ATASA 5 TH Study Guide Chapter 51 Pages: 1506 1534 Antilock Brake Systems 59 Points Please Read The Summary
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1. ABS systems use an / pumping of the brakes to control straight line stopping under panic conditions. (ABS is very fast, up top 15 x/second, & very precise) Electronic/Hydraulic Mechanical/Chemical Electrical/Solar
2. Pressure is the term used to describe the quick apply & release of brake system pressure by the antilock brake system. (preventing lock up leads to better maneuverability & stability) Modulation Cavitation Electrification
3. is the difference between the actual speed of the vehicle and the speed of the tire s tread as it rotates on the pavement. With ABS, the target slip rate is 10% to 30% Slip Rate Clip Rate Ship Shape
4. It s the traction of the that actually stops the vehicle. ABS adjusts slip rate at each tire. Wheels Tires Pads & Shoes
5. If the driver pumps the brakes while stopping, this prevents ABS from activating! True or False
6. When ABS is activated, a small followed by rapid pedal will continue until the vehicle either comes to a stop or the ABS turns off. Grind, Vibration Bump, Pulsations Thump, Reverberation
7. There are both and / components in each ABS system. These are also used for traction control system operation. Hydraulic, Electrical/Electronic Pneumatic, Electrical/Electronic Polytechnic, Electrical/Electronic
8. The nitrogen charged is used to store the hydraulic fluid used to maintain high ABS pressure. It may also be used to store residual pressure for power assisted braking. Accumulator Defibrillator Modulator
9. The control valve assembly may be an part of the master cylinder assembly or may be mounted externally away from the master cylinder (non integral). Extrinsic Integral Add on
10. The pump, an assembly of an electric motor & pump, provides pressurized fluid. Booster Rooster Master Cylinder
11. The booster/ master cylinder assembly, sometimes referred to as the hydraulic unit, contains the valves and pistons needed to modulate hydraulic pressure. Control Retro Master
12. Fluid are different than pressure accumulators. They are used to temporarily store brake fluid removed from the wheel brake units during an ABS cycle. Accumulators Retractors Integrators
13.The valve is a two position valve that is only open during the ABS mode. Main Solenoid Actuator
14. The unit is made up of solenoid valves used to either, increase, decrease, or maintain hydraulic pressure to the individual wheel units. The valve block may also contain solenoids. Accumulator Defibrillator Modulator
15. There are two solenoid valves known as wheel valves used to control each channel. Circuit Circus Sirius
16. The ABS control module relies on input from the speed sensors and feedback from the hydraulic unit to determine if ABS is operating properly or which mode of ABS is required. Crankshaft Transmission Wheel
ABS is part of the High Speed CAN. There are also Medium Speed and Low Speed Controller Area Networks on the vehicle.
17. The brake position sensor (BPP) determines pedal travel & signals the ECU that an ABS event is taking place. This along with wheel speed sensor input causes a system reaction. Bracket Pedal Light
18. ABS systems have their own for faults which are accessed through the OBDII DLC. DTCs PIDs KIDs
19. The colored warning lamp illuminates during vehicle startup & ABS system self check as well as when a DTC (Diagnostic Trouble Code) is stored. Red Amber Blue
20. A acceleration sensor is used on vehicles with ABS and stability control. Radial Lateral Circular
21. A switch automatically controls the ground side of the pump relay energizing and de energizing the pump to maintain proper accumulator pressure. Pressure Solenoid Actuator
22. The ABS system has that complete the high current circuits for the pump motor. Relays Solenoids Breakers
23. The ring (reluctor or toner ring) of the wheel speed sensing device can be located on an axle shaft, differential gear, or a wheel hub. Gear Toothed Fanged
24. The wheel speed sensor (coil & permanent magnet) & toner ring generate an voltage signal. AC DC MC
25. The electronic circuit & wiring of ABS is tied into the vehicle s CAN. This is a means of transferring information between computers on a serial data bus. (Multiplexing) Network Channel Circuit
26. The ABS control unit operates / valves in the hydraulic control unit that block off or isolate the master cylinder from certain brakes. These are corner specific valves. Isolation/Dump Insulation/Bump Isolation/Pump
27. Manufacturers have unique ways of accomplishing ABS operation. systems with conventional power assisted master cylinders & separate ABS hydraulic control units are typical. Integral Non integral
28. is the name given to a hydraulic circuit to the brakes. (ABS can be 1,2,3, or 4 channel) Channel Canal Actuator
29. Light trucks and some SUV s use 1 channel ABS on just the brakes. (RWAL or RABS) Rear Wheel Anti Lock Rear Antilock Brake System Rear Right Left
30. A diagonally split system may us a channel system that modulates opposite corners. 2 3 4
31. A channel system will individually control each front brake but employ an RWAL system. 2 3 4
32. The most effective and most commonly available ABS is the channel system with a sensor for each wheel. Normal braking is done by a conventional vacuum power assist system. 2 3 4
33. Based on input from wheel speed sensors, the ABS control module calculates the rate of the wheels and then controls the brake fluid pressure to reach the target slip rate. Slant Slip Tractive
34. sensors are variable reluctance sensors or permanent magnet generators. Air Speed Wheel Speed Bad Seed
35. As wheel speed changes, sensor AC and change in accordance. Frequency & Amplitude Attitude & Freakiness Altitude & Frequency
36. Hydraulic control in the ABS modulator assembly has 3 modes of operation: 1) Pressure REDUCTION, 2) Pressure RETAINING, 3) Pressure INTENISFYING. (dump, hold, build)
The ABS system is self monitoring. Every time the ignition switch is placed in the ON/RUN position, the control module will perform a preliminary self check. The amber ABS light is illuminated during this test and will shut off if no problems are detected and no DTC s are stored. (Lamp Fault Codes)
A system malfunction will cause the control module to shut off or inhibit the ABS system however, normal power assisted braking remains.
37. Automatic control (ATC) systems apply the brakes when a drive wheel attempts to spin and lose traction. The goal is still controlling wheel slip rate. Treason Traction Technical
38. controls negative wheel slip and controls positive wheel spin. ABS, ATC
39. The EBCM and the PCM will work together to reduce engine during traction control mode. This can be accomplished through retarding spark timing, closing the throttle, limiting injector pulse width, increasing EGR flow, and up shifting the transmission. Torque Compression Horsepower
40. When ATC is actively controlling wheel spin, a lamp is illuminated on the cluster. *Green? Red Blue
41. Some traction control systems have a manual switch. The amber colored traction control system lamp on the instrument cluster will then be illuminated. Cut off Back off Slack off
42. Electronic control (ESC) helps prevent skids, swerves, and rollovers. Torque Stability Horsepower
43. is a condition where the vehicle is slow to respond to steering changes. (plow)
44. is a condition when the rear wheels try to swing around or fishtail. (loose)
45. is defined as the natural tendency of a vehicle to rotate on its vertical axis.
46. is the tendency of a vehicle to rotate on its horizontal axis. Pitch Roll Yaw
47. A vibration type senses understeer & oversteer signaling the need to correct yaw. Vibratory Gyroscope an instrument for determining the angular velocity of an object; contains vibrating parts that react to the object s rotation. There are bar and rotor types of vibratory gyroscope. The sensing element in the bar type is formed by several vibrating objects similar to the bars of a tuning fork. Gyroscope
48. ABS, ATC, and ECS Safety Precautions are listed on page. 1523 1524
49. An important thing to remember about ABS service is to relieve pressure BEFORE performing any hydraulic system service. 28,000 psi of pressure may be present! Accumulator Decumulator Evaporator
50. A common method of depressurization is to the pedal 25 times with the ignition key off. Pump Stump Clump
51. All ABS systems have some sort of,activated each time the ignition switch is turned on (KOEO). Self Test Written Test Blood Test
52. A solid (not flashing) ABS lamp indicates a has been detected and ABS is inhibited although normal power assisted braking is still present. A flashing lamp means repair ASAP! Problem Situation Fault
53. ABS fault codes cannot be until all faults have been corrected and the vehicle has been driven for a manufacturerspecified rate and distance. Erased Repaired Cleared
54. Many of the components in an ABS system are serviced by only. Rebuilding Reflashing Replacement
55. Brake is one area of service that will vary by manufacturer and system design. Bleeding Adjusting Replacing
56. The auto brake system continues to evolve with things like calipers, brake by wire, electronic wedge brakes, rain sensing brakes that apply to self dry and hill hold features. Electric Hydraulic Pneumatic
In a drive by wire throttle control system, inlet air, fuel injection and ignition timing are also backed off during drive wheel slippage when ATC is energized. (manual cut off of ATC is available) Throttle Actuator Motor
It s wise to disconnect vehicle computers before arc welding on any vehicles.
Scanners may also energize systems for bleeding.