Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
DTC C1935: Ignition Switch Circuit
DTC Detecting condition:
A fault is detected after a predetermined period of time, if the hardware IGN signal and CAN IGN signal were compared and did not match.
Trouble symptom:
Electronic parking brake warning light illuminates.
Wiring diagram:
Vehicle dynamics control system Ref. to WIRING SYSTEM (CROSSTREK MODEL (HEV))>VEHICLE DYNAMICS CONTROL SYSTEM .
- CHECK VDCCM AND H/U INPUT VOLTAGE
.
- Turn the ignition switch to OFF.
- Disconnect the connector from the VDCCM and H/U.
- Turn the ignition switch to ON.
- Measure the voltage between VDCCM and H/U connector and chassis ground.
Connector and terminal
(B310) No. 35 (+) - Chassis ground (-):
Is the voltage 10 - 15 V?
Yes: Go to 2.
No: Repair or replace the open circuit in the power supply circuit including the fuse.
- CHECK VDCCM AND H/U GROUND CIRCUIT (CHECK FOR OPEN CIRCUIT)
.
- Turn the ignition switch to OFF.
- Measure the resistance between VDCCM and H/U connector and chassis ground.
Connector and terminal
(B310) No. 14 - Chassis ground:
Is the resistance less than 10 Ω?
Yes: Go to 3.
No: Repair the VDCCM and H/U ground circuit.
- CHECK INPUT VOLTAGE OF BODY INTEGRATED UNIT
.
Using the Subaru Select Monitor, read data of [IGN voltage] in the [Data Monitor] of [Body Control]. Ref. to BODY CONTROL (DIAGNOSTICS)>DATA MONITOR .
Is [IGN voltage] 10 - 15 V?
Yes: Go to 4.
No: Perform the diagnosis for the body control system. Ref. to BODY CONTROL (DIAGNOSTICS)>BASIC DIAGNOSTIC PROCEDURE .
- CHECK LAN SYSTEM
.
Read the DTC of the LAN system using the Subaru Select Monitor. Ref. to LAN SYSTEM (DIAGNOSTICS) (HEV)>DIAGNOSTIC TROUBLE CODE (DTC) .
Is DTC for LAN system displayed?
Yes: Perform the diagnosis according to the DTC. Ref. to LAN SYSTEM (DIAGNOSTICS) (HEV)>DIAGNOSTIC TROUBLE CODE (DTC)>LIST .
No: Go to 5.
- 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 6.
- CHECK VDCCM AND H/U
.
- Connect all connectors.
- Using the Subaru Select Monitor, perform the clear memory of [Brake Control]. Ref. to COMMON (DIAG)>CLEAR MEMORY .
- Execute the inspection mode. Ref. to BRAKE CONTROL (DIAGNOSTICS) (HEV)>INSPECTION MODE .
- Read the DTC of [Brake Control] using the Subaru Select Monitor. Ref. to BRAKE CONTROL (DIAGNOSTICS) (HEV)>DIAGNOSTIC TROUBLE CODE (DTC) .
Is the same DTC displayed?
Yes: Replace the VDCCM and H/U. Ref. to VEHICLE DYNAMICS CONTROL (VDC)>VDC CONTROL MODULE AND HYDRAULIC CONTROL UNIT (VDCCM & H/U) .
No: Go to 7.
- CHECK DETECTION OF OTHER DTCS FOR VDC
.
Read the DTC of [Brake Control] using the Subaru Select Monitor. Ref. to BRAKE CONTROL (DIAGNOSTICS) (HEV)>DIAGNOSTIC TROUBLE CODE (DTC) .
Is any other DTC displayed?
Yes: Perform the diagnosis according to the DTC. Ref. to BRAKE CONTROL (DIAGNOSTICS) (HEV)>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.
NO RELATED
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Affiliate disclosure: We may earn a commission at no extra cost to you.
When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.