: 1998 STS Trouble Codes & Emission Test

05-12-13, 02:27 PM
What's up fellas. I'm on my second 7 day permit to drive on while I try to pass emissons test. I've reset the computer since I had the car the past year atleast 20 times just to et the engine light out. However I know that doesn't fix the problem. I have about 3 codes that are current. I'm not around the vehicle right now so bare with me.....the engine light pops on & I get P0440(EVAP) along with "Check Gas Cap"
Another code I believe is for the speed sensor.
And another is for the door vent actuators. I will post those other 2 exact codes but the one that concerns me is P0440 & check gas cap. Those maybe preventing me frm passin emissions. Help anyone please?

05-12-13, 03:05 PM
It's the P codes that will cause you to fail the emissions test. P0440 is telling you that you have a vacuum leak in the EVAP system. A bad or poorly seated gas cap is a common cause, hence the "Gas Cap" message. Check all the lines and fittings.


05-12-13, 03:06 PM
ANY EVAP code will fail an emissions test. EVAP is the system that stores fuel vapor from the fuel in the gas tank expansion/contraction due to heat/cold. The system uses sensors, solenoids, lines, and a charcoal canister to store vapor until the engine is warmed up and at some steady cruise operating condition - then the EVAP syatem purges the charcoal canister with fresh air, burning the stored fuel vapor in the process.

The problem can be with a gas cap, filler neck, vacuum lines, canister, solenoids, or pressure sensor(s). P 0440 says that you have an air/vacuum leak into the sealed system - somewhere.

Oooopppppssss........... Ranger beat me.