Test O: No Medium Speed Controller Area Network (CAN) Communication

PINPOINT TEST O: NO MEDIUM SPEED CONTROLLER AREA NETWORK (CAN) COMMUNICATION

O1-O3:

O3-O5:

O5-O8:

O8-O11:

O12-O15:

O16-O19:

O20-O23:

O24-O26:

O27-O28:

O29-O30:

O30-O32:

O33-O37:

O38-O40:

Normal Operation
The following modules communicate using the medium speed CAN:
- instrument cluster
- smart junction box (SJB)
- driver door module (DDM) (if equipped)
- driver seat module (DSM) (if equipped)
- heated seat module (if equipped)
- climate control assembly
- audio control unit
- THXII audio unit (if equipped)
- digital signal processing module (if equipped)

The following modules communicate using the medium speed CAN:

The medium speed CAN has an unshielded twisted pair cable, circuits VDB06 (GY/OG) and VDB07 (VT/OG).

For normal operation of the medium speed CAN, correct network termination resistance is required. The SJB and the instrument cluster share communications network termination responsibilities with the use of a split termination resistor in each module.

Check the medium speed CAN circuits between each network module 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 one of the module connectors, or a problem in an in-line connector.

The vehicle can be equipped with either a electronic automatic temperature control (EATC) module or a dual automatic temperature control (DATC) module, referred to as the climate control assembly.

Possible Causes
- medium speed CAN data plus circuit VDB06 (GY/OG) open
- medium speed CAN data minus circuit VDB07 (VT/OG) open
- DLC C251
- instrument cluster C220
- SJB C2280d
- DDM C568a (if equipped)
- DSM C3299c (if equipped)
- climate controlled seat module C3305c (if equipped)
- climate control assembly EATC module C228a or DATC module C2356a
- audio unit C290b
- THXII audio unit C240c (if equipped)
- digital signal processing module C4326a (if equipped)
- instrument cluster
- SJB
- DDM (if equipped)
- DSM (if equipped)
- climate controlled seat module (if equipped)
- climate control assembly
- audio unit
- THXII audio unit (if equipped)
- digital signal processing module (if equipped)