DTC C1923: Auto Vehicle Hold Switch Circuit

DTC detecting condition: 

A fault is detected if the AVH switch is pressed and held for a long period of time.

Trouble symptom: 

AVH function cannot be set.

Wiring diagram: 

Parking brake/brake fluid level warning light system Ref. to WIRING SYSTEM>PARKING BRAKE/BRAKE FLUID LEVEL WARNING LIGHT SYSTEM .

Courtesy of SUBARU OF AMERICA, INC.

1. CHECK POWER SUPPLY OF AVH SWITCH. 
   1. Turn the ignition switch to OFF.
   2. Disconnect the connector from the AVH switch.
   3. Turn the ignition switch to ON.
   4. Measure the voltage between the AVH switch connector and chassis ground.

      Connector and terminal 

      (i334) No. 1 (+) - Chassis ground (-):

   Is the voltage 10 - 15 V?

   Yes  : Go to  2.

   No  : Repair the power supply circuit of AVH switch.

2. CHECK HARNESS (CHECK FOR OPEN CIRCUIT). 
   1. Turn the ignition switch to OFF.
   2. Disconnect the connector from the VDCCM & H/U.
   3. Measure the resistance between VDCCM & H/U and AVH switch connector.

      Connector and terminal 

      (i334) No. 4 - (B310) No. 33:

   Is the resistance less than 1 Ω?

   Yes  : Go to  3.

   No  : Repair harness and connector between VDCCM & H/U and AVH switch connector.

3. CHECK HARNESS (CHECK FOR GROUND SHORT CIRCUIT). 

   Measure the resistance between AVH switch connector and chassis ground.

   Connector and terminal 

   (i334) No. 4 - Chassis ground:

   Is the resistance 1 MΩ or more?

   Yes  : Go to  4.

   No  : Repair ground short of harness between VDCCM & H/U and AVH switch connector.

4. CHECK HARNESS (CHECK FOR SHORT CIRCUIT TO POWER SUPPLY). 
   1. Turn the ignition switch to ON.
   2. Measure the voltage between the AVH switch connector and chassis ground.

      Connector and terminal 

      (i334) No. 4 (+) - Chassis ground (-):

   Is the voltage less than 1 V?

   Yes  : Go to  5.

   No  : Repair short to power supply of harness between VDCCM & H/U and AVH switch connector.

5. CHECK AVH SWITCH. 

   Check the AVH switch. Ref. to VEHICLE DYNAMICS CONTROL (VDC)>AUTO VEHICLE HOLD SWITCH>INSPECTION .

   Is the check result OK?

   Yes  : Go to  6.

   No  : Replace the AVH switch. Ref. to VEHICLE DYNAMICS CONTROL (VDC)>AUTO VEHICLE HOLD SWITCH .

6. CHECK VDCCM & H/U. 
   1. Connect all connectors.
   2. Using the Subaru Select Monitor, perform the clear memory. Ref. to COMMON (diag)>CLEAR MEMORY .
   3. Execute the inspection mode. Ref. to BRAKE CONTROL (DIAGNOSTICS)>INSPECTION MODE .
   4. Read the DTC using Subaru Select Monitor. Ref. to BRAKE CONTROL (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) .

   Is the same DTC displayed?

   Yes  : Replace the VDCCM & H/U. Ref. to VEHICLE DYNAMICS CONTROL (VDC)>VDC CONTROL MODULE AND HYDRAULIC CONTROL UNIT (VDCCM & H/U) .

   No  : Go to  7.

7. CHECK DETECTION OF OTHER DTCS FOR VDC. 

   Read the DTC using Subaru Select Monitor. Ref. to BRAKE CONTROL (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) .

   Is any other DTC displayed?

   Yes  : Perform the diagnosis according to DTC. Ref. to BRAKE CONTROL (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC)>LIST .

   No  : Currently, it is normal. There may have been a temporary poor contact in the harness and connector or a temporary noise interference.