Beeping noise from behind left rear tire

Hi,

My wife has a 2002 grand cherokee laredo, V-8. The engine light is on. Took it to the shop and they said that the computer told them there was a large evaporative systems leak. Mechanic told me gas cap was loose even though I told him the light had been on for a month. The car runs fine. However on occasion I have noticed a beeping noise when I am outside the car and the car is idling. It is coming from the area of the canisters that are located directly behind the left rear tire. I told the mechanic this, he thought I was smoking something funny. Any idea what the deal is?

Thanks,
Cole

I'm having the same problem with my 2003 grand cherokee. Anyone have a suggestion?

Yes, I suggest you post this in the GRAND Cherokee forum. They are more familiar with those systems than most folks here in XJ land (unless they own a GC too). :)

Moved to GC forum.