DTC C057A: Brake Booster Temperature Sensor "B" Circuit High

DTC detecting condition: 

When malfunction of the electric brake booster (internal) temperature sensor is detected.

Trouble symptom: 

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

1. CHECK DATA MONITOR  .

   Using the Subaru Select Monitor, read data of [Motor Drive Circuit Temperature Sensor 1], [Motor Drive Circuit Temperature Sensor 2] in the [Data Monitor] of [Electric Brake Booster]. Ref. to ELECTRIC BRAKE BOOSTER (DIAGNOSTICS)>DATA MONITOR 

   Are the [Motor Drive Circuit Temperature Sensor 1] and [Motor Drive Circuit Temperature Sensor 2] less than -48°C?

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

   No  : Go to  2.

2. CHECK DATA MONITOR  .

   Using the Subaru Select Monitor, read data of [Motor Drive Circuit Temperature Sensor 1], [Motor Drive Circuit Temperature Sensor 2] in the [Data Monitor] of [Electric Brake Booster]. Ref. to ELECTRIC BRAKE BOOSTER (DIAGNOSTICS)>DATA MONITOR 

   Are the [Motor Drive Circuit Temperature Sensor 1] and [Motor Drive Circuit Temperature Sensor 2] 128°C or more?

   Yes  : Go to  3.

   No  : Go to  4.

3. RE-CHECK DATA MONITOR  .
   1. Turn the ignition switch to OFF.
   2. Open the hood and cool the engine compartment for 10 minutes or more.
   3. Using the Subaru Select Monitor, read data of [Motor Drive Circuit Temperature Sensor 1], [Motor Drive Circuit Temperature Sensor 2] in the [Data Monitor] of [Electric Brake Booster]. Ref. to ELECTRIC BRAKE BOOSTER (DIAGNOSTICS)>DATA MONITOR 

   Are the [Motor Drive Circuit Temperature Sensor 1] and [Motor Drive Circuit Temperature Sensor 2] 128°C or more?

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

   No  : Go to  4.

4. RECHECK DTC  .
   1. Using the Subaru Select Monitor, perform the clear memory of [Electric Brake Booster]. Ref. to COMMON (DIAGNOSTICS)>CLEAR MEMORY
   2. Read the DTC of [Electric Brake Booster] using the Subaru Select Monitor. Ref. to ELECTRIC BRAKE BOOSTER (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) 

   Is DTC C057A displayed?

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

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