P0413 code: Secondary Air Injection System Switching Valve A Circuit Open
P0413 means secondary Air Injection System Switching Valve A Circuit Open. The code says where to look, not what failed — the fix depends on which cause your car actually has.
What P0413 means
P0413 means the computer found an open circuit — a break in electrical continuity — in the control circuit for the secondary air injection switching valve. The secondary air system pumps fresh air into the exhaust for the first minute or so after a cold start, which helps the catalytic converter light off quickly and burns leftover fuel in the exhaust. The switching (or combination) valve is what lets that pumped air into the exhaust and then seals it off. An open circuit usually means a failed valve solenoid, a broken wire, a blown fuse, or a corroded connector rather than anything mechanical. Because the system only runs briefly on cold starts, you often notice nothing at all except the light. These systems live in a harsh spot near the exhaust, and moisture-related corrosion in the valve, pump, and connectors is a common failure pattern.
P0413 symptoms
- Check-engine light, often with no drivability change
- Occasionally a rough or noisy cold start
- Secondary air pump not heard running after a cold start
- Failed emissions test
What it costs to fix P0413
Varies by vehicle — get it diagnosed.
The repair cost for this code depends too much on your exact vehicle and the underlying cause to quote a meaningful range. Confirm the cause first so you only pay for the fix you actually need.
Diagnose P0413 for my vehicle →How to fix P0413
Moderate — doable at home with common tools and patience
- Scan for related secondary air codes
Check whether relay, pump, or flow codes for the secondary air system are stored with P0413. An open switching-valve circuit by itself points at that valve's solenoid or wiring; an open circuit alongside a relay or pump code points back toward a fuse or power feed the two parts may share.
- Check the fuse and relay that feed the valve
Find the secondary air fuses and relay in the underhood box using the owner's manual or the fuse-box lid. Test fuses with a meter rather than by eye, and swap the relay with an identical one from a non-critical circuit. A fuse that blows again right away means there's a short to find, not just bad luck.
- Inspect the valve, its connector, and its hoses
The switching valve lives near the exhaust, so check its connector for corrosion and its pigtail for heat damage. Where a solenoid controls a vacuum-operated valve, look over the small vacuum and air hoses too — exhaust heat leaves them brittle and cracked, which won't cause an open circuit but will set flow codes once the electrical fault is fixed.
- Ohm the solenoid and check for power when commanded
Unplug the valve and measure across its terminals: an infinite reading confirms an internally open coil. If the coil reads within spec, command the secondary air system on with a bidirectional scan tool, or check during the first minute after a cold start, and use a test light across the harness pins to see whether power and control actually arrive.
- Repair the failed part and retest from fully cold
Replace whichever part failed — solenoid, combination valve, or a wiring section repaired with solder and heat shrink. The computer only runs this system after a cold start, so let the engine sit several hours or overnight, then start it and confirm the valve and pump operate; the readiness monitor should complete within a few days of normal driving.
DIY or shop? The electrical side of P0413 suits a home mechanic: fuses, a relay swap, a resistance check, and a test light cover most of the diagnosis, and a solenoid mounted in the engine bay is a quick swap. It turns into shop work when the switching valve bolts directly to the exhaust manifold or cylinder head, because heat-seized studs snap easily and a broken stud can mean drilling. A scan tool that can command the air system also makes verification far quicker than waiting for cold mornings.
Tools for the DIY steps: Digital multimeter · 12-volt test light · Bidirectional scan tool · Penetrating oil · Basic socket set · Solder and heat shrink
Not sure which step applies to your car? Get the likely cause for your exact vehicle before buying anything for P0413.
Start a case with P0413 and your car. Redline weighs these causes against what your car shows, and names the check that would settle it before you buy parts.
Can I drive with P0413?
Redline can’t determine from a symptom or code alone whether your car is safe to drive.
P0413: common questions
Is it safe to drive with P0413?
Not from the code alone. The secondary air system only operates for a short period after cold starts, and this is an emissions issue, so handle it before your next inspection.
What does 'circuit open' mean in P0413?
It means the computer sees a break in the electrical path to the switching valve — like a light switch that's disconnected. Common culprits are a failed solenoid coil, a broken wire, a corroded connector, or a blown fuse, not usually a mechanical valve failure.
What does the secondary air injection system do?
It pumps fresh air into the exhaust right after a cold start so leftover fuel burns off and the catalytic converter heats up faster. Once the engine warms up, the system shuts off and stays off for the rest of the drive.
Why do secondary air parts fail so often?
The valves and plumbing sit close to hot exhaust and also collect condensation, so corrosion is common with age. When one part fails it's worth inspecting the pump, valves, and connectors together, since moisture that killed one component often affects the others.
Related trouble codes
Don’t have a scanner yet? A ~$25 Bluetooth adapter reads codes like P0413 from your phone. See our guide to the best OBD2 Bluetooth adapters. Run a repair shop? See Redline for shops.
Generic OBD-II reference. Manufacturer-specific behavior varies. Confirm with a scan tool and, for safety-related codes, a professional inspection. Cost ranges are reference ranges, not quotes.
Seeing P0413 on your car?
Every problem becomes a Case. Tell Redline what the car is doing: it shows what the evidence supports, what’s still missing, and what to check next, before you approve a repair.
“Inner pad ~1 mm. Outer pad 3 mm.”
Next: check the slide pins move freely before buying parts.