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Home >> Subaru >> 2017 >> Outback 2.5i >> Repair and Diagnosis (Single Page) >> Engine Performance >> System >> Engine Control System (Diagnostics) (P2101 To U1712) (H4DO) >> Diagnostic Procedure with Diagnostic Trouble Code (DTC) >> DTC U0284: Lost Communication With Active Grille Shutter Module "A" >> Notes

DTC U0284: Lost Communication With Active Grille Shutter Module "A": Notes

DTC detecting condition: 

Immediately at fault recognition

CAUTION:
  • After servicing or replacing faulty parts, perform Clear Memory Mode Ref. to OPERATION , Clear Memory Mode.>, and Inspection Mode Ref. to PROCEDURE , Inspection Mode.>.
  • Use the check board when measuring the ECM terminal voltage and resistance.

Wiring diagram: 

Active grille shutter Ref. to ACTIVE GRILLE SHUTTER .>

Fig 1: Lost Communication With Active Grille Shutter Module "A" - Wiring Diagram
G11583422Courtesy of SUBARU OF AMERICA, INC.
Step Check Yes No
1 CHECK DTC. 
Check for DTC. Ref. to READ DIAGNOSTIC TROUBLE CODE (DTC) .>		 Is U0284 displayed in current malfunction? Go to step 2  . The circuit has returned to a normal condition at this time. Reproduce the failure, and then perform the diagnosis again.
NOTE: In this case, temporary poor contact of connector, temporary open or short circuit of harness may be the cause.
2 CHECK FOR ANY OTHER DTC ON DISPLAY.  Is any other DTC displayed for engine control system? Check the appropriate DTC using the "List of Diagnostic Trouble Code (DTC)". Ref. to LIST OF DIAGNOSTIC TROUBLE CODE (DTC) .> Go to step 3  .
3 CHECK HARNESS BETWEEN ECM AND ACTIVE GRILLE SHUTTER CONNECTOR. 
  1. Turn the ignition switch to OFF.
  2. Disconnect the battery.
  3. Disconnect the connector from ECM.
  4. Disconnect the connector from the active grille shutter.
  5. Measure the resistance between active grille shutter connector and chassis ground.

Connector & terminal 
(B63) No. 3 - Chassis ground: 		 Is the resistance 1 MΩ or more? Go to step 4  . Repair the short circuit to ground in harness between ECM and active grille shutter connector.
4 CHECK HARNESS BETWEEN ECM AND ACTIVE GRILLE SHUTTER CONNECTOR. 
Measure the resistance of harness between ECM and active grille shutter connector.
Connector & terminal 
(B134) No. 55 - (B63) No. 3: 		 Is the resistance less than 10 Ω? Go to step 5  . Repair the harness and connector.
NOTE: In this case, repair the following item:
  • Open circuit of harness between ECM and active grille shutter connector
  • Poor contact of coupling connector
5 CHECK ACTIVE GRILLE SHUTTER POWER SUPPLY. 
  1. Connect the battery.
  2. Measure the voltage between active grille shutter connector and chassis ground.

Connector & terminal 
(B63) No. 2 (+) - Chassis ground (-): 		 Is the voltage 9 V or more? Go to step 6  . Repair the power supply circuit.
6 CHECK HARNESS BETWEEN ACTIVE GRILLE SHUTTER CONNECTOR AND CHASSIS GROUND. 
Measure the resistance of harness between active grille shutter connector and chassis ground.
Connector & terminal 
(B63) No. 4 - Chassis ground: 		 Is the resistance less than 10 Ω? Replace the active grille shutter. Repair the harness and connector.
NOTE: In this case, repair the following item:
  • Open circuit of harness between active grille shutter connector and chassis ground
  • Poor contact of coupling connector
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