Test B: The Audio Unit Does Not Respond To The Diagnostic Tool

PINPOINT TEST B: THE AUDIO UNIT DOES NOT RESPOND TO THE DIAGNOSTIC TOOL

B1-B2:

B2-B3:

Normal Operation
The audio unit communicates with the diagnostic tool through the medium speed controller area network (CAN), circuits 1847 (WH/OG) and 1848 (PK/OG). Check circuits 1847 (WH/OG) and 1848 (PK/OG) between the audio unit C290a and the data link connector (DLC) C251.The total resistance values must not be more than 5 ohms. If the resistance is more than 5 ohms there is an open in one of the medium speed CAN circuits, damage to the DLC C251, damage to the audio unit connector, or damage to an in-line connector.

Possible Causes
- medium speed CAN circuit 1847 (WH/OG) open
- medium speed CAN circuit 1848 (PK/OG) open
- audio unit C290a
- audio unit