CAN BUS Training

Question 1

Before performing any BUS diagnosis, you must first do what?

Answer 1

Check the battery voltage. A weak/dead/low battery an cause issues

Question 2

True or false: you can check for an internal short between the BUS wires in a module by checking that their resistance is 60 Ohms?

Answer 2

False… why?? Explain

Question 3

If you disconnect the BUS at a connector or module and there is still a low resistance between pins 6 and 14 on the DLC, then…

Answer 3

… the fault must be between the DLC and the disconnection.

Question 4

How do you check to see if the high speed BUS is asleep?

Answer 4

Measure the Voltage between pins 6 and 14 on the DLC

Question 5

How can you determine which modules are communicating on the high speed BUS?

Answer 5

Use a scan tool and run a network test!

Question 6

A possible cause of a high speed BUS fault could be…

Answer 6

… short to ground, a short between the BUS wires, or an open ckt