I checked the voltage and it looks to be correct. .94 volts at idle, EGR closed.

While I was there I put a vacuum at 2.5 inHg and the voltage went to 3.2 volts which seems to be pretty right on.

Now I'm really stumped.

 

Code 334: EVP circuit above the closed limit of 0.67 volts.

Your test results indicate your closed voltage is 0.94 volts. There is the cause of your code.

That does not necessarily mean the EVP is bad. Many times the EGR valve pintle cannot fully close because of carbon build up on the seat. Inspect/clean the EGR before trying a replacement EVP.

 

Ahh, I didn't read it carefully. It's supposed to be between .24 and .67 with the EGR closed at idle for both the grey and black EVP. I looked at the chart and it says 0% should be .90 volts with a margin of error of +/-.2. I thought 0% would be a closed EGR at idle.

 

For a gray colored EVP the closed EGR voltage should be between 0.24 to 0.67 volts. It's easy to overlook.

 

The tech page doesn't say if those values are for a black or a grey. If that's for a grey, what is it for black?

I noticed when the EVP is installed the pintle is being pushed up a little by the EGR even when the truck is off. Maybe the EGR isn't closing all the way.

 

There is some preload on the EVP sensor, that is normal. That is another reason why it is hard to point the root cause at the EGR or the EVP. It is a process of elimination.

I have never had to deal with a black EVP, so I do not know what the closed values are nor do I care.

 

I figured for $30 I'd change the EVP and see what happens. Happy to report all codes are cleared. Thanks for the help.

 

Great news. Glad to see you got it fixed.

 

Good job!!!

 

I know im extremely late on this post but I was just wondering if this fix held up to what you said and never started doing that again?