EGR ECM EO65 error code

[My Youth]

On my 1990 Reatta, I recently replaced the EGR valve assembly and am getting the EO65 error.  The code indicates a "large" EGR error. One is history and one is current.  Should I reset the codes and see if it persists?  What is the difference between small, medium, and large EGR error codes.    The car was running rough at cold  idle and would die under load.  It would restart and once up to temp it seemed to run okay.  It would backfire some before it warmed up.  Seems to be running okay but getting the "service engine" light on the dash. 

[Ronnie]

Welcome to the forum!

 

1 hour ago, My Youth said:

What is the difference between small, medium, and large EGR error codes.

The EGR valve has three separate openings inside that are controlled independently by the ECM.  I would check to make sure the EGR making a good electrical connection, then clear the codes and see if any come back.

[2seater]

Just to amplify what Ronnie said: the three openings are also different sizes, small through large, relatively speaking.

You could try tapping on the solenoids to see if it helps the idle. It sounds like a pintle is stuck open if the rough idle/stall is a current problem. You can also go to overrides and cycle the individual solenoids to see if that helps free up the valves. It could also be a chunk of carbon holding it open.

Edited August 21, 2023 by 2seater