DTC C1C30: IG1 Circuit Low

DTC detecting condition: 

When malfunction of the IG power supply voltage circuit is detected.

Trouble symptom: 

• The boost function of electric brake booster does not operate.
• The brake boost function by EyeSight does not operate.

Wiring diagram: 

Electric brake booster system Ref. to WIRING SYSTEM>ELECTRIC BRAKE BOOSTER SYSTEM>WIRING DIAGRAM

Courtesy of SUBARU OF AMERICA, INC.

1. CHECK DATA MONITOR OF ELECTRIC BRAKE BOOSTER CONTROL MODULE  .

   Using the Subaru Select Monitor, read data of [IGN Power Supply Signal] in the [Data monitor] of [Electric Brake Booster]. Ref. to ELECTRIC BRAKE BOOSTER (DIAGNOSTICS)>DATA MONITOR 

   After the ignition switch is turned to ON, does the [IGN Power Supply Signal] turn to [ON]?

   Yes  : Go to  2.

   No  : Go to  3.

2. CHECK DATA MONITOR OF VDC CONTROL MODULE  .

   Using the Subaru Select Monitor, read data of [Ignition Signal] in the [Data monitor] of [Brake Control]. Ref. to BRAKE CONTROL (DIAGNOSTICS)>DATA MONITOR

   After the ignition switch is turned to ON, does the [Ignition Signal] turn to [ON]?

   Yes  : Go to  3.

   No  : Perform the diagnosis for VDC. Ref. to BRAKE CONTROL (DIAGNOSTICS)>BASIC DIAGNOSTIC PROCEDURE

3. CHECK ELECTRIC BRAKE BOOSTER CONTROL MODULE CONNECTOR  .
   1. Turn the ignition switch to OFF.
   2. Check the connecting condition of the electric brake booster control module connector and poor contact of terminal.

   Is there looseness, deformation, or corrosion at the connectors?

   Yes  : Repair or replace the connector.

   No  : Go to  4.

4. CHECK POWER SUPPLY CIRCUIT. (CHECK IGNITION POWER SUPPLY CIRCUIT.)  .
   1. Turn the ignition switch to ON.
   2. Measure the voltage between electric brake booster control module connector and chassis ground.

      Connector & terminal 

      (B80) No. 20 (+) - Chassis ground (-):

   Is the voltage 10 - 16 V?

   Yes  : Go to  5.

   No  : Repair or replace the harness.

5. RECHECK DTC  .
   1. Connect the electric brake booster control module connector.
   2. Using the Subaru Select Monitor, perform the clear memory of [Electric Brake Booster]. Ref. to COMMON (DIAGNOSTICS)>CLEAR MEMORY
   3. Read the DTC of [Electric Brake Booster] using the Subaru Select Monitor. Ref. to ELECTRIC BRAKE BOOSTER (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) 

   Is DTC C1C30 displayed?

   Yes  : Replace the electric brake booster control module. Ref. to BRAKE>BRAKE BOOSTER

   No  : Currently, it is normal. Finish the diagnosis.