Test F: The Dual Automatic Temperature Control (DATC) Module Does Not Respond To The Diagnostic Tool

PINPOINT TEST F: THE DUAL AUTOMATIC TEMPERATURE CONTROL (DATC) MODULE DOES NOT RESPOND TO THE DIAGNOSTIC TOOL

F1-F3:

F3-F4:

F4-F5:

Normal Operation
The DATC module communicates with the diagnostic tool through the standard corporate protocol (SCP) communications network circuit 4-FA10 (GY/BK) and 5-FA10 (BU/YE). If one of the communications network circuits becomes shorted to ground or voltage, or if some but not all termination resistors are lost, communications can continue. Check circuits 4-FA10 (GY/BK) and 5-FA10 (BU/YE) between the DATC module C228a 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 circuits 4-FA10 (GY/BK) or 5-FA10 (BU/YE), damage to the DLC C251, the DATC module C228a, or in joint connector No. 4 C223.

Possible Causes
- SCP data plus circuit 4-FA10 (GY/BK) open
- SCP data minus circuit 5-FA10 (BU/YE) open
- joint connector No. 4 C223
- DATC module C228a
- DATC module