SureTrack Community Fix: Gas Cap Message

Real Fixes from ShopKey’s SureTrack® expert information resource are documented issues from actual shop repair orders and community discussions. Read on to see how SureTrack can help you correct issues that are not easily diagnosed using OEM information alone. SureTrack is currently available free with the purchase of a current Snap-on® diagnostic software version or in our ShopKey Pro product.


Have you ever wondered why newer vehicles have a Gas Cap message or light on the instrument panel? Because of tight evaporative emissions standards, a loose gas cap could cause the check engine light to come on. Owners would bring their vehicle to the dealer for this simple problem when they could have fixed it themselves. It cost the dealers both money and customer satisfaction. But when the gas cap isn’t the problem, you still need to find the fix. SureTrack community member mtbittinger had a 2012 Dodge Grand Caravan in the shop that had the gas cap message coming up soon after starting even though the cap had been replaced more than once. They posed the question to the community, and with the help of fellow community member ericsautomotive and others, they were able to resolve the issue quickly.

The following Community Fix summarizes the interaction between members of the community that led to the solution.

Vehicle
2012 Dodge Grand Caravan SE 3.6L

Title
Gas cap message, replaced ESIM.

Complaint
Customer complains that Gas Cap message appears after starting vehicle.

Diagnostic Steps Performed/Parts Replaced
Gas cap message comes up a few seconds after starting the vehicle. Checked for codes and found P0456, small EVAP leak.
I had the smoke machine hooked up but my scan tool gives me no option to close the vent and/or purge valves. I plugged the outlet side of the vent valve and there are no leaks. The customer, which is a fleet shop, has replaced the cap with an aftermarket cap, and then an OEM cap but still get the same message.

Best Answer from Community Member ericsautomotive
Evaporative System Integrity Monitor (ESIM) failures are so common on these. I’m using old ones for freaking door stops in my shop!!

Cause
Faulty Evaporative System Integrity Monitor (ESIM)

Correction
Replaced Evaporative System Integrity Monitor (ESIM) and Gas Cap message did not come back.


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About the Author

Nick Taylor

Nick Taylor is the SureTrack Community Administrator and a Senior Applications Specialist at Mitchell 1 with over 25 years of experience with electronic repair data systems. Nick previously worked in the automotive dismantling and engine rebuilding industries.