Pinpoint Test B: The Powertrain Control Module (Pcm) Does Not Respond To The Diagnostic Tool

WARNING: This page is about a different car, the 2005 Ford Pickup. However, it is still accessible from the selected car via links, so may be relevant.

B1 CHECK THE PCM C175B
- Key in OFF position.
- Disconnect: PCM C175b.
- Inspect the PCM C175b for damage.
- Is the PCM C175b OK?
- Yes : GO to B2.
- No : REPAIR the PCM C175b as necessary. CARRY OUT the data link diagnostics test.
B2 CHECK CIRCUITS 1827 (WH/LG) AND 1828 (PK/LG) BETWEEN THE PCM C175B AND THE DLC C251 FOR AN OPEN
- Measure the resistance between the PCM C175b-2, circuit 1827 (WH/LG), harness side and the data link connector (DLC) C251-6, circuit 1827 (WH/LG), harness side.
  
  Fig 1: Checking Circuits 1827 (WH/LG) And 1828 (PK/LG) Between PCM C175b And DLC C251 For An Open
  Courtesy of FORD MOTOR CO.
- Measure the resistance between the PCM C175b-3, circuit 1828 (PK/LG), harness side and the DLC C251-14, circuit 1828 (PK/LG), harness side.
  
  Fig 2: Measuring Resistance Between PCM C175b-3, Circuit 1828 (PK/LG), Harness Side And DLC C251-14, Circuit 1828 (PK/LG), Harness Side
  Courtesy of FORD MOTOR CO.
- Are the resistances less than 5 ohms?
- Yes : GO to B3.
- No : REPAIR the circuit in question. CARRY OUT the data link diagnostics test.
B3 CHECK FOR CORRECT PCM OPERATION
- Disconnect all the PCM connectors.
- Check for:
  - Corrosion
  - Push-out pins
- Connect all the PCM 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 PCM. REFER to ELECTRONIC ENGINE CONTROLS . 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. CARRY OUT the data link diagnostics test.