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

B1 CHECK EATC MODULE C228 FOR DAMAGE
- Key in OFF position.
- Disconnect: EATC Module C228.
- Inspect the EATC module C228 for damage.
- Is the EATC module C228 OK?
- Yes : GO to B2.
- No : REPAIR the EATC module C228. CARRY OUT the diagnostic tool data link test.
B2 CHECK MEDIUM SPEED CAN CIRCUITS 1827 (WH/LG) AND 1828 (PK/LG) BETWEEN DLC C251 AND EATC MODULE C228 FOR OPEN
- Measure the resistance between the EATC module C228 pin 7, circuit 1827 (WH/LG), harness side and the DLC C251 pin 3, circuit 1827 (WH/LG), harness side; and between the EATC module C228 pin 8, circuit 1828 (PK/LG), harness side and the DLC C251 pin 11, circuit 1828 (PK/LG), harness side.
  
  Fig 1: Checking Medium Speed CAN Circuits 1827 (WH/LG) And 1828 (PK/LG) Between DLC C251 And EATC Module C228 For Open
  Courtesy of FORD MOTOR CO.
- Are the resistances less than 5 ohms?
- Yes : GO to B3.
- No : REPAIR the circuit in question. CLEAR the DTCs. REPEAT the self-test. CARRY OUT the diagnostic tool data link test.
B3 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 CLIMATE CONTROL SYSTEM-GENERAL INFORMATION . CLEAR the DTCs. REPEAT the self-test. CARRY OUT the diagnostic tool data link test.
- No : The system is operating correctly at this time. Concern may have been caused by a loose or corroded connector. CLEAR the DTCs. REPEAT the self-test. CARRY OUT the diagnostic tool data link test.