P0416 — Problem with secondary air injection valve circuit
The code indicates an electrical issue with the secondary air injection system's switching valve B, meaning the valve's circuit is open or disconnected. This system helps reduce emissions by injecting air into the exhaust to burn off excess pollutants.
Common causes
The cause is almost always one of a few things. Here they are — P0416 rarely comes from anything outside this list:
- Damaged or disconnected wiring to the valve
- Faulty secondary air injection switching valve
- Corroded or loose electrical connectors
- Malfunctioning engine control module (rare)
- Blown fuse related to the air injection system
Where to start
In the order a sensible mechanic would work — the cheap checks first, the expensive replacements only after:
- Inspect and repair wiring and connectors first
- Check and replace blown fuses if needed
- Test and replace the secondary air injection valve
- Verify proper operation of the control module
- Clear codes and test drive to confirm repair
That is what holds for P0416 in general. From here it depends on your engine — tell me which car it is and what it does, and I will give you the steps for it: real procedures, torque figures and diagrams instead of general advice.
Why TorqFix for your car?
Above is what the code means and why it appears. TorqFix goes further — it gives you specific procedures, torque values, wiring diagrams and pinouts for your exact engine, not generic steps for every car. Real workshop data (127,000+ diagrams, 10,000+ procedures), interpreted by AI in your language.
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Code breakdown
🔧 Related repair procedures
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- AUDI: Removing and installing front exhaust pipe (right-side) with catalytic converter - vehicles with manual gearbox
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- AUDI: Removing and installing front exhaust pipe (right-side) with starter catalytic converter and main catalytic converter - vehicles with manual gearbox or multitronic gearbox 01J
- AUDI: Removing and installing catalytic converter
- AUDI: Removing and installing front exhaust pipe (left-side) with catalytic converter - vehicles with multitronic gearbox
- AUDI: Removing and installing catalytic converter - vehicles with two turbochargers
- AUDI: Removing and installing catalytic converter with exhaust pipe - vehicles with engine code letters AVF, AWX
- AUDI: Checking Lambda probe and Lambda control after catalytic converter
Who makes these pages, and how
TorqFix was built by a mechanic — after a 2,700 km drive with five roadside repairs that no diagnostic tool could explain.
The figures on this page come from manufacturer workshop documentation and are shown as they are. The page is assembled automatically from that data — it is not written by an AI. The AI works in the chat, where it answers for your specific car. It writes nothing here.
The same code can mean different things on different makes. Match the meaning to your make before acting on it.
Seen a figure that does not match your manual? Write to us — we correct it and note when. support@torqfix.com
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