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.
Model With Eyesight (IMPREZA Model) • CVT Model (CROSSTREK Model)
DTC detecting condition:
- A fault is detected if a change of the vehicle speed from high to low occurs for a predetermined number of times or more, while a change of the stop light switch from OFF to ON is not detected.
- A fault is detected if stop light switch ON status continues for long time while the vehicle speed is at the predetermined speed or higher.
Trouble symptom:
- VDC does not operate.
- Hill start assist does not operate.
- EyeSight does not operate. (Models with EyeSight)
Wiring diagram:
Vehicle dynamics control system Ref. to WIRING SYSTEM (IMPREZA MODEL)>VEHICLE DYNAMICS CONTROL SYSTEM . Ref. to WIRING SYSTEM (CROSSTREK MODEL (EXCEPT FOR HEV))>VEHICLE DYNAMICS CONTROL SYSTEM .
Before performing diagnosis, refer to "CAUTION" in "General Description". Ref. to BRAKE CONTROL (DIAGNOSTICS)>GENERAL DESCRIPTION>CAUTION .
- INTERVIEW CUSTOMERS
.
Make sure that the operation was performed in which accelerator pedal and brake pedal were depressed simultaneously (with depressing brake pedal with left foot).
Were the acceleration pedal and brake pedal depressed simultaneously?
Yes: System is normal. (DTC may be recorded if the brake pedal is always depressed while driving.)
No: Go to 2.
- CHECK STOP LIGHT RELAY
.
- Turn the ignition switch to OFF.
- Measure the resistance of stop light relay terminals.
Terminals
No. 8 - No. 9:
Is the resistance less than 1 Ω?
Yes: Replace the stop light relay. Ref. to VEHICLE DYNAMICS CONTROL (VDC)>RELAY AND FUSE .
No: Go to 3.
- CHECK VDCCM AND H/U CONNECTOR
.
Disconnect the connector from the VDCCM and H/U.
Is there poor contact or damage of the VDCCM and H/U connector?
Yes: Repair the VDCCM and H/U connector.
No: Go to 4.
- CHECK STOP LIGHT SWITCH CIRCUIT
.
- Turn the ignition switch to ON.
- Measure the voltage between stop light relay and chassis ground.
Connector and terminal
(B225) No. 9 (+) - Chassis ground (-):
Is the voltage 10 V or more when the stop light switch is OFF (when pedal is not depressed)?
Yes: Repair the stop light switch circuit.
No: Go to 5.
- 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)>INSPECTION MODE .
- 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 and H/U. Ref. to VEHICLE DYNAMICS CONTROL (VDC)>VDC CONTROL MODULE AND HYDRAULIC CONTROL UNIT (VDCCM AND H/U) .
No: Go to 6.
- 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.
NO RELATED
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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.