Subaru Crosstrek Service Manual: Dtc u0122 lost communication with vehicle dynamics control module

DTC DETECTING CONDITION:

No data from VDCCM is received.

TROUBLE SYMPTOM:

ABS warning light and VDC warning light illuminate.

1.CHECK PERFORMING OF BASIC DIAGNOSTIC PROCEDURE.

Was the basic diagnostic procedure performed up to STEP 3?

Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC U0122 LOST COMMUNICATION WITH VEHICLE DYNAMICS CONTROL MODULE">Go to Step 2.

Perform the basic diagnostic procedure. Basic Diagnostic Procedure">

2.CHECK DTC.

Check the displayed DTC.

Are DTCs other than U*** displayed?

Perform the diagnosis according to DTC.

Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC U0122 LOST COMMUNICATION WITH VEHICLE DYNAMICS CONTROL MODULE">Go to Step 3.

3.CHECK DTC.

Check the displayed DTC.

Is U0122 a current malfunction?

Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC U0122 LOST COMMUNICATION WITH VEHICLE DYNAMICS CONTROL MODULE">Go to Step 4.

Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC U0122 LOST COMMUNICATION WITH VEHICLE DYNAMICS CONTROL MODULE">Go to Step 8.

4.CHECK DTC.

1) Check CAN communication circuit. CAN Communication Circuit Check">

2) Read the DTC using Subaru Select Monitor. Read Diagnostic Trouble Code (DTC)">

Is U0122 a current malfunction?

Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC U0122 LOST COMMUNICATION WITH VEHICLE DYNAMICS CONTROL MODULE">Go to Step 5.

Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC U0122 LOST COMMUNICATION WITH VEHICLE DYNAMICS CONTROL MODULE">Go to Step 8.

5.CHECK DTC.

Using the Subaru Select Monitor, read DTC of all the systems. Read Diagnostic Trouble Code (DTC)">

Is the VDC data no-receive detected in several modules?

Replace the VDC CM. VDC Control Module and Hydraulic Control Unit (VDCCM&H/U)">

Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC U0122 LOST COMMUNICATION WITH VEHICLE DYNAMICS CONTROL MODULE">Go to Step 6.

6.REPLACE MODULE.

1) Replace the VDC CM.

2) Read the DTC using Subaru Select Monitor. Read Diagnostic Trouble Code (DTC)">

Is U0122 a current malfunction?

Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC U0122 LOST COMMUNICATION WITH VEHICLE DYNAMICS CONTROL MODULE">Go to Step 7.

System is normal.

7.CHECK MODULE.

1) Reinstall the VDC CM.

2) Replace the module that the DTC has been detected.

3) Read the DTC using Subaru Select Monitor. Read Diagnostic Trouble Code (DTC)">

Is U0122 a current malfunction?

Replace the VDC CM. VDC Control Module and Hydraulic Control Unit (VDCCM&H/U)">

System is normal.

8.CHECK HARNESS.

1) Shake the harness, and check for poor contact.

2) Read the DTC using Subaru Select Monitor. Read Diagnostic Trouble Code (DTC)">

Is U0122 a current malfunction?

Repair the poor contact of harness, or replace the harness.

Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC U0122 LOST COMMUNICATION WITH VEHICLE DYNAMICS CONTROL MODULE">Go to Step 9.

9.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.

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