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Home >> Dodge and Ram >> 2023 >> ProMaster 2500 >> Repair and Diagnosis >> Accessories & Equipment >> Communication Devices >> Body Control Module (BCM) - DTCS U170-86 To U1935-8F >> DTC Troubleshooting >> U1801-08-Lin 1 - Bus Signal/Message Failures >> Diagnostic Test

Diagnostic Test

  1. CHECK FOR AN ACTIVE DTC 
    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. Using the recorded Environmental Data, along with the When Monitored and Set Conditions above, operate the vehicle in the conditions that set the DTC.
    5. With the scan tool, read BCM DTCs.

      Did the DTC return?

      Yes 

      • Go To  2

      No 

  2. CHECK THE HUMIDITY RAIN LIGHT SENSOR (HRLS) FOR AN INTERNAL SHORT 
    1. Turn the ignition off.
    2. Disconnect the HRLS harness connector.
    3. Turn the ignition on.
    4. Wait 10 seconds.
    5. With the scan tool, read the BCM DTCs.

      Is the DTC active?

      Yes 

      • Go To  3

      No 

      • Replace the Humidity Rain Light Sensor (HRLS) in accordance with the Service Information.
      • Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
  3. CHECK THE (D401) LIN BUS 1 CIRCUIT FOR A SHORT TO VOLTAGE 
    1. Turn the ignition off.
    2. Disconnect the BCM harness connector containing the (D401) LIN Bus 1 circuit.
    3. Turn the ignition on.
    4. Measure the voltage on the (D401) LIN Bus 1 circuit at the BCM harness connector.

      Is there any voltage present?

      Yes 

      • Repair the short to voltage on the (D401) LIN Bus 1 circuit.
      • Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .

      No 

      • Go To  4
  4. CHECK THE (D401) LIN BUS 1 CIRCUIT FOR A SHORT TO GROUND 
    1. Turn the ignition off.
    2. Check for continuity between ground and the (D401) LIN Bus 1 circuit at the BCM harness connector.

      Is there continuity between ground and the (D401) LIN Bus 1 circuit?

      Yes 

      • Repair the short to ground in the (D401) LIN Bus 1 circuit.
      • Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .

      No 

      • Go To  5
  5. CHECK RELATED HARNESS CONNECTIONS 
    1. Disconnect all BCM 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 BCM 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