DTC C05A1-28: Brake Pressure Sensor "E" Signal Bias Level Out of Range / Zero Adjustment Failure [11/2020 - ]: Procedure

1. Check that the brake pedal and the brake pedal stroke sensor assembly are properly installed and that the pedal can be depressed normally.
2. Check and adjust the brake pedal height.

   HINT: 

   Refer to ADJUSTMENT [11/2020 - 12/2023] , or refer to ADJUSTMENT [12/2023 - ]

3. Adjust the brake pedal stroke sensor assembly.

   HINT: 

   Refer to INSTALLATION [11/2020 - 12/2022] , or refer to INSTALLATION [12/2022 - ]

   Result

   Proceed to
   NEXT

Result: 

NEXT 

See step  2

1. Check that the servo pressure sensor output value is within 0.00 to 1.53 MPa when the brake pedal not depressed.

   Chassis > Brake Booster > Data List 

   Tester Display	Measurement Item	Range	Normal Condition	Diagnostic Note
   Servo Pressure	Pressure value of servo	Min.: 0.00 MPa Max.: 24.48 MPa	Brake pedal released: 0.00 to 1.53 MPa	Brake pedal is being depressed: Changes in proportion to the depression force of the brake pedal

   Chassis > Brake Booster > Data List 

   Tester Display
   Servo Pressure

   HINT: 

   If the servo pressure sensor output value is within 0.00 to 1.53 MPa, the No. 1 skid control ECU (brake booster with master cylinder assembly) automatically performs zero point calibration every time the ignition switch is turned to ON.

   Therefore, if the servo pressure sensor output value is not within 0.00 to 1.53 MPa, replace the No. 1 skid control ECU (brake booster with master cylinder assembly) with a new one.

   Result

   Result	Proceed to
   The value of Servo Pressure is between 0.00 and 1.53 MPa	A
   None of the above conditions are met	B

Result: 

B 

REPLACE BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY. Refer to  REMOVAL [11/2020 - 11/2021]  , or refer to  REMOVAL [11/2021 - 12/2022]  , or refer to  REMOVAL [12/2022 - 12/2023]  , or refer to  REMOVAL [12/2023 - ] 

Result: 

A 

See step  3

Pre-procedure1

• None

• Clear the DTCs.

  Chassis > Brake Booster > Clear DTCs 

  Result

  Proceed to
  NEXT

Post-procedure1

• Turn the ignition switch off.

Result: 

NEXT 

See step  4

Pre-procedure1

• Based on the Freeze Frame Data and interview with the customer, attempt to reproduce the conditions when the malfunction occurred.

• Check if the same DTC is output.

  Chassis > Brake Booster > Trouble Codes 

  HINT: 

  Even if the DTC is cleared, it will immediately be output again if the servo pressure sensor zero point malfunction remains.

  Result

  Result	Proceed to
  C05A1-28 is not output	A
  C05A1-28 is output	B

Post-procedure1

• None

Result: 

A 

USE SIMULATION METHOD TO CHECK. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [11/2020 - ] 

Result: 

B 

REPLACE BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY. Refer to  REMOVAL [11/2020 - 11/2021]  , or refer to  REMOVAL [11/2021 - 12/2022]  , or refer to  REMOVAL [12/2022 - 12/2023]  , or refer to  REMOVAL [12/2023 - ]