Test F: No Medium Speed Controller Area Network (MS-CAN) Communication, All Modules Are Not Responding

PINPOINT TEST F: NO MEDIUM SPEED CONTROLLER AREA NETWORK (MS-CAN) COMMUNICATION, ALL MODULES ARE NOT RESPONDING

F1-F2:

F3-F4:

F5-F7:

F7-F8:

F9-F11:

F11-F13:

F13-F16:

Normal Operation
The MS-CAN uses an unshielded twisted pair cable, circuits 1827 (WH/LG) and 1828 (PK/LG). The smart junction box (SJB), instrument cluster and electronic automatic temperature control (EATC) module all communicate with the scan tool using the MS-CAN.

DTC U0020 (Instrument Cluster) - sets when the MS-CAN bus performance is compromised.

DTC U0073 (EATC ) - sets when there is a communication problem on the CAN bus.

DTC U1900 (SJB) - sets when there is a general CAN bus failure and the SJB is not receiving CAN messages.

Possible Causes
- Circuit 1827 (WH/LG) open, short to ground or voltage (MS-CAN +)
- Circuit 1828 (PK/LG) open, short to ground or voltage (MS-CAN -)
- Circuit 1827 (WH/LG) (MS-CAN +) and circuit 1828 (PK/LG) (MS-CAN -) shorted together
- SJB
- EATC module
- Instrument cluster