Code P440 on 2001 Jimmy

Every 4 or 5 days for the past 3 or so weeks, I've been getting an SES light. It's always a result of a P440 code (Evaporative Emission Control Malfunction).

I clear the code, and everything is fine for 4 or 5 more days. The SES light usually only appears (and then stays on) when I start the truck. (I haven't seen it come on while actually driving) The truck appears to be running well, and if not for the SES, I wouldn't suspect a thing wrong. (Except for the wonky gas guage, as posted in another thread...)

Any suggestions as to what I might have a look at? I'm a fairly decent "home mechanic" but what I know about emission control systems you could fit in a thimble (and have room left over for everything I know about nuclear physics...) :-)

Any help would be appreciated.

Dodger

Every 4 or 5 days for the past 3 or so weeks, I've been getting an SES light. It's always a result of a P440 code (Evaporative Emission Control Malfunction).

I clear the code, and everything is fine for 4 or 5 more days. The SES light usually only appears (and then stays on) when I start the truck. (I haven't seen it come on while actually driving) The truck appears to be running well, and if not for the SES, I wouldn't suspect a thing wrong. (Except for the wonky gas guage, as posted in another thread...)

Any suggestions as to what I might have a look at? I'm a fairly decent "home mechanic" but what I know about emission control systems you could fit in a thimble (and have room left over for everything I know about nuclear physics...) :-)

Any help would be appreciated.

Dodger

P0440 is a large leak in the EVAP system (usually caused by the gas cap being left loose)..but, if you keep clearing the light and it comes back, that means there is a problem (clearing the light does not fix the problem)
My suggestion is to have the EVAP system tested to find the source of the leak so the proper repair is made.

Look for an EVAP leak in your lines going from your AC routing by the radiator

I am currently having this same problem however with my jimmy but i erased the code and it was gone for months then reappered now its on and off every couple days for the last 2 weeks. Checked the gas cap and no problems with it so wondering where to go next

I am currently having this same problem however with my jimmy but i erased the code and it was gone for months then reappered now its on and off every couple days for the last 2 weeks. Checked the gas cap and no problems with it so wondering where to go next
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