Test H: The Smart Junction Box (SJB) Does Not Respond To The Scan Tool

PINPOINT TEST H: THE SMART JUNCTION BOX (SJB) DOES NOT RESPOND TO THE SCAN TOOL

H1:

H1-H3:

H3-H4:

Normal Operation
The SJB communicates with the scan tool through the medium speed controller area network (MS-CAN). Circuits VDB06 (GY/OG) (MS-CAN +) and VDB07 (VT/OG) (MS-CAN -) provide the network connection to the SJB. The SJB shares the MS-CAN network with the instrument cluster, the electronic manual temperature control module (if equipped), the electronic automatic temperature control (EATC) module (if equipped), the audio unit, the THX(R) amplifier (if equipped), the satellite radio receiver (if equipped), the driver seat module (DSM) (if equipped), the climate controlled seat module (if equipped), the power liftgate module (if equipped), the parking aid module (if equipped), the power running board module (if equipped), the auxiliary audio module (if equipped) and the digital versatile disc (DVD) player (if equipped). Voltage for the SJB is provided by circuit CDC33 (VT/GN). Circuit GD133 (BK) provides ground.

DTC U0140 - sets in a module which had attempted to communicate with the SJB and failed.

Possible Causes
- Fuse
- Circuit CDC33 (VT/GN) open
- Circuit GD133 (BK) open
- Circuit VDB06 (GY/OG) open (MS-CAN +)
- Circuit VDB07 (VT/OG) open (MS-CAN -)
- SJB