P0492 on 1997-2003 Audi A8 (4.2 quattro, S8) — Secondary Air Injection System Insufficient Flow (Bank 2)
1 vehicles · 1 makes · $80-$1,400 repair
Most Reported On
P0492 is an OBD-II diagnostic trouble code meaning “Secondary Air Injection System Insufficient Flow (Bank 2).” This code means the PCM determined that the secondary air injection system is delivering insufficient airflow into the exhaust on Bank 2. The system injects fresh air into the exhaust at cold start to speed catalytic converter warm-up and reduce emissions. Insufficient flow on Bank 2 indicates a blockage, leak, or weak pump affecting that bank. It generally triggers the check engine light and impacts cold-start emissions rather than normal driving. This code is most commonly reported on 1997-2003 Audi A8 (4.2 quattro, S8), with repair costs ranging from $80 to $1,400.
Common Causes
Typical Repair Cost
Based on 1 documented vehicle-specific issues. Actual cost depends on root cause and vehicle.
Diagnostic Tools
To diagnose P0492, you'll need an OBD-II scanner. Here are our recommendations at every price point.
ANCEL AD310 Classic OBD-II Scanner
by ANCEL
A simple, affordable code reader that reads and clears check engine codes. Great for quick diagnostics on any OBD-II vehicle (1996+).
- Read & clear engine codes
- View freeze frame data
- I/M readiness status
- No batteries or app needed
BlueDriver Pro Bluetooth Scanner
by BlueDriver
Bluetooth OBD-II scanner with a free companion app. Provides enhanced diagnostics, smog readiness, and repair reports sourced from a database of verified fixes.
- Enhanced diagnostics (ABS, SRS, transmission)
- Repair Reports with verified fixes
- Smog check readiness
- Free app (iOS & Android)
LAUNCH CRP123X OBD-II Scanner
by LAUNCH
A professional-grade handheld scanner that reads all four major systems (engine, transmission, ABS, SRS) with live data streaming and graphing.
- Engine, transmission, ABS, SRS diagnostics
- Live data stream & graphing
- AutoVIN for vehicle identification
- Free lifetime updates via Wi-Fi
Autel MaxiCOM MK808S Diagnostic Tool
by Autel
Shop-level diagnostic tablet with bi-directional control, active tests, and full system coverage. Ideal for serious DIYers and small shops.
- All-system diagnostics (25+ modules)
- Bi-directional control & active tests
- Oil reset, EPB, BMS, TPMS, injector coding
- 7-inch touchscreen with Android OS
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FAQ
What does P0492 mean?
P0492 stands for "Secondary Air Injection System Insufficient Flow (Bank 2)." This code means the PCM determined that the secondary air injection system is delivering insufficient airflow into the exhaust on Bank 2. The system injects fresh air into the exhaust at cold start to speed catalytic converter warm-up and reduce emissions. Insufficient flow on Bank 2 indicates a blockage, leak, or weak pump affecting that bank. It generally triggers the check engine light and impacts cold-start emissions rather than normal driving.
What are the most common causes of P0492?
The most common causes of P0492 are: Clogged or restricted secondary air injection passages (Bank 2), Failing secondary air injection pump, Stuck or leaking air switching/check valve, Vacuum or hose leak in the air injection plumbing, Carbon buildup blocking air delivery ports, Electrical fault in the pump or valve circuit. The specific cause varies by vehicle.
How much does it cost to fix P0492?
Repair costs for P0492 range from $80 to $1,400, depending on the vehicle and root cause.
Which vehicles are affected by P0492?
Au7o has documented P0492 across 1 vehicle models from 1 manufacturers: Audi.
Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.