P0411 on Audi
Secondary Air Injection System Incorrect Flow Detected
P0411 on Audi vehicles indicates secondary air injection system incorrect flow detected. Au7o has documented this code across 1 Audi model — most commonly on A8. This emissions code means the secondary air injection system is flowing an incorrect amount of air. That system pumps fresh air into the exhaust shortly after a cold start to help the catalytic converter heat up and burn off pollutants faster. The computer monitors the resulting change in exhaust oxygen readings, and sets this code when the measured airflow is too high, too low, or otherwise not what it commanded. It is primarily an emissions issue and often traces to the air pump, valves, or their plumbing. Typical repair costs on Audi range from $80 to $1,400, depending on the specific model and root cause.
Common Causes of P0411
- •Failed secondary air injection pump
- •Stuck or faulty air switching/check valve
- •Carbon or moisture clogging the air passages
- •Leaking, cracked, or disconnected air hoses
- •Faulty pump relay or electrical wiring
- •Damaged or corroded connectors
- •Faulty vacuum control solenoid for the system
P0411 on Audi by Model
Audi A8(1 issue)
- Secondary Air Injection P0410/P0411 — Cracked Vacuum Lines, Stuck Combi Valves, Carbon-Clogged Head Ports1997-2003
The 4.2 V8 in the D2 A8 (both the early 32-valve ABZ and the later 40-valve AKB/AUX/AYS/BFM) runs a vacuum-operated secondary air injection system with one combi valve per cylinder head, fed by small-diameter hard plastic vacuum lines that become brittle with heat and crack. Both banks have their own combi valve, and it is usually the hard vacuum line that goes to them that breaks and causes a vacuum leak and inoperable SAI. Owners report replacing vacuum hoses and the SAI relay only to have the CEL return, and then having to look at replacing the SAI pump (SAIP), the solenoid on top of the engine, and replacing/cleaning out the combi valves aft of each cylinder head, which involves carbon buildup in the cylinder head ports. Symptom is a check-engine light shortly after a cold start with P0410 (or banked variants P0491/P0492).
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What does P0411 mean on Audi?▼
P0411 stands for "Secondary Air Injection System Incorrect Flow Detected." This emissions code means the secondary air injection system is flowing an incorrect amount of air. That system pumps fresh air into the exhaust shortly after a cold start to help the catalytic converter heat up and burn off pollutants faster. The computer monitors the resulting change in exhaust oxygen readings, and sets this code when the measured airflow is too high, too low, or otherwise not what it commanded. It is primarily an emissions issue and often traces to the air pump, valves, or their plumbing. On Audi specifically, this code is documented across 1 model.
What causes P0411 on Audi vehicles?▼
Common causes on Audi: Failed secondary air injection pump, Stuck or faulty air switching/check valve, Carbon or moisture clogging the air passages, Leaking, cracked, or disconnected air hoses, Faulty pump relay or electrical wiring. Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix P0411 on a Audi?▼
Repair costs on Audi range from $80 to $1,400, depending on the specific model and root cause.
Which Audi models have P0411 documented?▼
Au7o has documented P0411 on 1 Audi model: A8.