OBD-II trouble code
P0417: Secondary Air Injection System Switching Valve B Circuit Shorted
The control circuit for secondary air switching valve "B" is shorted — the computer sees excessive current or an always-live circuit when it should be off.
Quick facts
- System
- Powertrain
- Category
- Emissions / Secondary Air
- Severity
- Low severity
- Drivable
- Usually safe to drive short-term
- Repair cost range
- $80 – $500
- DIY difficulty
- Advanced DIY
Browse every code in P0400–P0499, or start from the full code library.
What does P0417 mean?
P0417 is the short-circuit counterpart to P0416: instead of no current, the computer sees too much — the valve "B" control circuit is shorted to ground or to voltage, or the solenoid winding itself has shorted internally so its resistance is far below spec.
Shorted solenoid windings are a genuinely common failure: heat cycling breaks down the winding insulation until adjacent turns touch, dropping resistance and spiking current. The other classic is chafed harness insulation grounding the control wire against the engine or body — the valve then buzzes on constantly or the driver circuit shuts down to protect itself. Some PCMs disable the driver entirely once they detect a short, so the whole AIR system may go quiet.
Measure the solenoid's resistance first, and measure it unplugged, across the valve's own two terminals. That isolation is the whole test: with the harness still connected, a control wire shorted to ground reads as a near-zero resistance and looks exactly like a collapsed winding, so the measurement condemns the valve for the harness's fault. Isolated and well below spec condemns the valve; isolated and on-spec sends you hunting the harness for a chafe point. As with the whole AIR family, drivability impact is small but emissions-test failure is guaranteed while the code is set.
Common causes
- Internally shorted solenoid winding in the switching valve
- Control wire chafed and shorted to ground
- Wiring shorted to battery voltage
- Moisture/corrosion bridging connector terminals
- Heat-damaged insulation near exhaust components
- PCM driver damage from a long-standing short (rare)
Symptoms
- Check engine light on
- Failed emissions test
- Blown AIR fuse in some configurations
- Valve possibly buzzing or stuck energized
- Little or no drivability change
Diagnostic steps
- 1.With the exhaust cool and the valve unplugged, measure valve B solenoid resistance across its own terminals and compare to spec — a very low reading on an isolated valve means an internal short; replace it. Measured with the connector still on, a harness short to ground produces the same low reading and will cost you a valve that was never faulty.
- 2.If resistance is normal, disconnect the valve and check the control wire for a short to ground and to voltage.
- 3.Inspect harness routing for chafe points against brackets, the block, or exhaust heat shields.
- 4.Check the connector for moisture or corrosion bridging terminals.
- 5.After repair, verify commanded operation with a scan tool and confirm the driver isn't damaged.
- 6.Run a full cold-start cycle to confirm the code stays clear.
Repair cost
$80 – $500
A replacement switching valve runs $50-$200 plus labor; harness repairs are usually cheaper. If the short blew a fuse or has been present a long time, verify the PCM driver still works before finishing the job.
Estimate your repair
Run the numbers for your vehicle
Open the Repair Cost Estimator with secondary air injection pump replacement preselected. Adjust labor rate and vehicle category to fit your situation.
DIY vs shop
This is an advanced DIY job. It typically requires specialty tools, scan-tool access, lifting equipment, or careful sequencing to avoid causing new failures. Plan for extended downtime and have a backup vehicle. Most owners are better served by a shop that has done this repair before.