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 C1984: Brake Maintenance Mode
DTC Detecting condition:
This malfunction is stored when the brake maintenance mode is in progress.
Trouble symptom:
Parking brake system does not operate.
If any other DTC is detected, start the diagnosis beginning from that DTC .
- CHECK ELECTRONIC PARKING MODE
.
Is the brake maintenance mode in progress?
Yes: Currently, it is normal. Although DTC C1984 is input during the brake maintenance mode, it is normal. Ref. to PARKING BRAKE>PARKING BRAKE SYSTEM>OPERATION>BRAKE MAINTENANCE MODE .
No: Go to 2.
- CHECK OPERATION OF ELECTRONIC PARKING BRAKE
.
- Using the Subaru Select Monitor, perform the clear memory of [Brake Control]. Ref. to COMMON (DIAG)>CLEAR MEMORY .
- Apply the electronic parking brake several times.
- Read the DTC of [Brake Control] using the Subaru Select Monitor. Ref. to BRAKE CONTROL (DIAGNOSTICS) (HEV)>DIAGNOSTIC TROUBLE CODE (DTC) .
Is DTC stored regardless of whether the electronic parking brake operates or does not operate?
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 3.
- 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 .
Perform the diagnosis from step 1 again, and if the same DTC is stored, replace the VDCCM and H/U. Ref. to VEHICLE DYNAMICS CONTROL (VDC)>VDC CONTROL MODULE AND HYDRAULIC CONTROL UNIT (VDCCM & H/U) .
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.