New some advice on EVAP.

[bprat318]

I have been battling a P0442 on my 2001 S10 for over a year now. I have replaced all the EVAP components with new OEM units (canister, purge valve and vent valve) and have checked on all the lines, no leaks. The interesting part about this code is that it only pops up when I am below half a tank of fuel, but not every time I get below half a tank, maybe every other time I get below half a tank it comes up. I was thinking maybe a Fuel Pressure Sensor is to blame? Looking for some possible explanations. I am really tempted to clear when it comes testing time and not really fix the issue.

 

[Trav]

Check the gas cap, use only an OEM unit. Check the filler neck tubes, hoses and clamps going to the tank, smoke test it

 

[bprat318]

Originally Posted By: Trav
Check the gas cap, use only an OEM unit. Check the filler neck tubes, hoses and clamps going to the tank, smoke test it


Forgot to mention, I did replace the cap as well, was actually the first thing I did. I checked the filler neck and associated hoses as well when I replace all the other parts and didn't see anything out of the ordinary.

 

[wirelessF]

OBDII EVAP readiness tests are done when the fuel level is between 1/4 and 3/4 tank, that't why the evap code pops up when it is at that fuel level. I fought with the EVAP readiness test showing up "Not Ready" despite meeting the conditions and doing many drive cycles. I had a bad fuel tank pressure sensor that came with an aftermarket fuel pump that did not throw any codes. Replaced the fuel pump with a Delphi unit and was able to quickly complete the EVAP readiness test the next day I completed the fuel pump install.

Then I found out I didn't have to replace the whole fuel pump unit, the sensor was just really snug and can be pried out. Make sure to replace it with a Delphi or ACDelco sensor.

 

[JustinH]

I know in New York and Texas you will pass a test with a certain amount of monitors being "not ready", so long as the check engine light is not lit.

I had a misfire code on my rav4 the day before it went in for inspection, I replaced the plugs and shut the code off. It showed not ready for evap.

When it comes to evap leaks you will need a smoke test to see what is leaking. You won't be able to see it usually. Just got done doing this with my brother's acura not too long ago.

 

[tomcat27]

in Illinois you can also pass with a "not ready" status. I just kept my tank above 3/4 tank.