semplr.

Exams · Certifications · Licensing

Red Seal Automotive Service Technician Exam (Interprovincial)

C. Vehicle module communications: practice questions

Our Red Seal Automotive Service Technician bank has 22 questions on this topic. Here are 5 of them with answers; the full mock exam draws from every topic, like the real one.

Start the free mock exam

Question 1

A module shorting the CAN bus can take the whole network down. A common way to find it is:

  1. Replace the PCM first, because it is the gateway to all other modules
  2. Clear codes repeatedly
  3. Disconnect the battery for an hour
  4. Disconnect modules one at a time and watch whether the bus recovers
Show the answer

D. Disconnect modules one at a time and watch whether the bus recovers — Isolating modules one at a time locates the one loading or shorting the bus.

Question 2

Standard CAN uses an 11-bit identifier. Extended CAN uses:

  1. A 16-bit identifier
  2. A 29-bit identifier
  3. An 8-bit identifier
  4. A 64-bit identifier
Show the answer

B. A 29-bit identifier — The standard was amended with the extended 29-bit identifier.

Question 3

LIN bus is typically used for:

  1. High-speed airbag deployment signals that must reach the airbag module within a millisecond
  2. Engine timing signals
  3. Low-speed, single-wire links to simple devices such as switches and mirrors
  4. High-voltage battery power
Show the answer

C. Low-speed, single-wire links to simple devices such as switches and mirrors — LIN is a low-cost, low-speed sub-network under a master module.

Question 4

Which network protocols does the RSOS list for vehicle module communication?

  1. USB, HDMI and SATA
  2. ISO, CAN, LIN and wireless
  3. Ethernet only
  4. RS-232 and parallel
Show the answer

B. ISO, CAN, LIN and wireless — Network protocols include ISO, controller area network (CAN), local interface network (LIN) and wireless.

Question 5

With the battery disconnected, you measure resistance between CAN High and CAN Low at the DLC. What is the normal reading?

  1. About 120 Ω
  2. About 240 Ω
  3. 0 Ω
  4. About 60 Ω
Show the answer

D. About 60 Ω — Two 120 Ω terminating resistors in parallel measure about 60 Ω; 120 Ω suggests one terminator or a break.

More Red Seal Automotive Service Technician topics