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

WARNING: This page is about a different car, the 2004 Mercury Monterey and 2004 Ford Freestar. However, it is still accessible from the selected car via links, so may be relevant.

C1 CHECK FOR AN OPEN BETWEEN THE DLC C251 AND THE PCM C175a
- Key in OFF position.
- Disconnect: PCM C175.
- Measure the resistance between the PCM C175-15, circuit 915 (PK/LB), harness side and the DLC C251-10, circuit 915 (PK/LB), harness side.
  
  Fig 1: Measuring Resistance Between The PCM C175-15, Circuit 915 (PK/LB), Harness Side And The DLC C251-10, Circuit 915 (PK/LB), Harness Side
  Courtesy of FORD MOTOR CO.
- Measure the resistance between the PCM C175-16, circuit 914 (TN/OG), harness side and the DLC C251-2, circuit 914 (TN/OG), harness side.
  
  Fig 2: Measuring Resistance Between The PCM C175-15, Circuit 915 (PK/LB), Harness Side And The DLC C251-10, Circuit 915 (PK/LB), Harness Side
  Courtesy of FORD MOTOR CO.
- Are the resistances less than 5 ohms?
Yes

GO to C2

No

REPAIR the circuit in question. CLEAR the DTCs. REPEAT the self-test. CARRY OUT the data link diagnostics test.
C2 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 INTAKE AIR, FUEL CHARGING, & ENGINE ELECTRONICS CLEAR the DTCs REPEAT the self-test. CARRY OUT the data link diagnostics 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 data link diagnostics test.