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

WARNING: This page is about a different car, the 2004 Lincoln LS. However, it is still accessible from the selected car via links, so may be relevant.

Test Step

H1 CHECK THE PCM C175a FOR DAMAGE
- Key in OFF position.
- Disconnect: PCM C175a.
- Inspect the PCM C175a for damage.
- Is the PCM C175 a OK?
Result / Action to Take
1. Yes : GO to H2.
2. No : REPAIR the PCM C175a as necessary. TEST the system for normal operation.
H2 CHECK FOR AN OPEN BETWEEN THE DLC C251 AND THE PCM C175a
- Measure the resistance between the PCM C175a-53, circuit 4-EC7 (GY/RD), harness side and the DLC C251 -6, circuit 4-EC7 (GY/RD), harness side.
  
  Fig 1: Checking For An Open Between The DLC C251 And The PCM C175A (1 Of 2)
  Courtesy of FORD MOTOR CO.
- Measure the resistance between the PCM C175a-54, circuit 5-EC7 (BU/RD), harness side and the DLC C251 -14, circuit 5-EC7 (BU/RD), harness side.
  
  Fig 2: Checking For An Open Between The DLC C251 And The PCM C175A (2 Of 2)
  Courtesy of FORD MOTOR CO.
- Are the resistances less than 5 ohms?
1. Yes : GO to H3.
2. No : REPAIR the circuit in question. TEST the system for normal operation.
H3 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?
1. Yes : INSTALL a new PCM. REFER to INTAKE AIR, FUEL CHARGING, STARTING & ENGINE ELECTRONICS - 3.0L (4V) - LS or INTAKE AIR, FUEL CHARGING, STARTING & ENGINE ELECTRONICS - 3.9L - LS .TEST the system for normal operation.
  CARRY OUT the PINPOINT TEST PC: data link diagnostics network test .
2. 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.