I have a Orange light on to the left top side. The next 2 are red for battery and oil I think.

What is that symbol and what is wrong?

I did oil and filter change yesterday and also took the battery out to install a headlight bulb.

 

I did some research and found :

OBD Indicator – member of the Onboard Diagnostics, this indicators reveals a problem to the engine or to the gas emissions and required the car to be serviced.

What can we wrong though?

 

You should get an OBD 2 scanner (around $20 from amazon.com) and get the error code then post it here... Or you could go to the local Autozone store or advancedautoparts store to borrow their scanner. I'd say just get the scanner since you're probably gonna need it often from now on, and it's nice to see the error code for yourself.

 

Is it something major? What could be wrong? Low oil?

 

Since you took the battery out and re-installed it, it may have to do with the battery not held firmly in place. A little bump may have cause an electrical gremlin and the malfunction indicator light to come on. Disconnect the battery and make sure the battery is held firmly in place; but, don't over-tighten the nuts to the hold-down bolts. Give it a good nudge to see if the battery moves.

By disconnect the battery and re-connecting, the ECM/PCM should reset. If the malfunction indicator light comes back on, then get the trouble code read to narrow down the problem.

 

As accordhybrid owner said, it really could be anything. If you are not mechanically inclined or dont work on your car, take it to a repair shop. If you like to do the work yourself, drive it to the nearest autozone and have them run an OBD II scanner. Make sure you write down the code. If you have a Haynes manual, you can then look up the code. If you dont, you can always try to do a google search. But as a caution, I would try to drive as absolutely little as possible until you have the code read and learn what the cause is. Just my $0.02 worth

 

What if I don't do anything?

 

Could it be low oil? What else can it be?

 

The car can be driven normally if the light is steady (not blinking) and just on; but, you should get the trouble code read if the malfunction indicator light (MIL) remains.

Generally, if a fault is detected in two consecutive drive cycles, then the MIL will come on. If in subsequent drive cycles, and the fault is not detected, the light may go off.

If the light is blinking, then the car shouldn't be driven, as this can cause engine damage. If it is blinking, then get it checked ASAP.

 

Definitely get the error code before anything else...