What it means
The secondary air injection system on bank 2 delivers more flow than calibrated when the pump is commanded on - typically a stuck-open switching valve allowing free flow.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
The Bank 2 secondary air injection system directs pump air into the exhaust through its switching valve during cold start. The engine control module monitors the system response and detects when airflow is higher than its calibrated range while the pump is commanded on. P2449 points to excessive flow on Bank 2, which may result from a valve stuck open, a pump that stays on, or damaged air plumbing.
Common causes
Most likely first.
- AIR switching valve stuck open or leaking
- Faulty AIR pump relay or control circuit keeping the pump on
- Damaged air plumbing or leaking check valve
Symptoms
- Check engine light on
- Rough idle or hesitation during cold start
- Unusual air-pump noise
- Failed emissions inspection
How to diagnose it
- Review freeze-frame and live scan-tool data to confirm the excessive-flow indication is associated with Bank 2 secondary-air operation.
- Inspect the Bank 2 switching valve, pump relay, wiring, hoses, and check valve for sticking, leaks, damage, or unintended pump operation.
- Compare the Bank 2 pump command with its actual operation and check whether the pump stops when commanded off.
- Test the switching valve and pump control circuit, including the relay, using the wiring diagram and manufacturer’s specification.
- Check Bank 2 air hoses and the check valve for leaks or damage that could allow excess or unintended airflow.
Common fixes
- Free or replace a Bank 2 switching valve that is stuck open or leaking.
- Replace a faulty pump relay that leaves the pump powered.
- Repair damaged Bank 2 pump control wiring or connectors.
- Repair leaking or damaged Bank 2 air hoses or check valve.
Can I keep driving?
If the engine runs normally, drive only as needed to arrange repair; cold-start hesitation and an emissions inspection failure may occur. Stop if the pump develops severe noise or engine performance worsens significantly.
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.