Jump to content
  • P0642 Low Voltage At The #2 Sensor Supply Circuit

       (1 review)

    Mopar1973Man

    P0642 LOW VOLTAGE AT THE #2 SENSOR SUPPLY CIRCUIT

    When Monitored and Set Condition:

    When Monitored: With the key on.
    Set Condition: Voltage detected on the #2 sensor supply circuit is below a calibrated value.

    • POSSIBLE CAUSES
    • FAN CLUTCH ASSEMBLY
    • (F856) 5-VOLT SHORTED TO GROUND
    • (F856) 5-VOLT SUPPLY SHORTED TO ANOTHER CIRCUIT
    • FAN DTC
    • INTERMITTENT CONDITION
    • ECM

    DIAGNOSTIC PROCEDURE

    1. Disconnect the Fan clutch harness connector.
      NOTE: Check connectors - Clean/repair as necessary.
      With the DRBIII®, read DTCs. Did P0483 set?
      Yes --> Replace the Fan clutch assembly. Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL).
      No --> Go To 2
    2. Turn the ignition off. Disconnect the ECM harness connector.
      NOTE: Check connectors - Clean/repair as necessary.
      Measure the resistance between the (F856) #2 5-volt supply (fan speed sensor power) circuit in the sensor harness connector and battery negative. Is the resistance greater than 100k Ohms?
      Yes --> Go To 3
      No --> Repair the #2 (F856) 5-volt supply shorted to ground. Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL).
    3. Measure the resistance between the sensor (F856) #2 5-volt supply (fan speed sensor power) circuit in the ECM harness connector to all other circuits in the ECM harness connectors Is the resistance greater than 100k Ohms?
      Yes --> Go To 4
      No --> Repair the 5-volt supply shorted to another circuit. Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL).
    4. Reconnect the ECM harness connectors. Reconnect the disconnected Fan harness connector. Turn the ignition on. With the DRBIII®, read DTCs. Is DTC P0483 set?
      Yes --> Repair the Fan DTC. Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL).
      No --> Go To 5
    5. Turn the ignition off. Disconnect the Fan harness connector. Turn the ignition on. Measure the voltage between the sensor (F856) #2 5-volt supply (fan speed sensor power) circuit at the fan clutch harness connector and the fan speed sensor ground. Is the voltage between 4.5 and 5.5 volts?
      Yes --> Refer to the SYMPTOM: INTERMITTENT CONDITION Symptom (Diagnostic Procedure). Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL).
      No --> Replace the ECM. Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL).

    User Feedback


    officerjones85

       1 of 1 member found this review helpful 1 / 1 member

    This is awesome. Thank you for Ohms as well.

    • Like 2
    Link to review
    Share on other sites


×
×
  • Create New...

Advertisements and Ad Blockers

Mopar1973Man.Com uses the income from advertisers to pay the bills on the website. Please whitelist your ad blockers for Mopar1973Man.Com this will allow advertisements to display on our pages but allows you to still block ads on the other websites you visit. 

 

image.png

I will whitelist Mopar1973Man.Com