KevinTernes

I recently removed AIR and valve covers to inspect my rocker arms (that's another thread, though). I ended up retorqing them. No problem.

When I put everything back together, I neglected to tighten the passenger side AIR pipe before starting the car. <img border="0" title="" alt="[Roll Eyes]" src="images/icons/rolleyes.gif" /> Anyway, I quickly corrected that.

But now I have an SES code that will not clear. I replaced the AIR pipe gaskets. It still would not clear.

Then I had the code read:
P0405 - EGR Position Sensor Circuit Low Voltage

The thing is, I never touched the EGR. It looks okay on the outside. I disconnected the wiring harness and cleaned the contacts. Code still won't clear.

I am going to pull the EGR off to inspect and clean it this weekend. But I don't really know what I am looking for.

Any ideas? Could the fact that I left the AIR pipe loose have damaged the EGR?

Thanks!

eallanboggs

iTrader: (1)

EGR has these code: 1)Insufficient flow. This means the EGR is not opening to allow flow. 2)Excess flow. This means the solenoid is stuck open either electrically or mechanically causing flow when there should not be any flow. 3)No solenoid activity. This means the EGR value does not open when the PCM commands it to open. This is the problem you have. No 5vdc getting to the EGR or the EGR solenoid is OPEN so it wouldn't activate even if the 5vdc got there when it was supposed to. P0405 is Pintle Position Low Voltage. That's the 5vdc line. You need to find 5vdc on the connector that goes to the EGR valve from the VCM. I'm looking at the GM shop manual for you and it looks like a BRN wire. The BRN wire is called EGR pintle position signal and the WHT wire is EGR valve ground. You need to check for continuity on the EGR valve itself to be sure the solenoid is not open and look for 5vdc on the
BRN wire. Problem is the PCM has to command the EGR to open for the 5vdc to be present at the BRN wire. The only way to do that is with a bi-directional scan tool which I doubt you have. You'll have to read the GM shop manual to find out when the PCM runs the EGR monitor so you can check for the 5vdc at that time or you can buy a Tech 2 scan tool for $2000.00 to turn the EGR on anytime you want. You should also check to be sure the signal line is not shorted to ground at the BRN wire on the connector and that the EGR is not shorted to ground on either the BRN or WHT terminal. The manual says check for this, but I say that if you have a short to ground you should have blown a fuse by now. Check all your fuses to be sure none are blown. If a fuse is blown your on the right track. If it blows again when you put in a new fuse GO FISH because you really DO have a short to ground somewhere. It's that simple.