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HOMESERVICE MANUALSSUBARU2016LEGACY 2.5IREPAIR AND DIAGNOSISACCESSORIES & EQUIPMENTCOMMUNICATION DEVICESLAN COMMUNICATION SYSTEM (DIAGNOSTICS)DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)DTC U0420 INVALID DATA RECEIVED FROM POWER STEERING CONTROL MODULETROUBLE SYMPTOM
2016 Subaru Legacy 2.5i

DTC U0420 Invalid Data Received From Power Steering Control Module: Trouble Symptom

2016 Subaru Legacy 2.5iSECTION Trouble Symptom

Cooperation control with EPS control module does not operate properly.

DIAGNOSTICS PROCEDURE

Step Check Yes No
1 CHECK PERFORMING OF BASIC DIAGNOSTIC PROCEDURE.  Was the basic diagnostic procedure performed up to STEP 8? Go to step 2  . Perform the basic diagnostic procedure. < Ref. to BASIC DIAGNOSTIC PROCEDURE . >
2 CHECK DTC. 
Check the displayed DTC.		 Are DTCs other than U*** displayed? Perform the diagnosis according to DTC. Go to step 3  .
3 CHECK DTC. 
Check the displayed DTC.		 Is DTC for the bus off or the data no-receive displayed? Perform the diagnosis according to DTC. Go to step 4  .
4 CHECK DTC. 
Check the displayed DTC.		 Is U0420 a current malfunction? Go to step 5  . Go to step 9  .
5 CHECK DTC. 
  1. Turn the ignition switch to OFF.
  2. Disconnect the power steering control module connector.
  3. Connect the disconnected connectors.
  4. Read the DTC using Subaru Select Monitor.
 Is U0420 a current malfunction? Go to step 6  . Go to step 9  .
6 CHECK DTC. 
Using the Subaru Select Monitor, read DTC of all the systems.		 Is the electric power steering data abnormal detected in several modules? Replace the power steering control module. < Ref. to POWER STEERING CONTROL MODULE . > Go to step 7  .
7 REPLACE MODULE. 
  1. Replace the power steering control module.
  2. Read the DTC using Subaru Select Monitor.
 Is U0420 a current malfunction? Go to step 8  . System is normal.
8 CHECK MODULE. 
  1. Reinstall the power steering control module.
  2. Replace the module that the DTC has been detected.
  3. Read the DTC using Subaru Select Monitor.
 Is U0420 a current malfunction? Replace the power steering control module. < Ref. to POWER STEERING CONTROL MODULE . > System is normal.
9 CHECK HARNESS. 
  1. Shake the harness, and check for poor contact.
  2. Using the Subaru Select Monitor, read DTC of CAN system.
 Is U0420 a current malfunction? Repair the poor contact of harness, or replace the harness. Go to step 10  .
10 CHECK CONNECTOR. 
Check the connector used for high speed CAN for poor contact.		 Is there poor contact of connector? Repair the connector that has poor contact, or replace harness. It is possible that temporary poor communication occurs. Delete the DTC.
RENDER: 1.0x

NO RELATED

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Stop DIY work and contact a certified mechanic immediately if any of the following apply:

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