P0413–P0416 AIR System Switching Valve A Circuit Open
The circuit is broken somewhere - a cut wire, a corroded pin or an unplugged connector means the signal never arrives.
Can you drive it? The engine light will stay on and the car may run in a reduced-power mode. Read the freeze-frame data to see the conditions the fault was logged under.
Which code is which
Same fault, different cylinder or bank — diagnosed the same way. Several set together usually means one shared cause.
| Code | Definition | Severity |
|---|---|---|
P0413 | AIR System Switching Valve A Circuit Open | Investigate soon |
P0416 | AIR System Switching Valve B Circuit Open | Investigate soon |
The definition
P0413: AIR System Switching Valve A Circuit Open.
P0413 is a powertrain code (the engine or gearbox), defined by the SAE standard - it means the same thing on any make of car, and any generic OBD-II reader will decode it.
What to check first
Cheapest and fastest checks first:
- Check the connector is fully seated and the locking tab is engaged. A half-seated plug is the single most common cause of an open circuit.
- Back-probe the pins and check continuity from the part back to the module connector.
- Inspect for a pushed-back or corroded terminal - the wire looks fine but the pin has backed out of the housing.
What actually causes this on a VAG
Same changeover valve as P0412, but here the ECU is specifically reporting an open circuit: when it drives and monitors that output it sees no load connected at all. That's a broken wire, an unplugged or badly corroded connector, or a solenoid whose winding has gone open - not a mechanical air-flow problem. On VAG petrol engines this valve is small, tucked away and easy to disturb during other work.
Most likely causes, in order
- Connector unplugged or not clipped home. Very common after work in that area - inlet off, coil packs out, engine cover removed. It costs nothing to look, so look first: push the plug on properly and check the locking tab has actually engaged.
- Broken wire in the loom. A conductor broken inside intact-looking insulation gives a fault that comes and goes with engine movement or temperature. Wiggle the loom section by section with an output test running and see when it reappears.
- Open-circuit solenoid coil. Heat and age break the winding. Command the valve in an output test and listen for the click, then check for continuity across its two pins. No click and no continuity means the valve.
Worth knowing: Check the plug before you order anything. An open circuit here is as often a connector that's been knocked off as a failed part, and this valve is one of the least expensive items in the whole secondary air system - so it's an easy one to buy unnecessarily. After a repair, don't assume a cleared code means it's fixed: give it another cold start so the ECU actually exercises the circuit again.
Reading the code is the easy part
A code names the circuit that complained. What tells you why is watching the sensor behind it while the engine runs — and that is where a code reader stops and a diagnostic tool starts.
VAGPULSE reads every module in a VW, Audi, Skoda or SEAT — not just the engine — shows the live measuring blocks behind this fault, gives you the freeze-frame conditions it was logged under, and clears it once you have fixed it. It also does what a generic OBD reader cannot on a VAG: service resets, coding, adaptations, and Stage 1–3 flashing with your original file saved first.
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Common questions
What does P0413 mean?
P0413 means AIR System Switching Valve A Circuit Open. The circuit is broken somewhere - a cut wire, a corroded pin or an unplugged connector means the signal never arrives.
Can I drive with P0413?
The engine light will stay on and the car may run in a reduced-power mode. Read the freeze-frame data to see the conditions the fault was logged under.