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Home >> Toyota >> 2021 >> Highlander LE, 4WD >> Repair and Diagnosis >> Electrical >> Starter >> Stop And Start System - Diagnostic Codes (1 Of 3) >> Stop And Start System >> DTC P0555-00: Brake Booster Pressure Sensor (running); DTC P0555-2A: Brake Booster Pressure Sensor Signal Stuck In Range [12/2019 - 10/2022] >> Description

DTC P0555-00: Brake Booster Pressure Sensor (running); DTC P0555-2A: Brake Booster Pressure Sensor Signal Stuck In Range [12/2019 - 10/2022]: Description

The engine stop and start ECU determines changes in the brake booster assembly pressure based on the voltage signal received from the vacuum sensor assembly in the brake booster assembly.

If the output value of the vacuum sensor assembly remains the same even though the brake booster assembly pressure changes when the brake pedal is operated or the vehicle is being driven, the engine stop and start ECU judges that the sensor is stuck.

When sticking of the sensor is detected, the engine stop and start ECU stores DTC P0555-00 or P0555-2A and blinks the stop and start cancel indicator.

DTC No. Detection Item DTC Detection Condition Trouble Area Warning Indicate Memory Note
P0555-00 Brake Booster Pressure Sensor (running) The change in vacuum while stopping the vehicle 30 times from a speed of 30 km/h (19 mph) or more was 0.3 kPa (2 mmHg, 0.09 in.Hg) or less (1 trip detection logic).
  • Vacuum sensor assembly
  • Brake booster assembly
  • Vacuum hose (brake booster hose)
  • Engine stop and start ECU
Blinks DTC stored SAE Code: P0556
P0555-2A Brake Booster Pressure Sensor Signal Stuck In Range The change in vacuum is 0.3 kPa (2 mmHg, 0.09 in.Hg) or less more than 3 times when the brake pedal is firmly depressed to stop the vehicle (deceleration of 0.15 G or more for 1 second or more) (1 trip detection logic).
  • Vacuum sensor assembly
  • Brake booster assembly
  • Vacuum hose (brake booster hose)
  • Engine stop and start ECU
Blinks DTC stored SAE Code: P0556