Pinpoint Test C: The Electronic Automatic Temperature Control (EATC) Module Does Not Respond To The Diagnostic Tool

WARNING: This page is about a different car, the 2005 Ford Pickup, 2005 Ford F550 Super Duty, 2005 Ford F450 Super Duty, and 2005 Ford Cab & Chassis. However, it is still accessible from the selected car via links, so may be relevant.

C1 CHECK THE EATC MODULE C228B FOR DAMAGE
- Key in OFF position.
- Disconnect: EATC Module C228b.
- Inspect the EATC module C228b for damage.
- Is the EATC module C228b OK?
- Yes : GO to C2.
- No : REPAIR the EATC module C228b as necessary. CARRY OUT the data link diagnostics test.
C2 CHECK CIRCUIT 693 (OG) FOR AN OPEN BETWEEN THE DATA LINK CONNECTOR (DLC) C251 AND THE EATC C228B
- Measure the resistance between the EATC module C228b pin 3, circuit 693 (OG), harness side and the DLC C251 pin 3, circuit 693 (OG), harness side.
  
  Fig 1: Check Circuit 693 (OG) For An Open Between The Data Link Connector (DLC) C251 & The EATC C228B
  Courtesy of FORD MOTOR CO.
- Is the resistance less than 5 ohms?
- Yes : GO to C3.
- No : REPAIR the circuit. CARRY OUT the data link diagnostics test.
C3 CHECK FOR CORRECT EATC MODULE OPERATION
- Disconnect all the EATC module connectors.
- Check for:
  - corrosion
  - pushed-out pins
- Connect all the EATC module connectors and make sure they seat correctly.
- Operate the system and verify the concern is still present.
- Is the concern still present?
- Yes : INSTALL a new EATC module. REFER to CONTROL COMPONENTS . CARRY OUT the data link diagnostics test.
- No : The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. CLEAR the diagnostic trouble codes (DTCs). REPEAT the self-test.