Test D: The Electronic Automatic Temperature Control (EATC) Module Does Not Respond to the Scan Tool

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

D1-D3:

D3-D4:

Normal Operation
The EATC module communicates with the scan tool through the UBP communication network. Circuit 1906 (VT) provides the network connection to the EATC module. The EATC module shares the UBP network with the instrument cluster, the vehicle security module (VSM) (if equipped) and the driver seat module (DSM) (if equipped). Voltage for the EATC module is provided by circuits 296 (WH/VT) and 729 (RD/WH). Circuit 875 (BK/LB) provides ground.

Possible Causes
- Fuse
- Circuit 296 (WH/VT) open
- Circuit 729 (RD/WH) open
- Circuit 875 (BK/LB) open
- Circuit 1906 (VT) open
- EATC module