Electronic Automatic Temperature Control (EATC) Module
WARNING: This page is about a different car, the 2006 Mercury Mountaineer and 2006 Ford Explorer. However, it is still accessible from the selected car via links, so may be relevant.
The EATC module (if equipped) uses the medium speed CAN for communication with the diagnostic tool and other modules on the medium speed CAN. The EATC module controls the automatic climate functions that maintain the vehicle interior temperature at a constant setting.
Check the medium speed CAN circuits between the EATC module C228a and the 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 circuit in the medium speed CAN, damage to the DLC C251, damage to the EATC module C228a, or a problem to an in-line connector.
For additional EATC module information, refer to CLIMATE CONTROL SYSTEM-GENERAL INFORMATION AND DIAGNOSTICS .