DTC Troubleshooting: C1120-14
DTC C1120-14: Electric Parking Brake Switch Circuit Malfunction
NOTE: Before you troubleshoot, review the general troubleshooting information.

DTC Description
DTC
C1120-14 Electric Parking Brake Switch Circuit Malfunction
  

1.
Problem verification:

Problem verification
?1.
Turn the vehicle to the ON mode.

?2.
Clear the DTC with the HDS.


?3.
Turn the vehicle to the OFF (LOCK) mode, then to the ON mode.

?4.
Check the parameter(s) below with the HDS.
Signal
Current conditions
Values
Unit
Electric Parking Brake Switch Status
    

Is there INVALID indicated?

     
YES
     
     
     
The failure is duplicated. Go to step 2.
     
NO
     
     
     
Intermittent failure, the system is OK at this time. Refer to intermittent failures troubleshooting.?
2.
Electric parking brake switch check:

Electric parking brake switch check
?1.
Turn the vehicle to the OFF (LOCK) mode.

?2.
Check the electric parking brake switch.

Is the electric parking brake switch OK?

     
YES
     
     
     
Go to step 3.
     
NO
     
     
     
3.
Shorted wire check (SW1, SW3, SW4, SW6 lines):

Shorted wire check (SW1, SW3, SW4, SW6 lines)
?1.
Disconnect the following connectors.
Electric parking brake switch 12P connector
VSA modulator-control unit 46P connector

?2.
Check for continuity between the following test points and body ground individually.
Test condition
Vehicle OFF (LOCK) mode
 
Electric parking brake switch 12P connector: disconnected
 
VSA modulator-control unit 46P connector: disconnected

Connector
Test circuit
Terminal
VSA modulator-control unit 46P connector
SW1
No. 26
SW3
No. 27
SW4
No. 28
SW6
No. 29

Is there continuity?

     
YES
     
     
     
Repair a short to body ground in the wires between the VSA modulator-control unit and the electric parking brake switch.?
     
NO
     
     
     
The SW1, SW3, SW4, SW6 wires are not shorted. Go to step 4.
4.
Open wire check (SW1, SW3, SW4, SW6 lines):

Open wire check (SW1, SW3, SW4, SW6 lines)
?1.
Check for continuity between test points 1 and 2.
Test condition
Vehicle OFF (LOCK) mode
 
Electric parking brake switch 12P connector: disconnected
 
VSA modulator-control unit 46P connector: disconnected
Test point 1
Electric parking brake switch 12P connector (female terminals) No. 2:
Test point 2
VSA modulator-control unit 46P connector No. 26

Test point 1
Electric parking brake switch 12P connector (female terminals) No. 1:
Test point 2
VSA modulator-control unit 46P connector No. 27

Test point 1
Electric parking brake switch 12P connector (female terminals) No. 9:
Test point 2
VSA modulator-control unit 46P connector No. 28

Test point 1
Electric parking brake switch 12P connector (female terminals) No. 10:
Test point 2
VSA modulator-control unit 46P connector No. 29


Is there continuity?

     
YES
     
     
     
Check for loose terminals and poor connections in the VSA modulator-control unit 46P connector. Check for any authorized service information related to the DTCs or symptoms you are troubleshooting. If they are OK, replace the VSA modulator-control unit.?
     
NO
     
     
     
Repair an open in the wires between the VSA modulator-control unit and the electric parking brake switch.?