ABS basics
What does ABS stand for?
Anti-lock Brake System
Name the sensor that detects wheel speed.
Wheel speed sensor
What does TCS stand for?
Traction Control System
TCS uses the same sensors as what system?
ABS system
What warning light illuminates when ABS has a fault?
ABS warning light
True or False – ABS allows the wheels to lock up during hard braking.
False - ABS reduces the amount of wheel lock up during hard braking
What component controls the hydraulic pressure in an ABS system?
ABS module/electro-hydraulic unit
What driving situation does TCS mainly help prevent?
Wheel spin during acceleration
Name one way TCS can reduce engine torque.
Cutting fuel, retarding spark timing, or closing throttle
What’s the first step when diagnosing an ABS/TCS fault?
Scan for fault codes
Visual inspection of the vehicle
ABS works by rapidly doing what to brake pressure?
Modulates brake pressure
What part of the system decides when to activate ABS?
ABS control unit
Which system is traction control often integrated with?
ABS system
The sensor responsible for measuring forward/rearward acceleration is called what?
G-force sensor
When confirming what type of sensor we are dealing with, what is the main determining factor?
Check for a bias voltage
What is the main benefit of ABS during emergency braking?
Maintain control while braking
True or False – ABS uses separate brake pads from the normal system.
False - the ABS system uses the same brake pads as the regular brake system
True or False – TCS reduces engine power and/or applies brakes to regain traction.
True - the TCS can reduce engine power and apply brakes to reduce wheel spin
The front right wheel
What type of signal can be expected on a oscilloscope on a vehicle equipped with inductive wheel speed sensors?
Analog/AC
In what driving condition is ABS most effective: dry pavement, gravel, or snow? Explain why.
Dry pavement – provides the best friction and stopping distance
What are the 2 type of wheel speed sensors?
Passive (inductive) and Active (hall effect)
What’s the difference between ABS and TCS in terms of wheel motion control?
ABS controls wheel negative wheel slip (lock up)
TCS controls positive wheel slip (spinning wheels)
What control unit, is responsible for processing the TCS's request to lower engine output?
Engine control unit
What is an important step in diagnosing if there is a wiring issue with the wheel speed sensor?
harness resistance check