Workbook, Heavy Duty Truck Systems, 6E
Chapter Eleven – Answer Key
1. What can be said of current flow if a circuit is described as open?
2. What type of chassis data connector is required to access a SAE J1939 data bus?
3. When a DMM ammeter is used to measure current flow, which of the following should
be true?
4. Technician A says that a black J1939 chassis data bus connector may be used to connect
an EST to a MY2102 J1939 data bus. Technician B says that the reason for twisting the
pair of wires in chassis data bus wire pair is to help insulate the bus from low-level
radiation interference such as radio frequency (RF) waves. Who is correct?
5. What colors are used to identify the twisted wire pair used in a J1939 data bus?
6. Which GUI is found on most PCs in business use today?
7. What diagnostic software is required to work on a multiplexed Freightliner truck?
8. What is indicated when a CWS red light is illuminated?
d. Collision has occurred.
9. What identifies the cathode on a diode?
10. Take a look at the circuit schematic symbol for a standard SAE relay. What must happen
before current can pass through the 87 terminal? Discuss.