Secondary Air Injection System Sensor Circuit High
Indicates a problem with the secondary air injection system sensor circuit.
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 helps reduce emissions by injecting air into the exhaust stream. The computer monitors the sensor that tracks this process. If the sensor sees high voltage when it shouldn’t, it triggers this code.
What the computer is actually seeing
The engine control module (ECM) looks at the voltage from the secondary air injection system sensor. It expects voltages typically between 0.5V and 4.5V. If it reads above 4.5V, it sets this code.
What a healthy reading looks like
0.5V to 4.5V
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. Check the wiring and connectors going to the secondary air injection sensor for damage, corrosion, or loose connections. If damaged, repair or replace as needed. Decision: Is the wiring intact? Yes: go to step 2. No: repair/wire and retest.
- 22. Measure the voltage at the secondary air injection sensor connector with the ignition on and engine off. Expected value is 0.5V to 4.5V. Decision: Is the voltage within range? Yes: go to step 3. No: replace the sensor.
- 33. With the engine running, check for proper operation of the secondary air injection system. Listen for the operation of the pump and ensure air is being injected during the appropriate cycle. Decision: Is the system working? Yes: indicate a potential ECM issue. No: mechanical or pump issue, replace as necessary.
Common causes
- Wiring issues in the sensor circuit
- Faulty secondary air injection system sensor
- Failed secondary air injection pump
- Blown fuse in the air injection system circuit
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
Yes, but emissions may be higher and should be addressed soon.
Will this code come back after reset?
If the underlying problem isn't fixed, the code will likely return.
Why is this code paired with other P041 codes?
Often, multiple codes indicate issues in the same air injection system circuit or 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 →