Failed secondary air injection pump (electric or belt-driven); Leaking or disconnected air injection hoses or pipes; Faulty secondary air injection solenoid or diverter valve; Blown fuse or corroded relay in the air pump circuit; Carbon buildup or blockage in the air injection passages inside the cylinder head; Failed check valve allowing exhaust gas to back up and damage the pump; Wiring damage or poor ground connection at the air pump

DTC codes / P04xx · Auxiliary emission controls / P0410

P0410Secondary Air Injection System Malfunction

Q: What does code P0410 mean?

Secondary Air Injection System Malfunction. P0410 means the powertrain control module (PCM) has detected a fault in the secondary air injection (SAI) system, which pumps fresh air into the exhaust to speed catalytic converter warm-up. The PCM monitors the system during cold starts and sets this code when the expected air flow or pressure change is not seen.

P0410 means the powertrain control module (PCM) has detected a fault in the secondary air injection (SAI) system, which pumps fresh air into the exhaust to speed catalytic converter warm-up. The PCM monitors the system during cold starts and sets this code when the expected air flow or pressure change is not seen.

SystemPowertrain

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyIntermediate

AreaAuxiliary emission controls

Symptoms you may notice

Illumination of the check engine light, often with no other symptoms
A slightly rough idle or stumble during the first minute after a cold start
A faint hissing or rushing air sound from the engine bay during cold start
Failed emissions test due to incomplete readiness monitors
Occasional exhaust smell or slight increase in emissions during warm-up
In rare cases, a noticeable loss of power if the air pump seizes and loads the belt

Common causes, most likely first

Failed secondary air injection pump (electric or belt-driven)
Leaking or disconnected air injection hoses or pipes
Faulty secondary air injection solenoid or diverter valve
Blown fuse or corroded relay in the air pump circuit
Carbon buildup or blockage in the air injection passages inside the cylinder head
Failed check valve allowing exhaust gas to back up and damage the pump
Wiring damage or poor ground connection at the air pump

How to diagnose and fix it

Inspect all secondary air injection hoses and pipes for cracks, disconnects, or melted sections
Check the air pump fuse and relay, and test for power and ground at the pump connector during cold start
Command the air pump on with a scan tool and listen for operation; if silent, test the pump motor directly
Test the air injection solenoid or diverter valve for proper vacuum operation and resistance
Remove and inspect the check valve for carbon buildup or sticking, replacing if faulty
Perform a pressure or flow test on the secondary air system to confirm the pump is moving air
If all external components pass, check for carbon blockage in the cylinder head air passages

Before you replace the air pump

A failed check valve often allows exhaust gas to reach the air pump, corroding it; replacing only the pump without the check valve leads to repeat failure.
The PCM may not run the secondary air self-test unless the engine is cold and the ambient temperature is within a specific range, so the code may not reset immediately after repair.
A seized air pump can drag the serpentine belt and cause charging or cooling problems, so a squealing belt on a cold start deserves a quick check of the pump pulley.
Carbon-blocked air passages in the cylinder head can mimic a failed pump, and diagnosing this requires removing the air pipe and inspecting the port.
Some vehicles use a belt-driven air pump that only engages via a clutch; a worn clutch can cause intermittent operation that sets P0410 without a completely dead pump.

Can I keep driving with P0410?

You can usually drive with P0410 because the secondary air system only affects cold-start emissions, but avoid long periods of idling and get it repaired before an emissions test. If the engine runs roughly or you hear belt squealing, have it checked promptly to prevent damage to the pump or belt.

Tools that help

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