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 C1454: Power Unit Torque Control Inhibit
DTC Detecting condition:
A fault is detected if the torque coordinated control prohibit flag is received from the HEV or electric brake booster.
Trouble symptom:
VDC does not operate.
The warning light turns off when the power module torque down control prohibit flag returns to normal .
- CHECK VDC CONTROL MODULE
.
- Turn READY ON and start the HEV.
- Using the Subaru Select Monitor, read data of [Power Unit Torque Down Control Stop Flag] in the [Data Monitor] of [Brake Control]. Ref. to BRAKE CONTROL (DIAGNOSTICS) (HEV)>DATA MONITOR .
Is the [Power Unit Torque Down Control Stop Flag] set to [ON]?
Yes: Go to 4.
No: Go to 2.
- CHECK WARNING LIGHT
.
Check whether the VDC warning light illuminates after driving for 1 minute or more at a speed of 10 km/h (6 MPH) or more.
Does the VDC warning light illuminate?
Yes: Go to 3.
No: VDC is normal. Clear the memory. Ref. to COMMON (DIAG)>CLEAR MEMORY .
NOTE:DTC may be recorded if cranking is performed during driving .
- CHECK POOR CONTACT OF CONNECTORS
.
Is there poor contact of hybrid vehicle control ECM connector or electric brake booster connector?
Yes: Repair the connector.
No: Go to 4.
- CHECK HYBRID VEHICLE CONTROL ECM DTC
.
Read the DTC of [P-HEV Hybrid Powertrain Control] using the Subaru Select Monitor. Ref. to P-HEV HYBRID POWERTRAIN CONTROL (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) .
Are any DTCs displayed?
Yes: Perform the diagnosis according to the DTC. Ref. to P-HEV HYBRID POWERTRAIN CONTROL (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC)>LIST .
No: Go to 5.
- CHECK ELECTRIC BRAKE BOOSTER DTC
.
Read the DTC of [Electric Brake Booster] using the Subaru Select Monitor. Ref. to ELECTRIC BRAKE BOOSTER (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) .
Are any DTCs displayed?
Yes: Perform the diagnosis according to the DTC. Ref. to ELECTRIC BRAKE BOOSTER (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC)>LIST .
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
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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.