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Repost, 440 Fault, 6.0l 1999 Chevy 2500

LowRyter

By LowRyter
in Ask A GM Technician

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LowRyter Enthusiast

LowRyter

Posted
Posted

I got a service engine light. Code reader listed 440:

 

Evaporative Emission System (EVAP) small leak/no flow condition

Probable Causes:

a) Defective or loose fuel cap

b) EVAP Canister or hose cracked- not connected

c) Purge or vent solenoid defective

d) Vacuum leak at engine.

 

I was driving, light came on, half tank of fuel. Open & closed the gas cap; looked under hood, couldn't hear leaks of see anything amiss. Truck has 82k miles.

 

Is there a good place to start here? (It doesn't look critical from my perspective.)

 

I don't like the warning light on.

 

thanks

atboley Enthusiast

atboley

Posted
Posted

ok, lookit, the most common cause i see for that code(which BTW is the problem 75% of the time), is a bad gas cap... THEY LEAK!! if you want to throw darts, replace the gas cap and clear the code and see if it resets, most likely thats your problem... and dont buy one of those cheap locking gas caps from pep boys, or whatever auto parts store you go to, you would be better off with a rag stuffed in there.. otherwise you would have to take it somwhere that could smoke test it to see exactly where the leak is comming from... very rarely the purge solinode will stick open and leak, but that will normally set a diferent code... the charcoal canister very very rarely will have a line that comes loose, but i wouldnt even bother checking it, waste of time... check and make sure your filler neck is tight at the tank, somtimes that will cause a leak...

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