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

WARNING: This page is about a different car, the 2006 Mercury Grand Marquis and 2006 Ford Crown Victoria. However, it is still accessible from the selected car via links, so may be relevant.

CAUTION: Use the correct probe adaptor(s) when making measurements. Failure to use the correct probe adaptor(s) may damage the connector.

D1 CHECK THE EATC MODULE C228A FOR DAMAGE
- Key in OFF position.
- Disconnect: EATC Module C228a.
- Inspect the EATC module C228a for damage.
- Is the EATC module C228a OK?
Yes : GO to D2.

No : REPAIR the EATC C228a as necessary. CARRY OUT the diagnostic tool data link test.
D2 CHECK THE SCP CIRCUITS BETWEEN THE DLC AND THE EATC MODULE FOR AN OPEN
- Measure the resistance between the EATC module C228a-15, circuit 914 (TN/OG), harness side and the DLC C251-2, circuit 914 (TN/OG), harness side.
  
  Fig 1: Checking The SCP Circuits Between The DLC And The EATC Module For An Open (1 Of 2)
  Courtesy of FORD MOTOR CO.
- Measure the resistance between the EATC module C228a-1, circuit 915 (PK/LB), harness side and the DLC C251-10, circuit 915 (PK/LB), harness side.
  
  Fig 2: Checking The SCP Circuits Between The DLC And The EATC Module For An Open (2 Of 2)
  Courtesy of FORD MOTOR CO.
- Are the resistances less than 5 ohms?
Yes : GO to D3.

No : REPAIR the circuit. CARRY OUT the diagnostic tool data link test.
D3 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 climate control assembly. REFER to CLIMATE CONTROL . CLEAR the diagnostic trouble codes (DTCs). REPEAT the self-test. CARRY OUT the diagnostic tool data link test.

No : The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. CLEAR the DTCs. REPEAT the self-test.