P0415 OBD-II Trouble Code: Secondary Air Injection System Switching Valve B Circuit Malfunction

Check Engine Light

P0415 code definition

This is the generic OBD-II fault code for Secondary Air Injection System Switching Valve B Circuit Malfunction. B refers to a specific area of the system’s circuitry.

What the P0415 code means

The secondary air injection system pumps ambient air into the engine’s exhaust system in order to reduce emissions. This code will set when the PCM (powertrain control module) has received a voltage signal from the secondary air injection system which falls outside of the expected parameters, as defined by the manufacturer’s specifications.

What causes the P0415 code?

This problem is most commonly triggered in cold weather conditions. When the one-way check valve which protects the secondary air injection pump goes bad, water in the form of condensation gets into the pump and locks it up. This can cause pump failure, or overload the electrical circuit, blowing the fuse.

Another possibility is that engine exhaust that has become too hot and has damaged the wiring and connections involved in the air injection system.

What are the symptoms of the P0415 code?

In addition to the stored Diagnostic Trouble Code (DTC), the Malfunction Indicator Lamp (MIL) will likely eventually come on, although it could take repeated drive cycles for this to happen. Other signs may include hesitation when accelerating, stalling at idle or startup, and/or unusual noises generating from the secondary air injection system.

How does a mechanic diagnose the P0415 code?

Diagnostic procedures may include:

  • Verifying any set DTCs, and capturing freeze frame data, including the order in which the codes occurred

  • Clearing all codes and test driving the vehicle to see if they return (if they don’t, this could indicate an intermittent condition, which is trickier to diagnose)

  • Visually inspecting all system wiring and connectors for damage or shorts

  • Inspecting secondary air injection system fittings and hoses for cracks, breaks, or heat damage

  • Testing system fuses, replacing, and running the secondary air injection system to see if the fuses blow again (indicating possible pump failure)

  • Inspecting the one-way check valve to see if it’s allowing condensation to enter the pump

Diagnosing this failure will require a scanner as well as a digital volt/ohmmeter. A qualified technician has all the tools necessary to thoroughly investigate the issue and get it repaired quickly and efficiently.

Common mistakes when diagnosing the P0415 code

Replacing the secondary air injection pump without installing a water drain on the pump housing can lead to repeated pump failure. Neglecting to inspect the check valves may also be overlooked, when in fact this is one of the most common causes of this type of issue.

How serious is the P0415 code?

Even if you’re not experiencing any drivability issues, the secondary air injection system is a critical component of controlling emissions. This means that you could fail emissions testing if it’s required in your state. If the Check Engine Light illuminates, this will also disqualify your vehicle from passing the inspection.

What repairs can fix the P0415 code?

In order to rectify this situation, your mechanic may:

Additional comments for consideration regarding the P0415 code

Technicians find that the most common problem which triggers this code is water entering through a failed check valve in the secondary air injection system pump. This condensation then freezes, causing the pump to lock up and triggering the DTC to set.

If your vehicle has an engine with a V configuration, there are likely dual inlet ports with dual check valves. These valves should be tested by trying to pump air through them in both directions. If you’re unsure what kind of setup your engine has, consult with a professional mechanic.

Need help with a P0415 code?

YourMechanic offers certified mobile mechanics who will come to your home or office to diagnose and repair your vehicle. Get a quote and book an appointment online or speak to a service advisor at 1-800-701-6230.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

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