P0492 - Secondary Air Injection System Insufficient Flow Bank 2
The P0492 code indicates that the engine control module (ECM) has detected insufficient airflow in the secondary air injection system on bank 2 of the engine. This system pumps fresh air into the exhaust manifold during cold starts to reduce emissions by helping the catalytic converter reach operating temperature faster. Insufficient flow can be caused by a failed air pump, blocked hoses, a stuck check valve, or a faulty relay. The code is triggered when the ECM monitors the oxygen sensor response and determines that the added air is not reaching the exhaust stream as expected.
01. Most Common Causes
- Failed secondary air injection pump
- Blocked or leaking air injection hoses
- Stuck closed or failed check valve
- Faulty air pump relay or fuse
02. Symptoms You Will Notice
- Check Engine Light illuminated
- Rough idle or hesitation during cold start
- Failed emissions test
- Possible reduced fuel economy
03. Step-by-Step Diagnosis
Step 1: Use a scan tool to confirm P0492 and check for related codes.
Step 2: Inspect the air pump, hoses, and check valve for damage, blockages, or leaks.
Step 3: Test the air pump relay and fuse with a multimeter.
Step 4: Activate the air pump with a scan tool and verify airflow at the exhaust manifold.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
Yes, but the vehicle may fail an emissions test and the check engine light will remain on. It's best to repair it soon to avoid potential catalytic converter damage.
How much does it cost to fix?▼
The cost typically ranges from $50 to $150 for parts like a relay or hose, but if the air pump needs replacement, it can be $200-$400 including labor.