Guide to the 2007-2012 Audi S6 Secondary Air Injection Control Valve
If you have a check engine light for the secondary air system on your S6 V10, read this before buying any parts.
- A check engine light with codes P0411, P0491, or P0492 is the primary symptom of a fault in the SAI system.
- Before replacing any parts, have the system diagnosed for carbon-clogged air passages in the cylinder heads, a very common issue on the S6 V10.
- Replacing the valve or pump will not fix the codes if the air passages are blocked.
- Hella is a trusted, OEM-quality brand for these components if a replacement part is truly needed.
Understanding Failures on the S6 V10
When the secondary air injection (SAI) system on your 2007-2012 Audi S6 has a problem, the first thing you will likely notice is the check engine light on your dashboard. This is often caused by Diagnostic Trouble Codes (DTCs) like P0411, P0491, or P0492, which indicate incorrect or insufficient airflow. 🎬 Watch: Understanding the P0491 and P0492 fault codes You might also hear a loud noise like a vacuum cleaner for a minute after a cold start, which points to a failing air pump motor.
CRITICAL: Check for Carbon Buildup Before Replacing Parts
On the Audi S6 V10 engine, the most common cause for P0491 and P0492 codes is not a failed valve or pump. The issue is often severe carbon buildup inside the small air passages in the cylinder heads. Audi has issued Technical Service Bulletins (TSBs) about this exact problem. If these passages are clogged, the air from the pump can't get through, which triggers the "insufficient flow" code. Replacing the pump or valve will not fix the problem if the ports are blocked. Proper diagnosis is essential before you spend money on parts you may not need.
Choosing the Right Aftermarket Part
If diagnosis confirms you do need a new valve, you have a choice between OEM and aftermarket options. The "Secondary Air Injection Control Valve" can refer to different parts, including the electronic solenoid that controls vacuum, or the larger mechanical "combi" valves on the engine. Be sure you are ordering the correct part.
- Tier 1 / OEM Quality (Hella): Hella is a well-respected brand that often supplies parts directly to Audi. Parts from Hella or its partner Pierburg are considered equivalent to original equipment in fit and quality. Choosing this tier gives you the highest confidence in the part's longevity and performance.
- Tier 2 / Standard Aftermarket (Vaico): Vaico is a known aftermarket brand that offers a more budget-friendly alternative. These parts meet basic fit and function requirements and are a good option for less critical repairs or for vehicle owners on a tighter budget. While generally reliable, they may not have the same long-term durability as an OEM-quality part.
Part & Labor Cost Estimates
| Item | Estimated Cost |
|---|---|
| New Aftermarket Valve | $14 - $88 |
| New OEM Valve | $250 - $450 |
| Shop Labor (Valve Replacement) | $120 - $250 |
| Shop Labor (Carbon Port Cleaning) | $1,500 - $2,500+ |
Frequently Asked Questions
What's the difference between the control valve, combi valve, and air pump?
The air pump is an electric motor that creates the air pressure. The combi valve (combination valve) is a mechanical check valve mounted to the engine that allows this air into the exhaust but stops exhaust from flowing back. 🎬 Watch: How to replace the secondary air injection combi valve The control valve (solenoid valve) is an electronic part that uses vacuum to open and close the combi valve. All three must work correctly.
I replaced the valve, but the check engine light came back. Why?
This is a very common situation for S6 owners. The most likely reason is that the secondary air ports in your engine's cylinder heads are clogged with carbon. Even with a new pump and valve, the air cannot flow through the clogged passages, which re-triggers the fault code. The fix is a professional and labor-intensive cleaning of these ports.
Can I just clean the valve instead of replacing it?
Sometimes a combi valve can be cleaned if it is sticking due to light carbon deposits. However, this is often a temporary fix. More importantly, it does not address the main issue on these engines, which is the clogging of the air passages deep inside the cylinder head.
Is there a recall for the secondary air injection system on my Audi S6?
No, there are no active recalls from Audi or NHTSA for the secondary air injection system on the 2007-2012 Audi S6. There are, however, multiple Technical Service Bulletins (TSBs) that instruct dealers on how to diagnose and clean the carbon-clogged ports.
Helpful Videos
Technical Specifications
OEM Part Numbers: 078131101AG 078131102T 037906283C
This guide refers to the vacuum-operated combination valves (combi valves) and the electronic solenoid that controls them. The system also includes an electric air pump and various hoses.
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The information in this article is provided for general reference and educational purposes only. Vehicle specifications, procedures, and part compatibility can vary by production date, trim level, and region. Always consult your vehicle's factory service manual and verify part numbers before purchasing or performing repairs. Safety-critical components such as airbags, seat belts, and braking systems should be installed by a qualified professional.
- Audi S6: