We only handle one problem per thread, and it sounds like the heater problem is separate from the EGR code issue so that is what will concentrate on with this thread, please start a new question for the heater issue.
P0400 - Exhaust Gas Recirculation Flow Malfunction: This code indicates that there is a problem with the flow of exhaust gas recirculation in the EGR system.
P0403 - Exhaust Gas Recirculation Control Circuit: This code points to an issue with the electrical circuitry of the EGR system, specifically the control circuit.
So, if you already replaced the EGR valve it sounds like you have a bad connection for the EGR to the PCM. Here is a guide to help and the EGR and engine wiring diagrams so you can see which wires to test with the guide:
https://www.2carpros.com/articles/how-to-check-wiring
The wires at the connector look like they may be broken. Check out the images (below). Let us know what happens and please upload pictures or videos of the problem so we can see what's going on.
Images (Click to make bigger)
SPONSORED LINKS
Thursday, September 21st, 2023 AT 12:38 PM