DTC C1956 :RH Actuator Circuit

DTC detecting condition:

A fault is detected, if the motor control mismatch occurs during the motor operation.
A fault is detected if the motor circuit or harness is open or shorted.

Trouble symptom:

Parking brake system does not operate.

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.

NOTE: This DTC may be stored when the rear brake caliper connector is disconnected regardless of the ignition switch condition (ON/OFF). Perform the Clear Memory Mode after diagnosis if a DTC is recorded. Ref. to COMMON (diag)>CLEAR MEMORY .

CHECK HARNESS (CHECK FOR OPEN CIRCUIT).
1. Turn the ignition switch to OFF.
2. Disconnect the connectors from the VDCCM & H/U and rear brake caliper RH.
3. Measure the resistance between VDCCM & H/U and rear brake caliper RH connector.
  Connector and terminal
  
  (B310) No. 2 - (R153) No. 2:
  
  (B310) No. 3 - (R153) No. 1:
Is the resistance less than 1 Ω?

Yes : Go to 2.

No : Repair harness and connector between VDCCM & H/U and rear brake caliper RH connector.
CHECK HARNESS (CHECK FOR GROUND SHORT CIRCUIT).
Measure the resistance between the rear brake caliper RH connector and chassis ground.

Connector and terminal

(R153) No. 1 - Chassis ground:

(R153) No. 2 - Chassis ground:

Is the resistance 1 MΩ or more?

Yes : Go to 3.

No : Repair ground short of harness between VDCCM & H/U and rear brake caliper RH connector.
CHECK HARNESS (CHECK FOR SHORT CIRCUIT TO POWER SUPPLY).
1. Turn the ignition switch to ON.
2. Measure the voltage between the rear brake caliper RH connector and chassis ground.
  Connector and terminal
  
  (R153) No. 1 (+) - Chassis ground (-):
  
  (R153) No. 2 (+) - Chassis ground (-):
Is the voltage less than 1 V?

Yes : Go to 4.

No : Repair short to power supply of harness between VDCCM & H/U and rear brake caliper RH connector.
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.
CHECK REAR BRAKE CALIPER.
1. Turn the ignition switch to OFF.
2. Disconnect the connectors from rear brake caliper RH.
3. Measure the resistance between rear brake caliper RH terminals.
  Terminals
  
  No. 1 - No. 2:
Is the resistance less than 100 Ω?

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

No : Replace the parking brake actuator assembly RH. Ref. to KING BRAKE ACTUATOR .