P0411 Chevrolet -

Question

just replaced secondary air check valve still getting code po411 incorrect air flow upstream I think it was. Had 4 codes before installing the valve now only 2, po411 is the only one I can see. CEL was on before install but haven't driving it yet to reset the monitors.

Answer 1

Hi there,

This code indicates an issue with the secondary air injection system. Here is a list of possible causes. 

P0411 CHEVROLET - Secondary Air Injection System Insufficient Flow

Read more: https://www.autocodes.com/p0411_chevrolet.html