P0415Generic code

P0415 Code: Secondary Air Injection System Switching Valve B Circuit

The P0415 code means the computer found an electrical fault in the control circuit of secondary air switching valve B. Fuses, relays, connectors and wiring are the usual cause, so check those before you replace the valve. It does not affect driving, but it keeps the vehicle from passing an emissions inspection.

Severity
Low
Can I keep driving?
Yes, no immediate risk
Estimated cost
$50 to $500
Difficulty
Medium
System
Emissions Control
Applies to
All OBD2 vehicles

Updated Reviewed by Renzo Chacca

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What the P0415 code means

On engines with two banks or two valves, valve B controls the secondary air flow to the second bank or to a second point in the exhaust.

The computer watches the control circuit from its own driver transistor. The P0415 code points to an electrical fault in that control circuit. Before you replace the component, check the fuse, the relay, the connector and the wiring, because they are the most common cause.

If valve B fails, one bank gets no air after a cold start. It does not affect driving, but it keeps the vehicle from passing an emissions inspection.

Always start with the simplest things: the fuse, the relay and the connector. Then check supply, ground and signal with the component connected, using back-probes, and finally the continuity of each wire to the computer. Replace the component only if all of that checks out.

P0415 code symptoms

  • Check engine light on.
  • Usually no driving symptoms.

Likely causes of the P0415 code

  1. Damaged connector. Loose, broken or corroded.
  2. Fuse or relay blown or with worn contacts.
  3. Wiring cut or shorted between the component and the computer.
  4. Failed component. The coil, the motor or the internal electronics are damaged.

How to diagnose the P0415 code step by step

  1. Activate the component with the scan tool and see whether it responds.
  2. Check the fuse and the relay.
  3. Measure the supply at the connector. You should see battery voltage with the key on or when it is activated.
  4. Measure the resistance of the component and compare it with the manual. Check the insulation to ground too.
  5. Check the control wire for continuity and for the absence of shorts.
  6. Identify valve B in the manual.
  7. Activate the valve with the scan tool.

How to fix the P0415 code

  • Repair the connector, the wiring or the supply.
  • Replace secondary air switching valve B if it does not respond with correct supply and control.
  • Clear the codes and verify that the monitor completes.

Technical reference data

  • 12 volt solenoid.
  • These are approximate values, so check the manufacturer data for your engine.

Brand-specific notes

This valve is used on V6 and V8 engines. Make sure you know which valve is B before you start testing, because the layout changes from one engine to the next.

P0415 on Toyota

Used on Toyota V6 and V8 engines.

P0415 on Lexus

Used on Lexus V6 and V8 engines.

P0415 on GM

Used on GM V6 and V8 engines.

Frequently asked questions about P0415

Can I drive with a P0415 code?
Yes. It normally does not affect driving. Repair it before the emissions inspection.
What does secondary air switching valve B do?
On engines with two banks or two valves, valve B controls the secondary air flow to the second bank or to a second point in the exhaust.
Do I always have to replace the part?
No. Check the fuses, relays, connectors and wiring first.
How much does it cost to fix P0415?
Roughly $50 to $500, depending on whether it is wiring or the valve itself. Diagnosing the P0415 code properly first keeps you from paying for parts you do not need.
What does the P0415 code mean?
It is a generic OBD2 code for a malfunction in the control circuit of secondary air switching valve B. The computer saw an electrical problem there.
Will a P0415 code clear itself?
Only if the fault was a one-time glitch. A bad connector or a failed valve will bring the code back on the next cold start.

Related codes

Questions about the P0415 code

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