[cardoc]

In the past, with all manufacturers, the "check engine light" would come on and be ignored by the owners. "It's just a sensor". A sensor that manages the operation of the drivetrain in some form, regardless of how small the owner feels about it's importance for performance and emissions, has a problem and it dominos into something worse than poor operation or management. This in turn created issues with warranty coverages, cost of repairs and overall life of the drivetrain components. The "fix" was to light up the dashboard to get your attention, and it works. It got your attention.

On top of that, all of the various systems on the car work in conjunction with each other to manage the things people wanted, and even what governments mandated, on/in a car. Lane departure for those that don't pay attention when they drive uses the brakes and electric steering to maintain lane direction. Emergency/automatic braking for the same reason. Radar cruise control, Eyesight, radar blindspot monitoring and others. The stability and traction systems use the engine, trans, brakes and steering to maintain an upright position for the car. When something in any one of these systems has a fault, all the systems are affected and each system gives you the fault it is experiencing. Most times it's a single element creating issues with multiple computers.

It may be a loose gas cap. It could be a weak battery or issue with the charging system and electrical components on the car in any or all systems are unable to function properly. It could be low engine oil and the engine performance is suffering because valve management isn't working as it should.

The warning lights are there to get your attention, things shut down due to faults and the lights are telling you this. It's simple - get all the systems scanned to see what the fault may be and get the fault corrected, whether it's a low battery, loose gas cap, or the oil is low, it's all pertinent to the proper function of the whole car and managing performance in conjunction with emissions.

Subaru is not the only company that this occurs with the cars and warnings. Especially when alot of electrical parts are involved in the operation.

 

[cardoc]

Yes. EVAP monitors run over time. There's a "soak" period where it determines if there is a leak based on tank pressures. It watches pressure while driving. It does things to pull a vacuum and release it. All the time watching for issues.

 

[cardoc]

Thanks for your answer - one more if I may. I did check for error codes and got 8 of them - see attached. Does it seem reasonable that all the codes could be related to a gas cap? It is my daughter's car and just trying to do my best to fix it for fear of her getting into trouble on the road.

View attachment 522697

Art

All those codes are electrical related; "Circuit".

Back to checking the battery ampere output and the cables for excess corrosion. Not voltage, amperes. That is checked with the engine off and all the accessories off and best if after the car is set for about an hour and the battery has cooled off. Shops that know have a tester in their toolboxes. You may be able to go by an O'Reilly's Auto Parts and ask them to check the Ampere output of your battery because they sell the midtronics pbt series tester. They can also check your alternator output after checking the battery output.

If the battery cables are bad you have to get those from Subaru. And since the positive clamp has more than one cable attached to it you have to get the clamp for the positive cables separate from the cable set.