my emission light came on suddenly
Emissions systems are complex, many functions. So there a number of different possible causes. To narrow it down, ask your shop to read the computer’s diagnostic codes. You are welcome to post the code numbers here, you’ll likely get some more ideas here. Typical diagnostic code format is a “P” followed by a 4 digit number, for example P0420.
Did you expect it to come on slowly?
Sorry to hear of your warning light Genela. The chances are very good that it is caused by a simple gas-cap-related issue. The first thing to do is check that it is securely tightened. If it is, it could be a cap with a crack to a faulty seal - a very inexpensive repair. If not, remember your vehicle has a VERY long emissions control equipment warranty. Here is some background on things of this nature from Car Talk: Most Common Causes of the Check Engine Light - Car Talk
IIRC, that warranty is for 8 years/80k miles. If the OP’s odometer mileage is less than 80k, simply take it to a dealership for no-cost repairs.
If you want us to help you, take your Ridgeline to an auto parts store like Advance, Autozone, or O’Reilly’s. Call ahead to make sure they have an OBD-2 tester that works, then drive over and they will run the test. Take a picture of the codes with your phone and post them here. We can help you sort them out. If you prefer, you can take your pickup to a mechanic you trust, of course. BTW, how many miles are on this Ridgeline?
That’s usually how it happens.
The Federal emission warranty provided by Honda is the same as many other manufactures; 3 years/36,000 miles. Only the PCM and catalytic converters are required to be covered for 8 years/80,000 miles.
What do you mean by “emissions light”? The check engine light? If so, get your codes read and let us know what they are.