Secondary air injection system incorrect flow detected — Diagnose and fix

Secondary air faults are common on older vehicles equipped with a secondary air system. You may be alerted to a secondary air problem by any one of the following trouble codes:

P0410 Secondary Air Injection System Malfunction
P0411 Secondary Air Injection System Incorrect Flow Detected
P0412 Secondary Air Injection System Switching Valve A Circuit Malfunction
P0413 Secondary Air Injection System Switching Valve A Circuit Open
P0414 Secondary Air Injection System Switching Valve A Circuit Shorted
P0415 Secondary Air Injection System Switching Valve B Circuit Malfunction
P0416 Secondary Air Injection System Switching Valve B Circuit Open
P0417 Secondary Air Injection System Switching Valve B Circuit Shorted
P0418 Secondary Air Injection System Relay A Circuit Malfunction
P0419 Secondary Air Injection System Relay B Circuit Malfunction

The most common code is P0411

See this post to learn what the secondary air system does and how it works.

Most common cause of secondary air incorrect flow

Secondary air is added to the exhaust manifold or directly into the catalytic converter mainly to add oxygen to the exhaust to complete combustion of excess fuel and to get the catalytic converter up to full operating temperature.

The ECU commands the A.I.R. pump to run and energizes the secondary air solenoid valve to open to allow air into the exhaust. It then expects to see a leaner report from the upstream oxygen sensor to confirm that air has been added to the exhaust.

If it doesn’t see an increase in oxygen, it sets a secondary air incorrect flow trouble code.

There are two common causes of secondary air incorrect flow

1) Failed switching valve that’s not opening
2) Failed A.I.R. pump

A failed switching valve is the most common

Secondary air one-way valve and solenoid

cause of this problem. Check the switching valve to make sure it’s opening when commanded.

If you have a bidirectional scan tool, you can command the A.I.R. pump on to check operation. If you don’t, you’ll have to use jumper wires to add power and ground. If the A.I.R. pump doesn’t work, that must be fixed first with a new pump.

Electric Air Injection Reaction pump

©, 2023 Rick Muscoplat

Posted on March 28, 2023 by Rick Muscoplat