I'm trying to diagnose a p0401. I had a p0405 previously but confirmed a bad EGR valve that was reading a sporadic.05 to.5v on pin C (supposed to be.6 to.9). However, after installing the new EGR valve I noticed that under operating conditions the signal voltage (letter C) does not increase when throttle is applied. It stays steady at.79v. I have 5v ref on D and 12v supply on E. Confirmed a good ground on B by unplugging EGR and testing for 12v between B and the battery+ terminal with key on engine off. I'm not sure how to safely test A. Which is the computer controlled ground I believe. If I back probe A and ground it to the body my signal voltage (C) does not increase. Shouldn't I be able to manually command EGR? Do I have a bad PCM or am I overlooking something?
Thank you for your time.
have the same problem?
Saturday, July 13th, 2019 AT 5:06 PM