The engine light icon came on. I checked all fluid levels and topped them off and light is still on. What else could it be?

When the brake booster light and brake light come on after replacing the batteries in a 2017 Isuzu NPR Diesel, it could indicate a problem with the brake system or a malfunctioning brake booster.
Here are some steps you can take to troubleshoot the issue:

1. Check the brake fluid level: Low brake fluid level can cause the brake booster light and brake light to come on. Open the hood and check the brake fluid level in the reservoir. If the level is low, top it up with the recommended brake fluid and check if the lights go off.
2. Check the brake system: Inspect the brake lines, brake pads, and brake rotors for any damage or wear. If the brake pads are worn out, replace them immediately.
3. Check the brake booster: The brake booster is responsible for increasing the force applied to the brake pedal. Check the brake booster for any damage or wear. If the brake booster is malfunctioning, it will need to be replaced.
4. Reset the brake booster light: If the brake booster light and brake light stay on even after checking the brake fluid level and inspecting the brake system, it may be necessary to reset the brake booster light. To reset the brake booster light, turn the ignition switch to the "on" position without starting the engine. Pump the brake pedal 3 times, then turn the ignition switch off. Start the engine and check if the lights go off.

If none of these steps work, it is recommended to take the vehicle to a certified mechanic or the nearest Isuzu dealership for a professional diagnosis and repair.

Is the yellow light a plain dot with no shapes or signs on it? If it is and it is on the fuel level gauge it is most likely a 'Low Fuel' warning light. Filling the fuel tank past a quarter tank should turn this light off.
For the steering check the steering fluid level. A low level makes the steering harder to turn as there is not enough fluid in the system to work properly. Top the fluid up to the correct 'Max' mark and bleed the system. To bleed the system is really easy. Start the engine and turn the steering all the way to the left then all the way to the right. Do this 3 or 4 times. Turn the engine off and re-check the steering fluid level.
The oil leak could be something more serious so I will need more information to help you. First check your oil level with the dipstick. It should be between the two marks on the stick. Too much oil in the engine can cause other problems.
Where EXACTLY is the oil spilling out? Is it from the filler hole and cap you pour the oil into when your topping it up? Is it the bigger, long cover on top of the engine that the oil filler cap is fitted into? Comment below an I'll see if I can help you more.

Have you checked all of your fluid levels? on the check engine I would have it hooked up to a computer to give you a code. it could just be your fluid levels. it is possible for it to be interconnected. good luck

LISTEN FOR HYDRALIC PUMP MOTOR OPERATION IN THE TRUNK AREA..IF YES YOU HEAR HYDRALIC PUMP MOTOR RUNNING MAKING A NOISE.CHECK HYDRALIC PUMP FLUID LEVEL BY REMOVING THE SCREW TYPE CHECK PLUG.PLACE RAGS UNDER THE CHECK PLUG.AND UNSCREW REMOVE THE CHECK PLUG. FLUID SHOULD BE 1/4 INCH BELOW THE CHECK PLUG HOLE.IF FLUID IS LOW ADD FLUID UNTIL FLUID LEVEL 1/4 INCH FROM THE PLUG HOLE.IF HYDRALIC FLUID WAS WAY LOW YOU NEED TO BLEED AIR OUT OF THE SYSTEM.MAKE SURE FLUID LEVEL CORRECT.START ENGINE AND TRY RAISING AND LOWER THE CONVERTIBLE TOP USING THE SWITCH.IF TOO MUCH AIR GOT IN SYSTEM.HAVE A HELPER WORK UP AND DOWN CONTROL SWITCH WHILE YOU MANUAL OPEN CLOSE CONVERTIBLE TOP BY HANDS BLEEDING AIR OUT OF SYSTEM.KEEP EYE ON HYDRALIC FLUID LEVEL WHILE BLEEDING THE SYSTEM..LOWER THE TOP AND TURN OFF ENGINE. BEFORE OPENING THE HYDRALIC PUMP FLUID CHECK PLUG BECAUSE FLUID WILL SPRAY EVERY WHERE..IF HYDRALIC PUMP CHECK OUT OKAY AND YOU DO NOT HEAR NO HYDRALIC PUMP NOISE.POWER IS GOING TO HYDRALIC PUMP.EITHER HYDRALIC PUMP MOTOR FAULTY OR FAULTY HYDRALIC PUMP RELAY BEST TO LET MERCEDES BENZ DEALERSHIP CHECK IT OUT...

some cars with oil level warning light on, it doesn't mean that its only reading the engine oil level is low, sometime the transmission fuid too. Did you check your transmission fluid if it is ok or not? try to check and let us know, ok.

the ser soon light is a maint thing and can be reset if all maintance has be done the other symbol could be low coolant or low washer fluid check all your fluid levels frist.

Hello.
You can find the transmission level check dip stick under the hood near the back of the motor. Usually they can be found on the passenger side of the motor. Just look near the back of the motor, you will see a pull handle that says "Trans Fluid" just pull it out and check your fluid! Hope this helps!

the red break icon on if your brake fluid level is low also so check the level in your brake fluid bottle in the engine bay.if you have a yellow brake light on it means your brake pads are low get them checked.

reddish fluid can be
oil (dipstick on motor)
transmission fuild (dipstick on transmission)
brake fluid (transparent reservoir on vaccuum booster)
power steering fluid (transparent reservoir on PS pump)
maker's dye choice for the fluid filled,
Check fluid levels and top up any that are below recommended levels immediately, then monitor fluid levels and fix any that show evidence of leaks.
The check engine light is an indicator, it just says that 'something' in the list of functions it is monitoring is not right. a code reader can be plugged into a socket under the dash to reveal the most recent error codes.
Many repair shops (around here) will read the codes for you gratis, in the hope of getting the repair job.

sounds like a rear wheel cylinder