DTC C1957: LH Actuator Circuit

WARNING: This page is about a different variant/trim than selected.

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 (CROSSTREK MODEL (HEV))>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 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 and H/U and rear brake caliper LH.
3. Measure the resistance between VDCCM and H/U and rear brake caliper LH connector.
  Connector and terminal
  
  (B310) No. 12 - (R154) No. 1:
  
  (B310) No. 13 - (R154) No. 2:
Is the resistance less than 1 Ω?

Yes: Go to 2.

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

Connector and terminal

(R154) No. 1 - Chassis ground:

(R154) No. 2 - Chassis ground:

Is the resistance 1 MΩ or more?

Yes: Go to 3.

No: Repair ground short of harness between VDCCM and H/U and rear brake caliper LH 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 LH connector and chassis ground.
  Connector and terminal
  
  (R154) No. 1 (+) - Chassis ground (-):
  
  (R154) 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 and H/U and rear brake caliper LH connector.
CHECK POOR CONTACT OF CONNECTORS .
Is there poor contact of power supply circuit, ground circuit and VDCCM and H/U connector?

Yes: Repair the connector.

No: Go to 5.
CHECK REAR BRAKE CALIPER .

Turn the ignition switch to OFF.
Disconnect the connectors from rear brake caliper LH.
Measure the resistance between rear brake caliper LH terminals.
Terminals

No. 1 - No. 2:

Is the resistance less than 100 Ω?

Yes: Replace the VDCCM and 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 LH. Ref. to PARKING BRAKE>PARKING BRAKE ACTUATOR .