DSD Information System
Home >> Toyota >> 2021 >> Highlander LE, 4WD >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 37 (Electronically Controlled Brake System (HV) - Diagnostic Codes (08 Of 11)) >> ELECTRONICALLY CONTROLLED BRAKE SYSTEM (for HV Model) >> DTC C1391-00: Abnormal Leak in Accumulator [12/2019 - ] >> Description

DTC C1391-00: Abnormal Leak in Accumulator [12/2019 - ]: Description

WARNING: This page is about a different variant/trim than selected.

This DTC is stored if internal or external brake fluid leaks are detected due to improper sealing in the brake booster with master cylinder assembly or brake booster with accumulator pump assembly. Internal leaks are suspected if the pump motor operates frequently without braking.

DTC No. Detection Item DTC Detection Condition Trouble Area MIL Note
C1391-00 Abnormal Leak in Accumulator Either of the following is detected:
  • When the brake pedal is not depressed and the pump motor is operating, the accumulator pressure sensor value does not increase a certain number of times.
  • When the brake pedal is not depressed and the pump motor is not operating, the accumulator pressure sensor decrease rate exceeds a certain threshold a certain number of times.
  • Brake fluid leaks
  • Brake booster with master cylinder assembly (Malfunctioning internal seal etc.)
  • Brake booster with accumulator pump assembly (Accumulator internal gas pressure decrease, etc.)
Does not come on Output ECU: No. 1 skid control ECU (brake booster with master cylinder assembly)