EGR Valve-99GTP

Hello everyone, I am new to the forum and thank you in advance for your help! My SEL has been coming on and off now for about two months. Recently here for the past week it has stayed on permanantly. I went and had it hooked up to a scanner and it popped out code P0405...EGR system fault. Can someone explain to me this code please and wether or not i can clean it or how to tell if it is stuck. They are expensive to replace and i would love to be able to repair it myself. Thanks, Brandon.

P0405 DTC indicates that the EGR valve position sensor circuit has low voltage so it is probably more electrical than a mechanical issue with the EGR. Diagnostics has detected the pintle position feedback circuit is either open or shorted to ground. You can try cleaning the mechanical part of the EGR valve but it probably won't do much good.

Also, check the electrical connector to the EGR for any bad wires or flaky connector.

And welcome to the forum and AF.

i will do that. more than likely tho i will need to replace it is what your saying. thanks

more than likely tho i will need to replace it is what your saying. thanks

Basically...correct.

You could check the PCM 5 volt reference signal at the EGR connector input and then the pintle output to see if it is shorted or grounded on top of what was suggested just to be sure. EGR valves are not cheap.

So i went and bout a new egr valve(175.00). I installed it and reset my computer by disconnecting the negative battery terminal. Waited about 15 minutes and hooked the cable back up, got in my car and started it. Sure enough the SEL was still on...any idea as to where to go from now?

Disconnecting the battery negative will not clear that DTC and the SES/CEL light. You need an odb-ii scan tool/scanner to properly reset a PCM module. Other option is to drive it for a few drive cycles and then see if it clears when the PCM runs the EGR test.

Disconnecting the battery negative will not clear that DTC and the SES/CEL light. You need an odb-ii scan tool/scanner to properly reset a PCM module. Other option is to drive it for a few drive cycles and then see if it clears when the PCM runs the EGR test.


That is EXACTLY what I had to do with mine a few months ago and I've had no problems ever since.