DTC C1951: Actuator

DTC detecting condition: 

A fault is detected if the electronic parking brake operation status does not match the operation request.

Trouble symptom: 

Parking brake system does not operate.

Failure detection pattern: 

• "Primary" (high-priority diagnosis)

Warning light/indicator light: 

The combination of DTC and warning light display may differ from the list depending on vehicle conditions and driving conditions at the time of failure detection.

• ABS warning light -
• VDC warning light & VDC operation indicator light -
• Electronic parking brake warning light (red)◦
• Brake warning light (EBD warning light) (red) -

Wiring diagram: 

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

Courtesy of SUBARU OF AMERICA, INC.

1. CHECK BATTERY  .
   1. Turn the ignition switch to OFF.
   2. Check the battery voltage. Ref. to STARTING/CHARGING SYSTEMS (H4DO)>BATTERY>INSPECTION .

   Is the voltage 10 - 15 V?

   Yes:  GO TO  2.

   No:  Charge or replace the battery. Ref. to STARTING/CHARGING SYSTEMS (H4DO)>BATTERY . Check the generator circuit.

2. CHECK VDCCM & H/U GROUND CIRCUIT (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 connector and chassis ground.

      Connector & terminal 

      (B66) No. 46 - Chassis ground:

   Is the resistance less than 10 Ω?

   Yes:  GO TO  3.

   No:  Repair the VDCCM & H/U ground circuit.

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

      Connector & terminal 

      (B66) No. 2 - (L141) No. 2:

      (B66) No. 3 - (L141) No. 1:

      (B66) No. 13 - (L142) No. 2:

      (B66) No. 12 - (L142) No. 1:

   Is the resistance less than 1 Ω?

   Yes:  GO TO  4.

   No:  Repair harness and connector between VDCCM & H/U and rear brake caliper connector.

4. CHECK POOR CONTACT OF CONNECTORS  .

   Is there poor contact of power supply circuit, ground circuit and VDCCM & H/U connector?

   Yes:  Repair the connector.

   No:  GO TO  5.

5. CHECK DRIVER'S DOOR SWITCH  .

   Check the driver's door switch. Ref. to SECURITY AND LOCKS>DOOR LOCK CONTROL SYSTEM>INSPECTION>CHECK DOOR SWITCH .

   Is the driver's door switch normal?

   Yes:  GO TO  6.

   No:  Repair the driver's door switch or circuit.

6. CHECK VDCCM & H/U  .
   1. Connect all connectors.
   2. Using the Subaru Select Monitor, perform the clear memory of [Brake Control]. Ref. to COMMON (DIAGNOSTICS)>CLEAR MEMORY .
   3. Read the DTC of [Brake Control] using the 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 of [Brake Control] using the Subaru Select Monitor. Ref. to BRAKE CONTROL (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) .

   Is any other DTC displayed?

   Yes:  Perform the diagnosis according to the 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.