DTC C1B0E Solenoid Valve Main Relay Circuit Low: Notes

1. - 

DTC detecting condition: 

• DTC C1B0E

  When the vehicle's state is READY ON: When IG1 terminal voltage is 9.5 V or more and the main relay is commanded ON, the relay contact is in OFF state (BS terminal voltage is less than 3.5 V), and this condition continues for 0.05 seconds or more.

  When the vehicle's state is READY OFF: When the main relay is commanded ON, the relay contact is in OFF state (BS terminal voltage is less than 3.5 V), and this condition continues for 0.05 seconds or more.

• DTC C1B0F

  When the main relay is commanded OFF by the ECM, the relay contact is in ON state (BS terminal voltage is 3.5 V or more), and this condition continues for 4.5 seconds or more.

Trouble symptom: 

• Regenerative brake cannot be controlled.
• Brake assist does not operate.
• EyeSight functions (ACC/PCS) do not operate.

Wiring diagram: 

Electronic controlled brake system Ref. to WIRING SYSTEM (CROSSTREK MODEL (HEV))>ELECTRIC CONTROL BRAKE SYSTEM .

Courtesy of SUBARU OF AMERICA, INC.

1. CHECK CONNECTOR  .

   Check the connecting condition of the EBB control module connector.

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

   Yes:  Repair or replace the connector.

   No:  Go to  2.

2. CHECK EBB CONTROL MODULE  .
   1. Turn the ignition switch to OFF.
   2. Disconnect the EBB control module connector.
   3. Measure the voltage between EBB control module connector and chassis ground.

      Connector & terminal 

      (AD82) No. 10 (+) - Chassis ground (-):

   Is the voltage 11 - 14 V?

   Yes:  Go to  3.

   No:  Repair or replace the harness.

3. CHECK DTC  .
   1. Connect the EBB control module connector.
   2. Using the Subaru Select Monitor, perform the clear memory of [Electric Brake Booster]. Ref. to COMMON (DIAG)>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) .

   Are DTCs C1B0E and C1B0F displayed?

   Yes:  Replace the brake booster assembly (with the master cylinder). Ref. to BRAKE>BRAKE BOOSTER .

   No:  Currently, it is normal. There may have been a temporary poor contact in the harness and connector or a temporary noise interference.