I went to Checker auto and had my codes read because my "service engine light is on". My car runs good but when in reverse or pressing on the gas and going really slow (like through a drive through) it kind of chugs. I got 3 codes

1. P1640 - QDM 1 - Failure
2. P1670 - QDM 4 - Failure
3. P1406 - EGR Valve Pintle Position Circuit

Does anyone know what a QDM is??

I thinking of replacing my EGR Valve but its $155 and how knows if it will fix it...

Welcome to AF. Quad drivers are showing an overloaded circuit, whatever is in the those two quads is at fault, you will need a comprehensive wiring diagram for the pcm controls, but it may just be the egr is at fault here, disconnect it and clear the codes for test purposes, see what happens.

As Max said, you need to find out what items are being driven by the Quad Driver that set the code. This code usually sets when there is a voltage fault on a particular Quad Driver, due to a bad relay or solenoid, or whatever is being run off that driver. It could be a TCC solenoid, A/C relay, EGR, lots of possibilities, however, since you have code P1406 - EGR Valve Pintle Position Circuit, that helps to narrow it down somewhat. Before replacing parts, do as suggested, & check the wiring diagram for Quad Driver (QDM) 1 & 4.
Does anyone know what a QDM is??
The PCM controls most components with electronic switches that complete a ground circuit when turned on. When the switches are arranged in groups of 4, they can independently control up to 4 outputs and are called “Quad Driver Modules” (QDM). When the switches are arranged in groups of 7, they can independently control up to 7 outputs and are called Output Drivers.Hence the term “Output Driver Module” (ODM) Usually, not all the outputs are used.:rolleyes: