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Pinpoint Test C : P0620

NOTE: Make sure battery voltage is greater than 12.2 volts prior to and during this pinpoint test.
NOTE: Do not have a battery charger attached during vehicle testing.

  1. C1 PERFORM INSPECTION AND VERIFICATION

    Was an obvious cause for an observed or reported concern found? 

    Yes  CORRECT conditions as necessary.
    No  GO to  C2.
  2. C2 CHECK THE GENERATOR CONNECTIONS

    • Ignition OFF.
    • Disconnect and inspect all generator connectors.
    • Repair:
      • corrosion (install new connector or terminals - clean module pins)
      • damaged or bent pins - install new terminals/pins
      • pushed-out pins - install new pins as necessary
    • Measure and record:
      Positive Lead Measurement / Action Negative Lead
      GFD35485Courtesy of FORD MOTOR COMPANY

      Battery Positive Post
      GFD33595Courtesy of FORD MOTOR COMPANY
      GFD37006Courtesy of FORD MOTOR COMPANY

      Battery Negative Post
    • Measure:
      Positive Lead Measurement / Action Negative Lead
      C102B-1
      GFD33595Courtesy of FORD MOTOR COMPANY
      Ground

    Is the voltage within 0.5 volt of recorded battery voltage? 

    Yes  GO to  C3.
    No  VERIFY the fusible links are OK. If OK, REPAIR the circuit. If not OK, REFER to the SYSTEM WIRING DIAGRAMS article to identify the Possible Sources of the circuit short.
  3. C3 CHECK THE VOLTAGE DROP IN THE B+ CIRCUIT

    • Start the engine.
    • With the engine running at idle, headlamps on and blower on high, measure:
      Positive Lead Measurement / Action Negative Lead
      C102B-1
      GFD33595Courtesy of FORD MOTOR COMPANY
      GFD35485Courtesy of FORD MOTOR COMPANY

      Battery Positive Post
    • Carry out a wiggle test of the generator wiring and connections while measuring voltage drop.

    Is the voltage drop less than 0.5 volt? 

    Yes  GO to  C4.
    No  INSPECT and REPAIR any corrosion in the generator B+ circuit or positive battery cable connections.
  4. C4 "A" SENSE CIRCUIT LOAD TEST

    NOTE: The following step uses a test light to simulate normal circuit loads. Use only the test light recommended. To avoid connector terminal damage, use the Flex Probe Kit for the test light probe connection to the vehicle. Do not use the test light probe directly on any connector.
    NOTE: This step puts a load on the "A" sense circuit. If there are corroded or loose connections, loading the circuit may help show the fault. A 250-350 mA incandescent 12-volt test lamp is required for this step. This circuit cannot be loaded correctly using an LED-style test lamp.
    • Ignition OFF.
    • Disconnect: Generator C102A .
    • Measure battery voltage and record:
      Positive Lead Measurement / Action Negative Lead
      GFD35485Courtesy of FORD MOTOR COMPANY

      Battery Positive Post
      GFD33595Courtesy of FORD MOTOR COMPANY
      GFD37006Courtesy of FORD MOTOR COMPANY

      Battery Negative Post
    • Ignition ON.
    • Using a 12-volt test lamp connected to ground, while performing a wiggle test on the generator harness, measure voltage at:
      Positive Lead Measurement / Action Negative Lead
      C102A-3 Test Lamp Ground

    Is the "A" sense voltage equal to battery voltage? 

    Yes  GO to  C5.
    No  VERIFY BJB fuse 58 (10A) is OK. If OK, REPAIR the circuit. If not OK, REFER to the SYSTEM WIRING DIAGRAMS article to identify the Possible Sources of the circuit short.
  5. C5 CHECK THE GENERATOR COMMAND CIRCUIT FOR A SHORT TO VOLTAGE

    • Ignition OFF.
    • Disconnect: PCM C175B (3.5L Ti-VCT) or C1381B (2.0L GTDI) or C155B (3.5L GTDI).
    • Ignition ON.
    • Measure:
      Positive Lead Measurement / Action Negative Lead
      C102A-2
      GFD33595Courtesy of FORD MOTOR COMPANY
      Ground

    Is any voltage present? 

    Yes  REPAIR the circuit.
    No  GO to  C6.
  6. C6 CHECK THE GENERATOR COMMAND CIRCUIT FOR A SHORT TO GROUND

    • Ignition OFF.
    • Measure:
      Positive Lead Measurement / Action Negative Lead
      C102A-2
      GFD33596Courtesy of FORD MOTOR COMPANY
      Ground

    Is the resistance greater than 10, 000 ohms? 

    Yes  GO to  C7.
    No  REPAIR the circuit.
  7. C7 CHECK THE GENERATOR COMMAND CIRCUIT FOR AN OPEN

    • Ignition OFF.
    • 3.5L Ti-VCT engine, measure:
      Positive Lead Measurement / Action Negative Lead
      C175B-53
      GFD33596Courtesy of FORD MOTOR COMPANY
      C102A-2
    • 2.0L GTDI engine, measure:
      Positive Lead Measurement / Action Negative Lead
      C1381E-90
      GFD33596Courtesy of FORD MOTOR COMPANY
      C102A-2
    • 3.5L GTDI engine, measure:
      Positive Lead Measurement / Action Negative Lead
      C1551B-59
      GFD33596Courtesy of FORD MOTOR COMPANY
      C102A-2

    Is the resistance less than 3 ohms? 

    Yes  GO to  C8.
    No  REPAIR the circuit.
  8. C8 COMPARE THE GENERATOR MONITOR (GENMON) AND GENERATOR COMMAND (GENCMD) PIDs

    • Ignition OFF.
    • Connect: PCM C175B (3.5L Ti-VCT) or C1381B (2.0L GTDI) or C155B (3.5L GTDI).
    • Connect a fused jumper wire:
      Positive Lead Measurement / Action Negative Lead
      C102A-1
      GFD33601Courtesy of FORD MOTOR COMPANY
      C102A-2
    • Start the engine.
    • Using a scan tool, view the PCM PIDs.
    • Monitor the PCM PIDs GENMON and GENCMD while performing a wiggle test on the generator harness.

    Do the PIDs read within 5% of each other? 

    Yes  REMOVE the fused jumper wire. INSTALL a new generator. REFER to Generator - 2.0L GTDI  or REFER to Generator - 3.5L GTDI  or REFER to Generator - 3.5L Ti-VCT .
    No  REMOVE the fused jumper wire. GO to  C9.
  9. C9 CHECK FOR CORRECT PCM OPERATION

    • Ignition OFF.
    • Disconnect and inspect all PCM connectors.
    • Repair:
      • corrosion (install new connector or terminals - clean module pins)
      • damaged or bent pins - install new terminals/pins
      • pushed-out pins - install new pins as necessary
    • Reconnect the PCM and generator connectors. Make sure they seat and latch correctly.
    • Operate the system and determine if the concern is still present.

    Is the concern still present? 

    Yes  CHECK OASIS for any applicable TSBs. If a TSB exists for this concern, DISCONTINUE this test and FOLLOW the TSB instructions. If no TSBs address this concern, INSTALL a new PCM. REFER to Electronic Engine Controls - 2.0L GTDI or REFER to Electronic Engine Controls - 3.5L GTDI or REFER to Electronic Engine Controls - 3.5L Ti-VCT
    No  The system is operating correctly at this time. The concern may have been caused by module connections. ADDRESS the root cause of any connector or pin issues.