checks the system with the oxygen sensor: with the pump running, it should see extra oxygen in the exhaust. If it doesn’t, it stores P0410 or P0411.
P0411 to P0418: air flow and valve circuits
P0411 means the air flow wasn’t what the engine computer expected, usually too little. P0412 to P0418 are faults in the electrical circuit of a switching valve or of the pump’s control. The advice is the same for each; their own meaning is shown below.
P0411: AIR System A Incorrect Flow Detected
The secondary air system doesn’t deliver the air flow the engine computer expects after a cold start, judged by the oxygen sensor.
Common causes: failed secondary air pump or its relay, faulty or stuck check (combination) valve, carbon-clogged air passages or hoses, blown fuse.
P0412: AIR System Switching Valve A Circuit
The engine computer has found a fault in the electrical circuit of a secondary air switching valve or of the air pump’s control. The secondary air system then can’t do its job after a cold start.
Common causes: faulty switching valve or pump relay, wiring or connector fault, blown fuse.
P0413: AIR System Switching Valve A Circuit Open
The engine computer has found a fault in the electrical circuit of a secondary air switching valve or of the air pump’s control. The secondary air system then can’t do its job after a cold start.
Common causes: faulty switching valve or pump relay, wiring or connector fault, blown fuse.
P0414: AIR System Switching Valve A Circuit Shorted
The engine computer has found a fault in the electrical circuit of a secondary air switching valve or of the air pump’s control. The secondary air system then can’t do its job after a cold start.
Common causes: faulty switching valve or pump relay, wiring or connector fault, blown fuse.
P0415: AIR System Switching Valve B Circuit
The engine computer has found a fault in the electrical circuit of a secondary air switching valve or of the air pump’s control. The secondary air system then can’t do its job after a cold start.
Common causes: faulty switching valve or pump relay, wiring or connector fault, blown fuse.
P0416: AIR System Switching Valve B Circuit Open
The engine computer has found a fault in the electrical circuit of a secondary air switching valve or of the air pump’s control. The secondary air system then can’t do its job after a cold start.
Common causes: faulty switching valve or pump relay, wiring or connector fault, blown fuse.
P0417: AIR System Switching Valve B Circuit Shorted
The engine computer has found a fault in the electrical circuit of a secondary air switching valve or of the air pump’s control. The secondary air system then can’t do its job after a cold start.
Common causes: faulty switching valve or pump relay, wiring or connector fault, blown fuse.
P0418: AIR System Control A Circuit
The engine computer has found a fault in the electrical circuit of a secondary air switching valve or of the air pump’s control. The secondary air system then can’t do its job after a cold start.
Common causes: faulty switching valve or pump relay, wiring or connector fault, blown fuse.
Can I keep driving?
Check soon
Probably OK to drive short-term, but have it checked soon. Fuel use or emissions may be worse.
General guidance based on the code alone, not on the car’s actual condition. If in doubt, stop and ask a mechanic.
The car usually drives as before: the system only works for a short time after a cold start. A check valve that lets exhaust gas back towards the pump can damage it, so don’t leave it for long, and have it fixed before the next emissions inspection.
Symptoms
- Usually only the check engine light.
- A loud air pump after a cold start, or no sound from it at all.
- On some cars, a rough idle or hesitation just after a cold start.
Common causes
- Failed secondary air pump or its relay. Listen for the pump just after a cold start. If it doesn’t run, check its fuse and relay first.
- Faulty or stuck check (combination) valve. It keeps exhaust gas out of the pump. One that leaks lets hot gas back towards the pump and can damage it.
- Carbon-clogged air passages or hoses. The passages into the exhaust can carbon up, so the pump runs but too little air gets through.
- Blown fuse. Check it before replacing any parts.
Typical fixes
- Check the fuse and relay for the secondary air pump.
- Listen for the pump just after a cold start, and check its hoses for splits and loose ends.
- Have the check valve and the switching valve tested, and the air passages checked for carbon.
- Clear the code after the repair. Under emissions readiness, the Secondary air system self-test shows when the car has re-tested it.
Questions
Can I drive with P0410?
Probably for a short time, but have it checked soon: the app’s advice is that fuel use or emissions may be worse. The system only works after a cold start, so the car usually drives as before.
Why does my car blow air into the exhaust?
It helps the catalytic converter reach its working temperature faster after a cold start, when emissions are highest. Not every car has a secondary air system.