P0413
Secondary Air Injection System Switching Valve A Circuit Open
The appearance of the standard OBD2 trouble fault code P0413 is an indicator that your vehicle ECU triggered a threshold alert for "Secondary Air Injection System Switching Valve A Circuit Open". Understanding the root component breakdown helps avoid expensive diagnostic fees.
Driver's Summary
Your vehicle's computer logged P0413 after detecting a malfunction in the secondary air injection system switching valve a circuit open system. In practice, this fault causes check engine light on, no drivability symptoms. This code won't leave you stranded, but it indicates a real issue that will only get easier and cheaper to fix sooner rather than later.
Symptoms
Check engine light on, no drivability symptoms
Common Causes
- Unplugged AIR switching valve
- Broken wire in the control circuit
- Failed solenoid inside the valve
- Blown fuse
How to Fix
- 1 Ensure valve connector is seated
- 2 Repair broken wiring
- 3 Replace the switching valve
- 4 Replace blown fuse
Technical Explanation
The ECM detects code P0413 by continuously monitoring the relevant sensor circuit against calibrated threshold values stored in its non-volatile memory. The PCM commands the relevant emission control valve or solenoid and then verifies system response through a dedicated feedback mechanism — either a position sensor, a downstream pressure sensor, or changes in O2 sensor activity patterns. The MIL illuminates after the fault is confirmed on two consecutive drive cycles, and the freeze frame data captured at first detection is stored in the PCM's memory for diagnostic reference.
Is It Safe to Drive?
Immediate safety risk is low with P0413 active. The primary concern is regulatory — this fault will cause a failed emissions test — and the secondary risk is that the small root cause (unplugged air switching valve) becomes a larger problem if ignored for months.
Mechanic's Pro Tip
For P0413, test the solenoid's coil resistance with a multimeter before ordering parts — most solenoids should read between 14 and 40 ohms; an open (infinite resistance) or short (near zero) confirms it's failed electrically. Also verify the PCM is commanding the solenoid by backprobing the connector with a test light during the relevant operating condition — if there's no command signal, the fault is in the PCM or wiring, not the solenoid itself.
Wiring repair: $100; Switching valve: $100 - $250