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

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

B1-B2:

B3-B5:

Normal Operation
The EATC module communicates with the scan tool through the medium speed controller area network (MS-CAN), circuits 1827 (WH/LG) and 1828 (PK/LG). The EATC shares the MS-CAN with the instrument cluster and the smart junction box (SJB). Power for the EATC is provided by redundant circuits. Circuits 298 (VT/OG) and 385 (WH/RD) provide voltage, and circuit 651 (BK/YE) provides ground.

Possible Causes
- Fuse
- Circuit 298 (VT/OG) open
- Circuit 385 (WH/RD) open
- Circuit 651 (BK/YE) open
- Circuit 1827 (WH/LG) open (MS-CAN +)
- Circuit 1828 (PK/LG) open (MS-CAN -)
- EATC module