There are 2 main types of warning lights for the brake system. One lets you know that the parking brake is engaged, symbolized with a “P” and the other to warn you that there is an issue with the system, symbolized with a “!”. Many car manufacturers combine these into one light to simplify things a little bit. Usually there will be the word “brake” written out as well.
What the brake warning light means
As mentioned before, the brake light may be on because the parking brake is engaged. If disengaging the parking brake doesn’t turn off the light, then the computer has detected an issue with the braking system. Most commonly, this may be due to an issue with the brake fluid.
The brake fluid reservoir has a fluid level sensor built in to make sure there is sufficient fluid in the system at all times. As your brake pads wear out, more fluid is pushed into the lines which lowers the overall level in the system. If the pads get too thin, the fluid level will go down too much and trip the sensor. A leak in the system will also cause the sensor to trip and the light will illuminate to warn you of the low levels.
What to do when the brake warning light is on
If the light is on, first check to make sure that the parking brake is fully disengaged and then check the fluid level inside the reservoir. If neither of these seem to have any issue, then you should have your parking brake cable inspected and adjusted, if necessary. A cable that is out of adjustment may not completely disengage the parking brakes even if the handle is released. If the vehicle is low on fluid, have the pads and brake lines inspected for leaks or worn out parts.
Is it safe to drive with the brake warning light on?
Depending on how severe the issue is, the car may or may not be safe to drive. If the light comes on, you should pull over safely out of traffic to check the parking brake and fluid level. With a severe fluid leak, you will not be able to use the brake pedal to stop the car quickly and you will have to use the parking brake to slow the vehicle down. This is risky as the parking brake is not nearly as effective at stopping the vehicle as the brake pedal.
If your parking brake isn’t fully disengaging, it is recommended that you get your car towed as the constant resistance is not good for your vehicle’s drivetrain.
If your brake warning light is on and you can’t find the reason, one of our certified technicians would be able to assist you in diagnosing the issue.
This article originally appeared on YourMechanic.com as What Does the Brake System (Hand Brake, Parking Brake) Warning Light Mean? and was authored by Spencer Cates.