Toyota corolla brake light on dashboard

I have Toyota corolla 2000 VE with 144K miles. Last month, I noticed the brake light on my dashboard come up even when handbrake was off. I went to my mechanic and he added more brake oil to the car which made brake light go away. Now today, the brake light has come back up again. It stays on sporadically, sometimes for 20 secs or less. I don’t think brake oil is the problem anymore. brake oil won’t get consumed so fast ( fall below threshold) Could it be brake pads?
I’ll take my car to mechanic tomorrow but just wanted to know what could be possible cause of this.
Thank you

Have you checked the brake fluid (not oil) level since the light came on again?
Get someone at the shop to show you how, if necessary.
If it’s low again you have a leak.
This is something to get fixed right away.

What led you to believe the oil won’t disappear that fast? @circuitsmith is right - sounds like you have a leak.

@Hughes - I agree, sounds like a leak, you need to get it fixed. And like @circuitsmith said, it’s brake fluid, not oil. Recently somebody posted about putting oil in the brake fluid reservoir, could cause major ($$$) damage.

Pardon my ignorance, what’s the difference between brake fluid and brake oil? If there is a leak, will I be able to tell by looking under the car?

No such thing as brake oil for cars.
Look for stains on the brakes & rims.

Never heard Brake fluid being called Brake oil.

ok, thanks! I didnt know that.
I will check for ‘brake fluid’ and take the car to mechanic.
thanks folks

I’ve seen some people call brake fluid “brake oil.” I always chalked it up to regional oddities like calling a drinking fountain a “bubbler” in eastern Wisconsin.

Anyway, no difference. Brake fluid is an oil.

No, brake fluid is not an ‘oil’, which to me is a hydrocarbon. It’d be like calling antifreeze ‘oil’. Brake fluid is a glycol ether, water soluble, unlike any oil

Quite true. It used to be oil, but isn’t any longer. Thanks for the correction.

Well, now I’m really puzzled. Brake fluid’s always been a glycol, as far as I remember ('60s). Not trying to be argumentative, mind you.

DOT-5 is an oil (silicone oil), but I bet that’s not what you’re talking about.

Yeah, this is a little before your (and my) time. Brake fluid in really old cars that had natural rubber lines was often a castor oil/alcohol mix, because the castor oil was the only oil that wouldn’t damage the rubber.

Here’s a link to a patent filed in 1939 that discusses the invention that was one of the leaders in sunsetting castor oil as brake fluid.

Learn something new every day…

If it is not low brake fluid, a brake light out will light the brake light.

If there’s a rear light out on a Toyota, it will cause the individual rear light out warning light to come on. Not the main brake warning light.

If you find that brake fluid level has dropped again, there could be a leak at the rear seal of the brake master cylinder. This can be hard to detect unless the master cylinder is removed from the brake vacuum booster.


OP should do a visual check of the brake fluid. Look in the owners manual to get instructions. If it is at or below the “low” mark, that could turn on the dashboard brake light. In any event, if the brake fluid level is low, whatever is causing it, that needs immediate att’n as it is a safety issue.

Another idea, unlikely, but it could be the alternator that is the actual problem.

If the fluid is at the correct level and the light is on the float may be stuck. Tap the reservoir and see if the lamp goes off. It is not un common for the float and sensor to fail. If you are loosing fluid you have a leak.


Soda, tonic, pop, coke, what difference does it make?

Technically, we might argue the attributes of an oil vs. the attributes of a “fluid” created to accomplish a different task, such as a hydraulic fluid, and we might even argue the attributes of silicon oil vs. coconut oil, but the important thing is that the OP get his/her brake system checked out. I commend the OP for following through on this.

For the record, I hope the guy who topped off the fluid did at least a cursory look at the pads and for evidence of a leak. If he/she did not find significant pad wear, and found no leak tracks, I hope he/she at least checked the float and checked to see that the parking brake adjustments were not the source of the light.

For the record castor oil is extracted from castor beans and is a vegetable oil not a petroleum oil. The reason OP did not know the difference between brake fluid and oil is that they never had a need to. We all need to remember that many posters are asking for help because they have no clue. Others like myself are limited in knowledge and experience concerning modern vehicles. In this case the OP learned one minor lesson in automotive terminology and acknowledged it. The important thing is that they get their brakes (very important safety system) properly diagnosed and repaired.