Northstar Engines and System Technical Discussion Discussion, 1998 STS Trouble Codes & Emission Test in Cadillac Engine Discussion; What's up fellas. I'm on my second 7 day permit to drive on while I try to pass emissons test. ...
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?
Automobile(s): White Diamond '03 DHS (with DTS floor shift)
Re: 1998 STS Trouble Codes & Emission Test
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.
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.