ADT Network Communication & CAN Bus Systems 1 — Questions and Answers
Question 1: What is the standard data transmission speed of the high-speed powertrain CAN bus used in Audi vehicles?
- 33.3 kbps
- 125 kbps
- 500 kbps (Correct answer)
- 1 Mbps
Correct answer: 500 kbps
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?
- CAN High and chassis ground
- CAN High and CAN Low (Correct answer)
- CAN Low and 12V supply
- Signal wire and shield wire
Correct answer: CAN High and CAN Low
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?
- 60 ohms
- 100 ohms
- 120 ohms (Correct answer)
- 150 ohms
Correct answer: 120 ohms
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?
- 240 ohms
- 120 ohms
- 60 ohms (Correct answer)
- 0 ohms
Correct answer: 60 ohms
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?
- 0V
- 1.5V
- 2.5V
- 3.5V (Correct answer)
Correct answer: 3.5V
During a dominant bit, CAN High rises to approximately 3.5V while CAN Low drops to approximately 1.5V, creating the differential signal.
Question 6: Which Audi/Volkswagen Group factory diagnostic software is the current standard for CAN network diagnosis, guided fault finding, and ECU flash programming?
- VCDS (VAG-COM)
- ODIS (Offboard Diagnostic Information System) (Correct answer)
- ISTA+
- GlobalTIS
Correct answer: ODIS (Offboard Diagnostic Information System)
ODIS (Offboard Diagnostic Information System) is the official Volkswagen Group factory-level tool used by Audi dealers for comprehensive vehicle diagnosis and programming.
Question 7: Which CAN network variant in Audi vehicles typically operates at 100 kbps and is used for comfort and body electronic modules?
- High-speed CAN (HS-CAN)
- Low-speed fault-tolerant CAN (LS-CAN) (Correct answer)
- FlexRay
- MOST bus
Correct answer: Low-speed fault-tolerant CAN (LS-CAN)
Low-speed fault-tolerant CAN operates at 100 kbps and is used for body/comfort systems; it can continue single-wire operation if one conductor is damaged.
ADT Network Communication & CAN Bus Systems 1
What is the standard data transmission speed of the high-speed powertrain CAN bus used in Audi vehicles?