ADT Network Communication & CAN Bus Systems

Question 1

What is the standard data transmission speed of the high-speed powertrain CAN bus used in Audi vehicles?

Accepted Answer

500 kbps

Answer

High-speed CAN (HS-CAN) used for powertrain communication in Audi vehicles typically operates at 500 kbps.

Question 2

Which two conductors form the twisted pair in an Audi CAN bus network?

Accepted Answer

CAN High and CAN Low

Answer

A CAN bus uses a differential pair consisting of CAN High (CANH) and CAN Low (CANL) twisted together to cancel electromagnetic interference.

Question 3

What is the standard termination resistance value placed at each physical end of a CAN bus network?

Accepted Answer

120 ohms

Answer

Each end of a CAN bus is terminated with a 120-ohm resistor to prevent signal reflections on the network.

Question 4

With all modules disconnected, a technician measures resistance across CAN High and CAN Low. What reading confirms both termination resistors are present and correct?

Accepted Answer

60 ohms

Answer

Two 120-ohm termination resistors wired in parallel produce a combined resistance of 60 ohms across the CAN pair.

Question 5

What is the CAN High wire voltage during a dominant bit in a standard Audi high-speed CAN bus?

Accepted Answer

3.5V

Answer

During a dominant bit, CAN High rises to approximately 3.5V while CAN Low drops to approximately 1.5V, creating the differential signal.

(ADT) Audi Diagnostic Technician Practice Test

(ADT) Audi Diagnostic Technician Practice Test

ADT Network Communication & CAN Bus Systems