Air Antilock Brake Systems

Question 1

What are the two primary functions of the ABS system?

Answer 1

1. To help the operator maintain control throughout the braking application under less than ideal conditions.
2. To improve the chances of reducing overall stopping distance.

Question 2

The modulator valves send and recieve signals to and from the ECU.
True
False

Answer 2

False

Question 3

Which of the following is a four channel system? 
25/2M
4S/3M
6S/4M
6S/6M

Answer 3

6S/4M

Question 4

The order in which the ECU instructions the modulator valve to control air pressure is:

a. hold, reapply, exhaust
b. reapply, exhaust and hold.
c. exhaust, hold and reapply.
d. exhaust, reapply and hold.

Answer 4

c. exhaust, hold and reapply.

Question 5

On initial start up, the ABS warning lamp lights up and stays on to indicate to the operator that:

a. the system is active.
b. the system could be functioning property but must be driven above 5-10 mph to confirm.
c. there is an existing fault code.
d. either b or c.

Answer 5

d. either b or c

Question 6

During a normal braking situation, the antilock ECU:

a. only monitors wheel speeds
b. cycles the modulator valves
c. lights the indicator lamp
d. powers down to a sleep mode

Answer 6

a. only monitors wheel speeds

Question 7

During a braking situation, the ATC valve:

a. receives a signal from the ECU.
b. sends supply air out of the delivery port to apply the relay valve.
c. modulates application pressure.
d. allows brake application pressure to pass out the delivery port.

Answer 7

d. allows brake application pressure to pass out the delivery port.

Question 8

In order for the ATC system to reduce torque to the drive wheels, the engine must be electronically controlled.
True
False

Answer 8

True

Question 9

What are two primary functions of roll stability control?

Answer 9

a. Helps control vehicle stability.

b. Limit rollover conditions.

Question 10

What two truck systems work with RSC to help reduce reaction time when needed?

Answer 10

a. antilock brake system

b. electronic engine management

Question 11

What additional component is added to a vehicle equipped with ESC?

a. roll stability control valve.
b. ATC valve.
c. brake demand pressure switch.
d. steering angle sensor

Answer 11

d. steering angle sensor

Question 12

The tone ring is typically part of or attached to the:

a. spindle
b. drive shaft
c. brake drum
d. wheel hub.

Answer 12

d. wheel hub

Question 13

The wheel speed sensor sends a pulsed signal to the ECU.
True
False

Answer 13

True

Question 14

A tandem axle truck, tractor or bus has air ride suspensioin and a 4s/4m system. What axles would typically have wheel speed sensors?
a. front drive axle
b. rear drive axle
c neither drive axles
d. both drive axles

Answer 14

b. rear drive axle

Question 15

Where are the electronic control modules mounted on trucks, trailers and buses?

Answer 15

Inside the truck cab or bus baggage compartment, mounted to the frame or cross member or attached directly to the trailer air reservoir.

Question 16

Engine, exhaust and driveline retarders have sufficient braking capabilities to produce a wheel lockup condition and the abs system, to be effective, must be able to turn them off.
True
False

Answer 16

True

Question 17

As of March 1, 1998 the trailer antilock ECU receives power from:

a. an onboard power source
b. the auxiliary pin on the trailer cord.
c. the tail light pin of the trailer cord.
d. the largest pin of the trailer cord.

Answer 17

b. the auxiliary pin of the trailer cord.

Question 18

The ATC indicator warning lamp is used to:

a. indicate to the operator that the system is active.
b. indicate that the dyno-mode is activated.
c. indicate that the driver has activated the deep snow/mud switch.
d. all of the above.

Answer 18

d. all of the above.

Question 19

Vehicles equipped with ATC:
a. must not be tested on a chassis dynometer.
b. must have the atc system disabled before testing on a chassis.
c. typically produce 20% less torque and horsepower than rated.
d, typically produce 20% higher torque and horsepower than rated.

Answer 19

b. must have the ATC system disabled before testing on a chassis.

Question 20

What does the ecu monitor in order to respond to excessive speed on a curve?

Answer 20

The ECU measures the lateral or side to side movements of the vehicles.

Question 21

Explain the difference between roll stability control and electronic stabillity control.

Answer 21

Roll stability control doesn’t offer directional control of the vehicle.

Question 22

Which component allows for differential braking of the steer axleto help prevent spinout or jack knife conditions.

a. ATC valve
b. front axle control valve.
c. accelerometer
d. roll satiability control valve.

Answer 22

b. front axle control valve