Audi P0491 and P0492 together: secondary-air restriction diagnosis. See the manufacturer document, vehicle conditions, exclusions and questions for a qualified shop before assuming a repair.
This is a research summary of a manufacturer communication, not a diagnosis for your car, a DIY repair procedure or confirmation of warranty or recall eligibility. No qualified technician has approved a repair for your individual vehicle here.
This historical communication is conditional. The current revision, VIN/build eligibility, measured diagnosis and any warranty or recall decision are not established here. Ask the manufacturer or a qualified shop to check the complete current document.
Read the Audi original: Secondary-air restrictions P0491/P0492 · Check open recalls by VIN at NHTSA Source date: 2019-01-25; research checked: 2026-11-01.
What prompted this manufacturer document
- MIL with both codes
- Mileage over 15,000
- Cylinder-head secondary-air passages can accumulate carbon. The repair route requires testing, including pump behavior and air-path leakage checks.
Which vehicle conditions must be checked
Each row below retains its own conditions. Do not combine engines, years or models across rows to create new applications. A listed model is not proof that a particular VIN is affected.
- Audi A6 · 2009, 2010, 2011, 2012, 2013, 2014, 2015, 2016 · 3.2 FSI AVS / 3.0 TFSI grouped equipment in source; gasoline
- Audi A7 · 2013, 2014, 2015, 2016 · 3.2 FSI AVS / 3.0 TFSI grouped equipment in source; gasoline
- Audi S4 · 2010, 2011, 2012 · 3.2 FSI AVS / 3.0 TFSI grouped equipment in source; gasoline
- Audi A8 · 2011, 2012, 2013, 2014, 2015, 2016 · 3.2 FSI AVS / 3.0 TFSI grouped equipment in source; gasoline
- Audi Q7 · 2011, 2012, 2013, 2014, 2015, 2016 · 3.2 FSI AVS / 3.0 TFSI grouped equipment in source; gasoline
- Audi A5 · 2010, 2011, 2012, 2013, 2014, 2015, 2016 · 3.2 FSI AVS / 3.0 TFSI grouped equipment in source; gasoline
- Audi S5 Cabriolet · 2010, 2011, 2012, 2013, 2014, 2015, 2016 · 3.2 FSI AVS / 3.0 TFSI grouped equipment in source; gasoline
- Audi Q5 · 2010, 2011, 2012, 2013, 2014, 2015, 2016 · 3.2 FSI AVS / 3.0 TFSI grouped equipment in source; gasoline
- Single-code result alone is not the stated dual-code condition.
Codes recorded in this document
A root listed only as an appearance has no separately verified meaning here. Preserve every suffix and module name; a shared root does not transfer a repair branch to another vehicle.
| Root | Raw form | Meaning in this source, if established |
|---|---|---|
| P0491 | P0491 | Insufficient secondary-air flow, bank 1 |
| P0492 | P0492 | Insufficient secondary-air flow, bank 2 |
What an owner can record safely
- Both codes rather than a single code
- Mileage
- Prior pump or emissions work
Editorial safety boundary for this system
A steady lamp without severe symptoms still needs diagnosis; this is not blanket permission for continued driving.
- Use current model-specific service information, calibrated equipment and a qualified technician for the selected diagnostic branch.
- Do not bypass emissions controls or buy pumps/sensors from a code alone.
This is a conservative editorial policy, not a manufacturer safe-to-drive decision for a specific vehicle.
What the source does not prove
- Do not automatically sell two oxygen sensors or an air pump. Do not expand the shared engine column into every model/engine combination.
- A code or message alone does not establish a failed part, a safe-to-drive decision or an approved repair for this VIN.
- A service bulletin is not automatically a recall or free warranty repair. Confirm current eligibility directly.
Questions for the repair shop
- Which current manufacturer procedure, VIN/RPO/build gate and test result determine the diagnostic branch?
- Does a later revision or a current recall change the source's original advice?
- What measurement or inspection confirms the cause, and how will the repair be verified?
Open source-review issue
- Q3-10: Shared engine/RPO columns cover several model rows. Never produce a Cartesian product of every engine and every year/model. Verify VIN/RPO pairing first.
The uncertain field is not used here to claim a current fitment, repair or market-wide failure.
Read the original record
The linked communication may be revised after the research date. Compare its document number, exact vehicle table, diagnostic preconditions and exclusions with a qualified technician. This page paraphrases selected facts and does not reproduce the manufacturer procedure.
Sources and scope
- Audi — Secondary-air restrictions P0491/P0492 (2033001/18) Document: 2019-01-25 · Research checked: 2026-11-01
Research snapshot: 2026-11-01. Source documents may have newer revisions. Verify current instructions and VIN eligibility with the manufacturer.