keep getting this code, scanner says" evaporative emission vent control circuit malfunction" have checked the valve and connections under the backend near the spare, took apart the box and filter and cleaned it good, checked the gas cap, dont know what else it could be. doesnt affect driveability, just comes on every so often, sometimes once a week, sometimes every other week. dont know what it could be, ive thoguht about disconnecting that vent valve and seeing what happens. if i dont clear the code with my scantool it will sometimes dissapear after a while. i usually just clear it because the ses light bothers my wife (she thinks its some bigger issue) if it wasnt for other issues that could come up, id just do what i did with the astro and take apart the dash and tape over the light with black electrical tape. the '95 parts blazer i have access to doesnt have the same vent valve underneath, they both do have the charcoal canister behind the l.r. tire. the '95 is a different engine code, its a multiport f.i., but the '97 has the spider f.i. system. could it be something other than that vent valve? im not getting any vaccum or pressure when taking off the fuel cap to refuel. i do seem to get a vaccum noise/feel when refueing the ranger if its real low on fuel and i refuel. (probly not related, just a observation) anyone else run into this situation before?

 

On my Jimmy, I believe it was this code I was throwing. replaced vent valve and it didn't do anything...

Check the wire in the loom that ran over your front drive shaft, when the dealership replaced the transmission in mine they didn't hang these up properly and ended up touching the front shaft and wore through the wire.

I believe you should always have power back there and the ground is switched in the computer when it wants it to open, you need a good Scan tool to force it to open or close to test the wiring properly.

 

this should help

https://blazerforum.com/forum/diagno...plained-35143/