can a bad idle air control valve cause a code p0402 egr circuit malfunction

Question

I don't understand the above

Answer 1

HI there,

Although this code isn't coming up in the service manual for the car, the P0402 code will not happen because of a bad IAC. However, if the egr valve is sticking open it can cause idle issues which would make you think the IAC is the problem.

This code indicates that the egr might be sticking open or the tube to the egr valve may be blocked up with carbon. It could just be that the egr has failed as well. What I would do is remove the egr and clean it up with some carb cleaner and check the tube to the egr. Make sure it's not blocked.