P0492 Secondary Air Injection System Insufficient Flow (Bank 2)

P0492 indicates insufficient secondary air injection flow on Bank 2. The controller did not see the expected Bank 2 exhaust response during secondary air operation.

Code details

Generic OBD-II · P0

System: Emissions
Code type: Generic (SAE / ISO controlled)
Standard: SAE J2012 / ISO 15031-6

Diagnostic boundary

A diagnostic trouble code reports that a monitored test failed. It does not prove one specific part is bad, and manufacturer logic can add vehicle-specific conditions.

Do not assume the pump is bad if only Bank 2 has insufficient flow; check bank-specific valves, hoses, and ports.

Symptoms of P0492

Check-engine light, often with no obvious change in how the car drives.
A failed emissions test or incomplete readiness monitors.
Sometimes a faint fuel-vapour smell (on EVAP codes).

Common causes of P0492

A worn catalytic converter or an oxygen/air-fuel sensor reading out of range.
EVAP leaks — a loose or failed gas cap, cracked hose, or purge/vent valve.
Exhaust leaks, fuel-trim problems, or a fault in a related monitor.

Useful checks before replacing parts

Compare secondary air pump command, Bank 2 oxygen sensor response, pressure data, freeze-frame temperature, and monitor enable conditions.
Inspect Bank 2 air hoses, check valves, switching valves, blocked ports, pump output, vacuum control, and signs of water or carbon restriction.
Command the air injection system and verify Bank 2 receives airflow and shows the expected lean response.

Related OBD-II codes

These nearby emissions entries can help compare wording and pin down the fault area.