What does code P0411 mean?

Q: What does code P0411 mean?

Secondary Air Injection System Incorrect Flow. P0411 means the engine computer has commanded the secondary air injection (AIR) system to pump fresh air into the exhaust, but the oxygen sensors did not see the expected change in exhaust oxygen content. The computer detects incorrect flow by comparing oxygen sensor readings before and after the air pump runs, and it sets this code when the response is too small or missing.

DTC codes / P04xx · Auxiliary emission controls / P0411

P0411Secondary Air Injection System Incorrect Flow

P0411 means the engine computer has commanded the secondary air injection (AIR) system to pump fresh air into the exhaust, but the oxygen sensors did not see the expected change in exhaust oxygen content. The computer detects incorrect flow by comparing oxygen sensor readings before and after the air pump runs, and it sets this code when the response is too small or missing.

SystemPowertrain

Code typeGeneric (all makes)

SeverityLow

Fix difficultyIntermediate

AreaAuxiliary emission controls

Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.