What it means
The switching/check valve in the secondary air injection plumbing on bank 2 is stuck in the open position. With the valve permanently open, exhaust gas can back-feed into the air pump and corrode it, while the downstream O2 sensor sees ambient air constantly.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
The secondary air injection switching valve for bank 2 controls airflow into that bank's exhaust during cold starts to help the catalyst warm up. This code sets when the bank 2 valve remains open when it should close, which can let exhaust backflow through the air plumbing, expose the pump to corrosion, and affect oxygen-sensor readings.
Common causes
Most likely first.
- Switching valve stuck open
- Carbon or debris buildup preventing free movement
- Component wear with age - mechanical play
Symptoms
- Check engine light on
- Rough or elevated idle during cold start
- Reduced engine performance
- Unusual air-pump noise
How to diagnose it
- Use a scan tool to check freeze-frame data and command the bank 2 secondary air system on and off, watching for valve response and changes in oxygen-sensor data.
- With the engine cold and off, inspect the bank 2 switching valve and air pipes for carbon, corrosion, heat damage, or signs of exhaust backflow.
- Check the bank 2 valve connector and wiring, plus any vacuum-control line used on this vehicle, for looseness, damage, or leaks.
- Test whether the bank 2 valve moves and seals when commanded, following the vehicle's service procedure.
- If the valve remains open, inspect the secondary air pump and related plumbing for damage caused by exhaust backflow.
Common fixes
- Repair a damaged bank 2 valve connector, wiring, or leaking control line.
- Clean carbon or debris from the bank 2 switching valve if the service procedure allows it.
- Replace the bank 2 switching valve if it cannot close and seal reliably.
- Replace a secondary air pump damaged by backflow after correcting the stuck-open valve.
Can I keep driving?
Avoid prolonged driving if the air pump is noisy or the system shows signs of exhaust backflow, and arrange repair soon to limit the risk of pump corrosion or failure. The bank 2 cold-start emissions fault may also cause rough or elevated idle and an emissions test failure.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.