Pinpoint Test B: The Powertrain Control Module (Pcm) 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.

B1 CHECK THE PCM C175B FOR DAMAGE
- 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. CARRY OUT the diagnostic tool data link test.
B2 CHECK THE CAN CIRCUITS BETWEEN THE PCM AND THE DLC FOR AN OPEN
- Measure the resistance between the PCM C175b-11, circuit 1827 (WH/LG), harness side and the DLC C251-6, circuit 1827 (WH/LG), harness side.
  
  Fig 1: Checking The CAN Circuits Between The PCM And The DLC For An Open (1 Of 2)
  Courtesy of FORD MOTOR CO.
- Measure the resistance between the PCM C175b-23, circuit 1828 (PK/LG), harness side and the DLC C251-14, circuit 1828 (PK/LG), harness side.
  
  Fig 2: Checking The CAN Circuits Between The PCM And The DLC For An Open (2 Of 2)
  Courtesy of FORD MOTOR CO.
- Are the resistances less than 5 ohms?
Yes : GO to B3.

No : REPAIR the circuit. CARRY OUT the diagnostic tool data link 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 . 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. CARRY OUT the diagnostic tool data link test.