Component Inspection

Ignition switch "OFF".
Ignition switch "ON".
Connect GDS and select "Diagnostic Trouble Codes (DTCs)" mode.
Using a GDS, and clear DTC.
Check if the pressure sensor's service data shows "0 bar" on the GDS while not pressing the brake pedal.
Use the GDS and check that the pressure sensor value rises while pressing the brake pedal.
Is the pressure sensor's data unusually shown?
YES
- Substitute with a known-good HECU and check for proper operation. If problem is corrected, replace HECU and then go to "Verification of Vehicle Repair " procedure.
  NOTE:
  * In a case of replacing HECU, perform following functions
  1. "Steering Angle Sensor Calibration" for steering angle sensor offset correction (refer to C126104 ) -ESP (ESC) only
  2. "Longitudinal Sensor Calibration" for Longitudinal sensor offset correction (refer to C128504 ) - ESP (ESC) only
  3. "Variant Coding" for option coding (refer to C170204 )
NO
- This fault is intermittently caused by pressure sensor. Go to "Verification of Vehicle Repair " procedure.