P0411 Fault Code

Long Description

Fault code P0411 is logged when the engine’s primary computer, the powertrain control module (PCM), has detected an issue with the secondary air system supply.

This occurs when the flow of secondary air does not match the expected flow determined by the PCM.

The secondary air injection system (SAIS) is used to pump ambient air into the vehicle’s exhaust system. This reduces the amount of unburned fuel that leaves the vehicle, particularly during cold start scenarios.

These systems were introduced in the ‘60s to reduce emissions as catalytic converters only reach operational temperatures after running the engine for some time.

These systems are typically only used in vehicles with petrol engines.

Audi, Chevrolet, and Volkswagen are some of the most commonly searched along with this fault code. Again, only petrol variants can suffer this error.

Other Signs of This Problem

It can be quite difficult to detect any signs of this fault code. The SAIS does not strongly affect the driveability of the vehicle, even when operating incorrectly. Any symptoms will typically be relegated to cold-start situations.

One of the best ways to help determine if there is an issue is the presence of the Check Engine light on the dashboard.

Then once you plug an OBD2 reader into the car’s port you find that this P0411 fault code appears.

The engine may idle roughly after a cold start. It may also suffer decreased performance like lack of acceleration and backfiring.

It is also likely that the exhaust fumes will be black, indicating that the engine is running rich.

There may be other fault codes logged that can indicate an issue with the SAIS. Look out for P0410 through to P0419.

What Could Be The Problem?

There are several components in the SAIS that could lead to this fault code being logged. Anything that can cause the flow in the SAIS to be reduced can lead to this issue.

A faulty check valve and cutoff valve, faulty air pump, defective air pump relay, or a failed management valve can also cause this issue.

Problems found within the circuitry could also be the cause. Things like loose connections and damaged wires will result in this type of fault code.

Additionally, leaks anywhere in the SAIS can cause this fault code to be logged. This can also occur through any clogging or restrictions in the lines.

Fixes

Depending on the cause of the problem, the fix can be electrical or mechanical in nature. It could also require new parts.

Any defective parts need to be fixed or replaced. Along with the air pump, the valves and their solenoids are particularly likely to need to be fixed. Faulty sensors should also be replaced.

Damaged wiring or loose connections need to be fixed as well. These can be from the valves and sensors.

The system should be cleaned of any carbon buildup. Any leaks should also be fixed accordingly.

Seriousness

Fault code P0411 should be considered low in terms of seriousness. It does not pose any issue to the driveability of the vehicle or risk to the components.

It is a good idea to have this fault fixed within a few weeks as the car will likely fail an emissions test.