Test J: The Electronic Automatic Temperature Control (EATC) Module Does Not Respond To The Scan Tool

PINPOINT TEST J: THE ELECTRONIC AUTOMATIC TEMPERATURE CONTROL (EATC) MODULE DOES NOT RESPOND TO THE SCAN TOOL

J1-J2:

J3-J4:

Normal Operation
The EATC module 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 EATC module. The EATC module shares the MS-CAN network with the instrument cluster, the smart junction box (SJB), the audio unit, the THX(R) amplifier (if equipped), the satellite radio receiver (if equipped), the auxiliary audio module, the digital versatile disc (DVD) player, the driver seat module (DSM) (if equipped), the power running board module, the parking aid module (if equipped), the power liftgate module and the climate controlled seat module (if equipped). Voltage for the EATC module is provided by circuits CBP37 (WH) and SBP15 (WH/RD). Circuit GD133 (BK) provides ground.

DTC U0164 - sets in a module which had attempted to communicate with the EATC module and failed.

Possible Causes
- Fuse
- Circuit CBP37 (WH) open
- Circuit GD133 (BK) open
- Circuit SBP15 (WH/RD) open
- Circuit VDB06 (GY/OG) open (MS-CAN +)
- Circuit VDB07 (VT/OG) open (MS-CAN -)
- EATC module