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 C1921 Parking Position Switch Circuit: Wiring Diagram
Parking brake/brake fluid level warning light system < Ref. to appropriate wiring diagram in SYSTEM WIRING DIAGRAM article. >
| Step | Check | Yes | No |
|---|---|---|---|
| 1 CHECK OPERATION OF ELECTRONIC PARKING BRAKE. Operate the parking brake switch. |
Does the electronic parking brake operate properly? | Ask the customer whether the switch operation was performed normally. If it was normal, temporary poor contact is the cause. | Go to step 2 . |
2 CHECK HARNESS (CHECK FOR OPEN CIRCUIT).
|
Is the resistance less than 1 Ω? | Go to step 3 . | Repair harness and connector between VDCCM & H/U and parking brake switch connector. |
| 3 CHECK HARNESS (CHECK FOR GROUND SHORT CIRCUIT). Measure the resistance between the parking brake switch connector and chassis ground. Connector & terminal (i163) No. 2 - Chassis ground: (i163) No. 1 - Chassis ground: (i163) No. 5 - Chassis ground: (i163) No. 6 - Chassis ground: |
Is the resistance 1 MΩ or more? | Go to step 4 . | Repair ground short of harness between VDCCM & H/U and parking brake switch connector. |
4 CHECK HARNESS (CHECK FOR SHORT CIRCUIT TO POWER SUPPLY).
|
Is the voltage less than 1 V? | Go to step 5 . | Repair short to power supply of harness between VDCCM & H/U and parking brake switch connector. |
| 5 CHECK PARKING BRAKE SWITCH. Check the parking brake switch. < Ref. to INSPECTION , Parking Brake Switch. > |
Is the parking brake switch normal? | Go to step 6 . | Replace the parking brake switch. < Ref. to PARKING BRAKE SWITCH . > |
6 CHECK VDCCM & H/U.
|
Is the same DTC displayed? | Replace the VDCCM & H/U. < Ref. to VDC CONTROL MODULE AND HYDRAULIC CONTROL UNIT (VDCCM & H/U) . > | Go to step 7 . |
| 7 CHECK DETECTION OF OTHER DTCS FOR VDC. < Ref. to READ DIAGNOSTIC TROUBLE CODE (DTC) . > |
Is any other DTC displayed? | Perform the diagnosis according to DTC. < Ref. to LIST OF DIAGNOSTIC TROUBLE CODE (DTC) . > | Currently, it is normal. There may have been a poor contact in the harness and connector or a temporarily 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.