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

WARNING: This page is about a different car, the 2005 Ford RV Cutaway, 2005 Ford Econoline, 2005 Ford E450 Super Duty, and 2005 Ford Cutaway. However, it is still accessible from the selected car via links, so may be relevant.

A1 CHECK FOR AN OPEN BETWEEN THE PCM AND THE DATA LINK CONNECTOR (DLC) C251
- Key in OFF position.
- Disconnect: PCM C175 (Gasoline).
- Disconnect: PCM C176a (Diesel).
- On gasoline engines, measure the resistance between the PCM C175-11, circuit 1827 (WH/LG), harness side and DLC C251-6, circuit 1827 (WH/LG), harness side.
  
  Fig 1: Measuring Resistance Between PCM Circuit 1827 And Harness Side
  Courtesy of FORD MOTOR CO.
- On gasoline engines, measure the resistance between the PCM C175-23, circuit 1828 (PK/LG), harness side and DLC C251-14, circuit 1828 (PK/LG), harness side.
  
  Fig 2: Measuring Resistance Between Circuit 1828 And Harness Side
  Courtesy of FORD MOTOR CO.
- On diesel engines, measure the resistance between the PCM C176a-13, circuit 1827 (WH/LG), harness side and DLC C251-6, circuit 1827 (WH/LG), harness side.
  
  Fig 3: Measuring Resistance Between Circuit 1827 And Harness Side
  Courtesy of FORD MOTOR CO.
- On diesel engines, measure the resistance between the PCM C176a-14, circuit 1828 (PK/LG), harness side and DLC C251-14, circuit 1828 (PK/LG), harness side.
  
  Fig 4: Measuring Resistance Between Circuit 1828 And Harness Side
  Courtesy of FORD MOTOR CO.
- Are the resistances less than 5 ohms?
- Yes : GO to A2.
- No : REPAIR the circuit in question. CLEAR the diagnostic trouble codes (DTCs). REPEAT the self-test. CARRY OUT the diagnostic tool data link test.
A2 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 - GASOLINE ENGINES or ELECTRONIC ENGINE CONTROLS - GASOLINE ENGINES . CLEAR the 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.