How electric parking brake works?
Traditionally, handbrakes or parking brakes consist of cables connected to the brake shoes or disk brakes, giving a decent amount of pressure to lock the wheels when pulled. The cabin side of the parking brake consists of a locking lever and a handle with a release button.
With the advent of technology, electronic handbrakes were invented. These parking brakes work on the same principle as their predecessor, but the handbrake lever is replaced by a push or pull button. Cables no longer exist and are replaced by wires. The mechanical actuator is replaced with electric motors with their own mechanical link to the calipers or brake shoes.
Should your car develop symptoms similar to the symptoms below, please feel free to read our step-by-step guide to guide you on how to diagnose a bad parking brake actuator.
Common symptoms of faulty parking brake actuator are:
- flashing parking brake light,
- message on the dashboard saying that a parking brake service is required.
What you will need
- Park the vehicle on safe and level ground.
- Place wheel chocks on the rear wheels.
- Use a tire wrench to loosen the affected wheel's lug nuts by turning the wrench counterclockwise.
- Using a jack, hoist the vehicle up and remove the wheel from the affected side using a tire wrench.
- Support the jack with a jack stand.
- Find the electrical connector to the caliper; once found, disconnect it for testing. Push the locking tabs and then pull the connector off.
- Check for power supply to the electric actuator motor. To accomplish this, you need to have a multi-meter tester. Set the multimeter to measure DC or direct current. Look for an icon with one straight line and three small horizontal lines parallel underneath the said straight line. Point the selector to the DC icon. Find the connector that leads to the body or main harness of the wiring. Place the black and red leads to both ends of the said connector.
8. Initially, there should be zero or a very low voltage reading. Have someone start the engine or turn the ignition on and set the parking brake on. If the voltage reading is in the range of 10-12 or -10 to -12 volts, then you have a decent power to the actuator. If there is no voltage or the voltage is lower than 10 volts, you should check the wiring or the fuse. Please note that the polarity, in this case, is irrelevant since you can interchange the leads.
- Note: Older multimeter testers have voltage ranges; you may set it to 20 volts or greater, do not set the voltage to any voltage settings that end with mv, MV means millivolts; using these settings on a 12-volt system could damage the multimeter.
9. Test actuator solenoid winding for continuity. The next step is to test the actuator winding for damage. You can carry out this task by finding the connector that is attached to the caliper.
- Check the multimeter set to continuity or ohms; the ohms icon is similar to the omega icon. You should do a multimeter self-test by connecting both leads and setting the beep on; the self-test should result in zero-ohm; if the result is greater than zero, there could be a problem with your test leads or multimeter.
- In this case, you should replace your multimeter or leads before doing the test.
- If self-test is ok, then connect both ends of the leads to both ends of the connector.
- If you hear a beep, then your actuator winding is good; and the problem could be coming from somewhere else, like the switch. But if the beep is not activated, then you have to replace your actuator solenoid.
10. Remove the jack stand.
11. Re-install the tire.
12. Fasten the lug nuts by turning the tire wrench clockwise.
13. Lower the jack and remove it.
14. Fasten the lug nuts.
15. To check the actuator on the other side, repeat steps 1-14.
Frequently Asked Questions
What could be the possible problem if parking brakes actuators are good at voltage is present on both caliper terminals?
- It could be as simple as a defective parking brake switch, or it could be the wiring, or it could be a damaged module.
Is the parking brake a separate braking system?
- Parking brakes can also be used if your main braking system fails. Thus it is also called an emergency brake. It is separate in actuation since it is engaged using electric actuators or mechanical actuators. Still, it uses the same braking components such as brake pads or brake shoes, calipers, or brake drums.