P0415 on Audi: Secondary Air Injection System Switching Valve 'B' Circuit
Diagnostic trouble code P0415 on Audi vehicles — what it means, the common
causes, and how to confirm the real fault before replacing parts.
What does P0415 mean?
P0415 indicates: Secondary Air Injection System Switching Valve 'B' Circuit.
This relates to the Emissions / auxiliary emission controls system.
Common causes of P0415
Blockage (restricted flow) in the secondary air injection system
Reduced pumping capacity or a blockage upstream of the secondary air injection sensor
Combination valve open fault
Faulty pressure sensor
Secondary air pump running and not shutting off
Connectors or hoses of secondary air injection valves interchanged
Moisture/water penetrating the vacuum system via breather and ventilation opening
What to check (live data)
Secondary air pump running status (should shut OFF after injection phase)
Pressure difference across secondary air system during diagnosis phases
Oxygen sensor signal during secondary air injection measurement phase (compared against threshold values)
Secondary air mass computed by ECM based on oxygen content change during injection phase
Parts often involved in P0415
Secondary Air Injection Solenoid Valve 2 N320
Secondary Air Injection Solenoid Valve N112
Combination valve (vacuum controlled)
Secondary Air Injection Pump Motor V101
Secondary Air Injection Sensor 1 G609
Vacuum pump
Water separator / filter elements in vacuum hoses
Vacuum hoses
Don't replace parts until the root cause is confirmed — many of these codes are caused by wiring, a connector or an upstream fault, not the part itself.
Get the confirmed root cause for P0415 — on YOUR vehicle
A code is a symptom, not a diagnosis. AutoDX Pro cross-checks several
independent assessments, pinpoints the actual root cause, gives you the
exact tests to confirm it, and shows the parts — only after the cause is
confirmed. Reads your scan-tool photo and decodes your VIN with open
recalls.
P0415 is a diagnostic trouble code: Secondary Air Injection System Switching Valve 'B' Circuit.
What are the common causes of P0415 on an Audi?
Common causes include: Blockage (restricted flow) in the secondary air injection system, Reduced pumping capacity or a blockage upstream of the secondary air injection sensor, Combination valve open fault, Faulty pressure sensor. The exact cause depends on the vehicle — confirm it before replacing parts.
Can I keep driving an Audi with P0415?
It depends on the fault and your symptoms. Some causes are minor, others can damage components or affect safety. Get the root cause confirmed before deciding.
How do I fix P0415 on an Audi?
Confirm the actual root cause with targeted tests first, then replace only the part that's at fault. AutoDX Pro gives you the root cause, the exact tests, and the parts for P0415 on your specific Audi.