P0412

Q: What does OBD2 code P0412 mean?

P0412 means: Secondary Air Injection System Switching Valve A Circuit Malfunction. The secondary air injection switching valve, which directs air into the exhaust during cold start to reduce emissions, has a circuit fault.

Secondary Air Injection System Switching Valve A Circuit Malfunction

The secondary air injection switching valve, which directs air into the exhaust during cold start to reduce emissions, has a circuit fault.

SeverityMinor

CategoryEmissions

Est. Repair Cost$120-$300

Code TypePowertrain

DIY RepairYes

⚡ Common Causes

›Faulty switching valve
›Damaged wiring
›Blown fuse
›Failed air pump relay

⚠️ Symptoms

›Check engine light
›Possible failed emissions test
›No noticeable driveability issue

✅ How to Fix — Step by Step

Step 1:Inspect valve wiring and connector
Step 2:Test valve operation
Step 3:Replace valve if faulty

🔧 Diagnostic Tools Required

✔OBD-II Diagnostic Scanner
✔Digital Multimeter
✔Basic Hand Tools
✔Flashlight
✔Vehicle Service Manual

Using the correct diagnostic tools helps identify the root cause of P0412 before replacing parts unnecessarily. Always confirm the fault using live data and manufacturer-recommended diagnostic procedures.

💡 Pro Tip: This system only runs briefly after a cold start, so a fault here rarely affects normal driving - but it will fail an emissions test.

Repair Cost Estimate

Full Repair Estimate

$120-$300

DIY Possible?

YES

Severity

Minor

Frequently Asked Questions

What does OBD2 code P0412 mean?+

P0412 stands for Secondary Air Injection System Switching Valve A Circuit Malfunction. The secondary air injection switching valve, which directs air into the exhaust during cold start to reduce emissions, has a circuit fault.

What causes code P0412?+

Faulty switching valve; Damaged wiring; Blown fuse; Failed air pump relay

How do I fix code P0412?+

Inspect valve wiring and connector; Test valve operation; Replace valve if faulty

How much does it cost to fix P0412?+

Estimated repair cost for P0412 is $120-$300.

Is P0412 DIY-friendly?+

Yes — P0412 is generally DIY-friendly with basic tools.