Engine light came on

Please them the time to read your question. Some of us are only here a few hours per day, so it can be hours before someone replies who feels confident they can see this through to a solution. Since I posted this reply, unlike in other forums where anyone can chime in and confuse the issue, this has become a private conversation between the two of us. As such, the experts who specialize in engine performance problems are not going to see this or have a chance to reply. That may not get you the help you need. I would suggest reposting your question, but if you expect someone to take the time to write up a response, you are going to have to provide some details. Since this is an engine-related question, you have to at least list the correct engine size. Most models use wildly different ignition, fuel, and emissions systems with different engines. We also need to know the engine size and transmission type when searching for the correct diagrams and photos to post. We even look at the mileage when suggesting the best suspects.

If this is the Check Engine light you're referring to, the first thing your expert is going to ask is what diagnostic fault code number was set. Most people don't have their own code reader. The people at most auto parts stores will read them for you for free, but be aware, they are in the business of selling parts. No fault code ever says to replace a part or that one is defective. They only indicate the circuit or system that needs further diagnosis, or the unacceptable operating condition. When a part is referenced in a fault code, it is actually the cause of that code about half of the time. First we have to rule out wiring and connector terminal problems, and mechanical problems associated with that part.

Once you know the fault code number, you may be able to find the definition on this list:

https://www.2carpros.com/trouble_codes/obd2/p0700

Don't worry if they don't make sense. We're here to interpret them for you and develop the best course of action. Due to the age of your vehicle, the list of possible fault codes is even longer, and many are brand or model-specific. We have other resources for finding the definitions for those.

Your expert will also want to know when this warning light turns on or if it stays on all the time. Any other details or observations can provide clues that help us figure this out faster.

If it will save you time, here's the link to post your new question:

https://www.2carpros.com/questions/new

Start with having the diagnostic fault codes read and recorded. Back before the mid 1980's, all we had to check was the fuel supply system and the ignition system. If those worked, the engine would run. Since then, there's just way too many circuits to check individually. It could take days to figure out what is wrong. Instead, your Engine Computer takes care of that for us. To add to the misery, your Engine Computer can detect over a thousand different defects that you would never be aware of. Most of those involve the exhaust / emissions systems. Your engine could be using excessive fuel or the emissions system is letting too much bad stuff to go out the tail pipe. Those are things you'd never notice if it wasn't for the computer that detected the problem, set the fault code, and turned the warning light on tell you. The computer runs continuous checks on most of the circuits while you're driving. A few special tests are run only when the right set of conditions are met, such as sustained highway-speed driving for a certain number of minutes, and things like that.

Be aware too that many of the things that get detected by the computer are pretty minor, or it can be an inexpensive problem that results in a lot of pollution. Something as simple as a loose gas cap can let fuel vapors escape from the tank. Dry-rotted rubber hoses and rusted hose clamps are more examples of inexpensive causes, although many of those are almost impossible to find without special equipment.

Thinking of some other brands of hybrids, problems can be caused by using the wrong engine oil or not having it changed often enough. Those are things you'll need a hybrid specialist for. That applies to a lot of our other experts. The majority of the diagnostic fault codes apply to all car models, but there are some that only apply to hybrids.

I'll be back tomorrow. If I can find your new question, I'll follow it to see how this turns out. One of my specialty areas is electrical. Sometimes I'm asked to join the conversation when my wondrous expertise is needed, otherwise I'll just sit on the sidelines to see what I can learn.

There's three engines that were available in your model and year, the 2.4L four-cylinder, and the 3.5L and 3.6L V-6s. Only the 2.4L is also listed as optional "electric/gas", so we know you have a 2.4L engine. Your expert will be able to figure that out.