apparently, in virginia, the emissions are now done for 96 and newer trucks are done only by reading the OBD2 information. this is bad for me becuase the code for the EGR valve always pops up. SO...I failed this time. The guy at the shop suggested that the sensor is bad and that was a cheap thing to replace to try and solve the problem. He also suggested that they do diagnostics. I said no thanks, politely. i will keep my money and fix it myself. Further back info. the truck has a new EGR valve, replaced about 6 months ago.

Im about to go and pick up a sensor for the vavle, but i am wondering if there is anything even cheaper that i can do first. ????Ive heard taht there is some hoses that i could clean or replace?????? Thanks for the help with this one, its been bothering me for a long time.

The truck is a 96 with all of the goodies if that helps. Thanks

 

Hey 96eddie, I had trouble with my egr about a year ago, If im not mistaken the valve was mor expensive than the sensor and harder to replace. After replacing the egr I found out that it was the sensor after all. But that was just with mine I did have some cracked tubing going to my sensor, that wasnt the problem but it could be worth checking. Btw if you have a code reader you could just clear the codes b4 you go for inspections. Just do the right thing and find/fix what aills your truck.

 

Make abosultely certain the plastic vacuum line to the EGR valve is intact and connected. They get very brittle with age and can snap during normal operation if they are brittle enough.

The EVP sensor moves ONLY when the EGR valve moves. If the valve is sticking the sensor takes this as an incorrect reading. The EVP sensor is a variable resistance sensor and over time will experience a change in resistance value by virtue of that age. The sensor can also develope "dead spots" which will send erroneous info. to the computer.

You can also remove the EGR valve and clean it as well. Some throttle body cleaner and the little scrubbing will get most of the crud that builds up on it. Take extra caution not to damage the vacuum diaphram and make certain the pintle seats fully before re-installing the valve.

 

i went out and bought a new sensor. what is the best way get the hoses off of the bottom of the sensor? thanks

wiggle and twist worked, i just didnt want to break or crack them. now its time to see if the computer accepts the change and the codes go away.

 

Make sure you disconnect the battery for at least 5-10 minutes before you pull the codes again after the replacement. This will clear the stored codes from the memory.

 

thanks for the reminder, i actually remembered on the way home from work today because i was getting mad that the light wasnt turning off..

thanks, ill post how it all turns out

 

darn it all. replaced the egr and the sensor and the light came back on.
codes read:
P0401 Exhaust Gas Recirculatoin Flow Insufficient Detected

im at the end of the rope here. any ideas. thanks

 

So now its time to check the wiring to the sensor itself and the vacuum to the valve. It may be the the EGR valve is not getting the necessary vacuum. There is an air solenoid called the EVR that controls the vacuum supply to the EGR valve. It has a small filter atop to prevent crud from entering it. (You can find it by tracing the vacuum line at the EGR valve back). If you have no vacuum at the EGR valve, the EVR may be the culprit. Again check for loose connectors or broken wires as well.