Test C: The Electronic Automatic Temperature Control (EATC) Module Does Not Respond to the Diagnostic Tool
PINPOINT TEST C: THE ELECTRONIC AUTOMATIC TEMPERATURE CONTROL (EATC) MODULE DOES NOT RESPOND TO THE DIAGNOSTIC TOOLC1-C2:
C3:
Normal Operation
The EATC module communicates with the diagnostic tool through the universal asynchronous receiver-transmitter (UART) based protocol (UBP) communications network, circuit 693 (OG). Check circuit 693 (OG) between the EATC module C228b and the data link connector (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 in the UBP network circuit, damage to the DLC C251, damage to the EATC module C228b, or a problem in an in-line connector.
Possible Causes
- UBP communications network, circuit 693 (OG) open
- EATC module C228b
- EATC module