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Home >> Dodge and Ram >> 2023 >> ProMaster 2500 >> Repair and Diagnosis >> Accessories & Equipment >> Communication Devices >> Body Control Module (BCM) - DTCS B1856-13 To U1701-87 >> DTC Troubleshooting >> U0401-64-Implausible Data Received From Engine Control Module (ECM) - Signal Plausibility Failure >> Diagnostic Test

Diagnostic Test

  1. CHECK FOR AN ACTIVE DTC 
    WARNING:

    When the engine is operating, do not stand in direct line with the fan. Do not put your hands near the pulleys, belts or fan. Do not wear loose clothing. Failure to follow these instructions may result in possible serious or fatal injury.

    1. With the scan tool, read Body Control Module (BCM) DTCs and record on the repair order.
    2. Record the Environmental Data.
    3. With the scan tool, erase DTCs.
    4. Attempt to crank the engine.
    5. With the scan tool, read BCM DTCs.

      Did the DTC return?

      Yes 

      • Go To  2

      No 

  2. CHECK FOR POWERTRAIN CONTROL MODULE (PCM) DTCS 
    1. With the scan tool, read the PCM DTCs and record on the repair order.

      Are there any Starter Relay related DTCs active?

      Yes 

      No 

      • Go To  3
  3. CHECK THE STARTER RELAY 
    1. Turn the ignition off.
    2. Remove the Starter Relay from the Power Distribution Center (PDC) Assembly and substitute it with a known good relay.
      WARNING:

      When the engine is operating, do not stand in direct line with the fan. Do not put your hands near the pulleys, belts or fan. Do not wear loose clothing. Failure to follow these instructions may result in possible serious or fatal injury.

    3. Attempt to crank the engine.

      Does the engine crank?

      Yes 

      No 

      • Go To  4
  4. CHECK THE (T752) STARTER RELAY OUTPUT CIRCUIT FOR AN OPEN 
    1. Turn the ignition off.
    2. Remove the Starter Relay from the PDC Assembly.
    3. Disconnect the PCM C1 harness connector.
    4. Measure the resistance of the (T752) Starter Relay Output circuit between the PCM C1 harness connector and the Starter Relay terminal in the PDC Assembly.

      Is the resistance above 3.0 Ohms?

      Yes 

      • Repair the open in the (T752) Starter Relay Output circuit.
      • Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .

      No 

      • Go To  5
  5. CHECK THE PDC ASSEMBLY 
    1. Disconnect the PDC Assembly C1 harness connector.
    2. Measure the resistance of the (T752) Starter Relay Output circuit between the PDC Assembly C1 harness connector and the Starter Relay terminal in the PDC Assembly.

      Is the resistance above 3.0 Ohms?

      Yes 

      • Check the PDC Assembly connectors for signs of water intrusion, corrosion, pushed out or bent terminals and correct pin tension. If no problems are found, replace the Power Distribution Center (PDC) Assembly in accordance with the Service Information.
      • Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .

      No 

      • Go To  6
  6. CHECK RELATED HARNESS CONNECTIONS 
    1. Disconnect all PCM harness connectors.
    2. Disconnect all related in-line harness connections (if equipped).
    3. Disconnect the related component harness connectors.
    4. Inspect harness connectors, component connectors, and all male and female terminals for the following conditions:
      • Proper connector installation.
      • Damaged connector locks.
      • Corrosion.
      • Other signs of water intrusion.
      • Weather seal damage (if equipped).
      • Bent terminals.
      • Overheating due to a poor connection (terminal may be discolored due to excessive current draw).
      • Terminals that have been pushed back into the connector cavity.
      • Perform a terminal drag test on each connector terminal to verify proper terminal tension.

      Repair any conditions that are found.

    5. Reconnect all PCM harness connectors. Be certain that all harness connectors are fully seated and the connector locks are fully engaged.
    6. Reconnect all in-line harness connectors (if equipped). Be certain that all connectors are fully seated and the connector locks are fully engaged.
    7. Reconnect all related component harness connectors. Be certain that all connectors are fully seated and the connector locks are fully engaged.
    8. With the scan tool, erase DTCs.
    9. Using the recorded Environmental Data, along with the When Monitored and Set Conditions above, operate the vehicle in the conditions that set the DTC.
    10. With the scan tool, read BCM DTCs.

      Did the DTC return?

      Yes 

      No