po440

[scotto0609]

so for the last year or so i have been getting a random 440 code that i just reset and then goes away for about a tank or 2 of gas on the suburban. This January i put a higher test octane in the truck that has avoided the light. however i forgot and the light is back on after a tank of regular. Any ideas why the octane would cause the difference in parameters? thanks scott

 

[east302]

Not sure why the octane would matter. The code is for the evaporative emissions system, it takes vapors from the fuel tank and stores them for later introduction into the combustion cycle.

Start with the gas cap, but also check for any damaged lines into and out of the evap canister. Much more than that is going to require a scan tool to diagnose.


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