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Home >> Alfa Romeo >> 2019 >> Giulia Base, AWD >> Repair and Diagnosis >> Accessories & Equipment >> Communication Devices >> Body Control Module (BCM) - DTCS B12AE-15 To U1702-87 >> DTC Troubleshooting >> U1418-87-HRLS (Humidity Rain Light Solar Module)-Missing Message >> 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 FOR ADDITIONAL DTCS IN THE HVAC MODULE 
    1. With the scan tool, read HVAC Module DTCs.

      Are any Humidity, Light or Solar related DTCs set?

      Yes 

      No 

      • Go To  3
  3. CHECK THE (F926) FUSED IGNITION SWITCH OUTPUT (RUN) CIRCUIT FOR VOLTAGE 
    1. Turn the ignition off.
    2. Disconnect the Rain Sensor harness connector.
    3. Turn the ignition on.
    4. Measure the voltage on the (F926) Fused Ignition Switch Output (Run) circuit at the Rain Sensor harness connector.

      Is the voltage above 9.0 volts?

      Yes 

      • Go To  4

      No 

      • Repair the open or short to ground in the (F926) Fused Ignition Switch Output (Run) circuit.
      • Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
  4. CHECK THE (Z332) GROUND CIRCUIT FOR AN OPEN 
    1. Turn the ignition off.
    2. Measure the resistance between ground and the (Z332) Ground circuit at the Rain Sensor harness connector.

      Is the resistance above 3.0 Ohms?

      Yes 

      • Repair the open in the (Z332) Ground circuit.
      • Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .

      No 

      • Go To  5
  5. CHECK THE (D401) LIN BUS 1 CIRCUIT FOR VOLTAGE 
    1. Turn the ignition on.
    2. Measure the voltage on the (D401) LIN Bus 1 circuit at the Rain Sensor harness connector.

      Is there any voltage present?

      Yes 

      • Replace the Rain Sensor in accordance with the Service Information.
      • Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .

      No 

      • Go To  6
  6. CHECK THE (D401) LIN BUS 1 CIRCUIT FOR AN OPEN 
    1. Turn the ignition off.
    2. Disconnect the BCM C6/F harness connector.
    3. Measure the resistance of the (D401) LIN Bus 1 circuit between the Rain Sensor harness connector and BCM C6/F harness connector - terminal 2.

      Is the resistance above 3.0 Ohms?

      Yes 

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

      No 

      • Go To  7
  7. 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. Connect all BCM harness connectors. Be certain that all harness connectors are fully seated and the connector locks are fully engaged.
    6. Connect all in-line harness connectors (if equipped). Be certain that all connectors are fully seated and the connector locks are fully engaged.
    7. Connect 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