I need help fast!

My 99 4runner (F) lighton the instr. cluster came on in the vehicle while my wife was driving home from work.We're trading it in this friday morning. I've never had a lick of problem with the truck. Owners manual says A. low gas level. B. loose cap. or C. eng. malfuction/ eletric problem, see local dealer.

So the fuel was down to about empty, so the wife put 5 gal. in and drove home 5to 7 miles. The light on the cluster stayed on. Vehicle runs fine, cap is tight, And I'm out of state trying to figure out how to fix or reset the vehicle. If anyone can help we would be thankful. I just hate to drive it to the dealership with a light on/ problem.
Thanks
Ron

Try pulling the ECU fuse, it is located in the engine compartment fuse box. Leave it out for at least 10 seconds. The code will temporarily be cleared but will return if fault is not remedied.
Try another cap I have heard of these causing this problem but not on 4Runners though.

Don't waste your money buying parts if you don't know what code is stored in your computer. If you want to fix it, get the code and tell us what it is.

Thanks for the Help guy, I went to the local auto parts store and they ran the code. It came up 0170 which I was told eng. running lean, which also means the o2 senor if I'm correct. He stated I will get poor mileage, or something else. He then cleared the code. I asked how much it would be if i replaced part. He stated from 65.00 to 175.00 to 365.00.
Had him clear it.
Thanks again

If it's really o2 sensor, part itself if you buy it from dealer will be from 150$ to 175$ , at the store you will get it for 128$. I wanted original ,so i bought it from dealer and replaced it myself it's pretty simple.

The lean fuel/air ratio errors are usually a "two trip" code.
It takes two consecutive errorson two consecutive "trips" before it will log the code and enable the light.

What i did , i went to shop and they checked code on computer, then they told me what needs to be replaced. It costs money ,but atleast I didn't have to pay for repair.

What did you need to replace?

I replaced 0xygen sensor.