Secondary Air Injection System Malfunction
This code indicates a problem with the vehicle's secondary air injection system.
Heads up: this code wasn't in our hand-written library yet, so DiagCoach AI built this page on the fly. Double-check critical specs against service info before condemning parts.
What it means (plain English)
The secondary air injection system pumps extra air into the exhaust during startup to help reduce emissions. If it's not working, your engine might throw this code because it's not providing the extra air as needed.
What the computer is actually seeing
The engine control module (ECM) monitors the operation of the secondary air injection system, looking for expected airflow or pressure changes when the system is activated at cold start.
What a healthy reading looks like
Airflow should be around 10-20 CFM when the secondary air system operates; pressures should remain within the intake manifold vacuum specs, typically around -10 to -15 inHg when active.
Guided diagnostic — the DiagCoach way
Don't just throw parts at it. Walk through these in order — each step tells you whether to keep going or stop and fix what you found.
- 11. Inspect the wiring and connectors related to the secondary air injection system for damage or corrosion. Decision: If damaged, repair or replace; if good, proceed to step 2.
- 22. Check the operation of the secondary air pump by activating the system (if applicable). Use a multimeter to measure voltage and ground at the pump connector. Expected voltage: 12V when active. Decision: If no voltage, trace back to the fuse or relay; if voltage present, proceed to step 3.
- 33. Inspect the air injection check valve for clogs or failures. Use a vacuum gauge to check for normal operation; vacuum should hold after the pump goes off. Decision: If clogged, clean or replace; if operating normally, proceed to step 4.
- 44. Use a scan tool to monitor live data for airflow and pressure readings from the secondary air injection system. Decision: If readings are out of expected values, further diagnosis of the system is required; if within range, check for potential ECM issues.
Common causes
- Faulty air pump
- Blocked air passages
- Faulty check valve
- Wiring/connectors issue in the system
- ECM malfunction
Typical repair cost
$$
Related codes
Frequently asked questions
Can I still drive my vehicle with this code?
Yes, but expect reduced engine performance and possibly increased emissions, so fix it soon.
Will this code come back after clearing it?
It may return if the underlying issue isn't fixed, such as a defect in the pump or blockage in the air delivery system.
Why does this code sometimes appear with different codes?
This code can show alongside others if there are multiple issues within the air injection system or related components.
Working a real vehicle right now?
Let DiagCoach walk you through it live with your specific symptoms, vehicle, and what you've already checked.
Start guided diagnostic →