402d Air ABS

Question 1

What are the two (2) primary functions of an ABS system?

Answer 1

• to help the operator maintain control throughout the braking application under less than ideal conditions
• to improve the chances of reducing overall stopping distances

Question 2

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

Answer 2

wheel hub.

Question 3

The modulator valves send and receive signals to and from the ECU.
T/F

Answer 3

false; the modulator does not send signals to the ECU

Question 4

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

T/F

Answer 4

true

Question 5

Which of the following is a four-channel system?

a) 2S/2M
b) 4S/3M
c) 6S/4M
d) 6S/6M

Answer 5

6S/4M

Question 6

A tandem axle truck, tractor or bus has air ride suspension and a 4S/4M system. Which drive axle(s) would typically have wheel speed sensors?

Answer 6

rear drive axle

Question 7

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

Answer 7

exhaust, hold and reapply.

Question 8

Where are electronic control modules mounted on truck/tractors, buses and trailers?

Answer 8

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

Question 9

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

Answer 9

• the system could be functioning properly, but must be driven above 5 to 10 km/h to confirm.
• there is an existing fault code.

Question 10

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.
T/F

Answer 10

true

Question 11

During a normal braking situation, the antilock ECU:

Answer 11

only monitors wheel speeds.

Question 12

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

Answer 12

the auxiliary pin of the trailer cord.

Question 13

During a braking situation, the ATC valve:

Answer 13

allows brake application pressure to pass out the delivery port.

Question 14

The ATC indicator/warning lamp is used to:

3

Answer 14

• indicate to the operator that the system is active.
• indicate that dyno-mode is activated.
• indicate that the driver has activated the deep snow/mud switch.

Question 15

In order for the ATC system to reduce torque to the drive wheels, the engine must be electronically controlled.
T/F

Answer 15

true

Question 16

Vehicles equipped with ATC typically produce 20% less torque and horsepower than rated.
T/F

Answer 16

False, they must have the ATC system disabled before testing on a chassis dynamometer.

Question 17

What are the two (2) primary functions of roll stability control?

Answer 17

• help control vehicle stability

- limit rollover conditions

Question 18

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

Answer 18

The ECU measures the lateral or side-to-side movements of the vehicle.

Question 19

What two (2) truck systems work with RSC to help reduce reaction time when needed?

Answer 19

• antilock brake system

- electronic engine management

Question 20

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

Answer 20

Roll stability control does not offer direction control of the vehicle.

Question 21

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

Answer 21

steering angle sensor

Question 22

Which component allows for differential braking of the steer axle to help prevent spinout or jackknife conditions?

Answer 22

front axle control valve