Secondary air injection
P0411
Secondary Air Injection System Incorrect Flow Detected
The pump that blows fresh air into the exhaust for a minute after a cold start isn't working as expected.
Fine to drive
Can I keep driving? Yes, in most cases. It won't hurt the car in the short term, but get it fixed. A check engine light that's already on can't warn you about a new problem. The car drives normally. It only affects cold-start emissions.
Common causes
- A failed air pump
- A stuck check valve or switching valve
- A blown fuse or relay
- A cracked hose
Listed roughly from most to least likely. The same code can have different causes on different cars.
What to do
- Listen for the pump running (a whirr) just after a cold start.
- Check its fuse and relay.
- Have the valves and hoses checked.
General guidance. Your owner's manual wins. If a red warning light is on or the car drives differently, stop safely and get help.
Related codes
Track this automatically in Tagwell Auto
Tagwell Auto keeps your car's service dates and mileage, so when a code shows up you know what was done last. With a Bluetooth reader for the car's diagnostic port (called OBD-II), the phone app can read the code itself.