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 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 VDC Control Module & H/U and rear brake caliper LH.
3. Measure the resistance between VDC Control Module & H/U and rear brake caliper LH connector.
  Connector & 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 VDC Control Module & 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 & 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 VDC Control Module & 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 & 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 VDC Control Module & H/U and rear brake caliper LH connector.
CHECK POOR CONTACT OF CONNECTORS .
Is there poor contact of power supply circuit, ground circuit and VDC Control Module & 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 LH.
3. Measure the resistance between rear brake caliper LH terminals.
  Terminals
  
  No. 1 - No. 2:
  
  Is the resistance less than 100 Ω?
  
  Yes : Replace the VDC Control Module & 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 .