DTC Advanced Diagnostics: C1120-14
DTC C1120-14: Electric Parking Brake Switch Circuit Malfunction
NOTE
Initial Diagnosis:
The initial on-board diagnosis occurs right after the vehicle condition is turned to the ON mode, and the ABS/VSA indicator comes on, and continues until the indicator goes off.
Regular Diagnosis:
The regular on-board diagnosis begins right after the ABS/VSA indicator goes off, and it continues until the vehicle condition is turned to the OFF (LOCK) mode.
Review "How to troubleshoot the VSA system" before doing the DTC troubleshooting procedure.
Test-drive the vehicle according to local traffic conditions and regulations. Do not test-drive on a lift unless specified.
The possible causes shown may not be a complete list of all potential problems, and it is possible that there may be other causes.

Confirmation Procedure
Basic Condition:
12 volt battery voltage 9.6 - 16.5 V

With the Driving Pattern:
1.
Turn the vehicle to the ON mode.
Execution
Regular Diagnosis
Duration
–
DTC Type
1 drive cycle
Brake system indicator (red) blink
Brake system indicator (amber) on
Fail Safe Action
Stop manual operating function
Stop emergency brake function
Possible Cause
Open, Short to ground, or Poor connection between the electric parking brake/automatic brake hold switch and the VSA modulator-control unit (SW1, SW3, SW4, SW6 lines)
Electric parking brake/automatic brake hold switch failure
VSA modulator-control unit internal failure