402d Air ABS Flashcards
What are the two (2) primary functions of an ABS system?
- to help the operator maintain control throughout the braking application under less than ideal conditions
- to improve the chances of reducing overall stopping distances
The tone ring is typically part of or attached to the:
wheel hub.
The modulator valves send and receive signals to and from the ECU.
T/F
false; the modulator does not send signals to the ECU
The wheel speed sensor sends a pulsed signal to the ECU.
T/F
true
Which of the following is a four-channel system?
a) 2S/2M
b) 4S/3M
c) 6S/4M
d) 6S/6M
6S/4M
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?
rear drive axle
The order in which the ECU instructs the modulator valve to control air pressure is:
exhaust, hold and reapply.
Where are electronic control modules mounted on truck/tractors, buses and trailers?
inside the truck cab or bus baggage compartment, mounted to the frame or cross member or attached directly to the trailer air reservoir.
On initial start-up, the ABS warning lamp lights up and stays on to indicate to the operator that:
- the system could be functioning properly, but must be driven above 5 to 10 km/h to confirm.
- there is an existing fault code.
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
true
During a normal braking situation, the antilock ECU:
only monitors wheel speeds.
As of March 1, 1998, the trailer antilock ECU receives its power from:
the auxiliary pin of the trailer cord.
During a braking situation, the ATC valve:
allows brake application pressure to pass out the delivery port.
The ATC indicator/warning lamp is used to:
3
- 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.
In order for the ATC system to reduce torque to the drive wheels, the engine must be electronically controlled.
T/F
true
Vehicles equipped with ATC typically produce 20% less torque and horsepower than rated.
T/F
False, they must have the ATC system disabled before testing on a chassis dynamometer.
What are the two (2) primary functions of roll stability control?
- help control vehicle stability
- limit rollover conditions
What does the ECU monitor in order to respond to excessive speed on a curve?
The ECU measures the lateral or side-to-side movements of the vehicle.
What two (2) truck systems work with RSC to help reduce reaction time when needed?
- antilock brake system
- electronic engine management
Explain the difference between roll stability control and electronic stability control.
Roll stability control does not offer direction control of the vehicle.
What additional component is added to a vehicle equipped with ESC?
steering angle sensor
Which component allows for differential braking of the steer axle to help prevent spinout or jackknife conditions?
front axle control valve
