HYDRAULIC BRAKE BOOSTER (HBB) DIAGNOSIS
TSB Revision
BASIC BRAKE SYSTEM
35A-77
STEP 8. Recheck for diagnostic trouble code.
(1) Erase the DTC memory.
(2) Recheck for diagnostic trouble code.
Q: Is DTC 56 set?
YES : Start over at Step 1.
NO : The procedure is complete.
DTC 57: Accumulator (Accumulator Low-Pressure Abnormality)
.
CIRCUIT OPERATION
The pressure switch (for low-pressure warning) mon-
itors brake fluid pressure inside of the hydraulic
brake booster (HBB). When the brake fluid pressure
decreases abnormally, the pressure switch (for low-
pressure warning) is turned off and the brake fluid
low-pressure warning signal is output to the M-
ASTC-ECU.
.
HBB DTC SET CONDITIONS
DTC 57 is set if the brake fluid pressure decreases,
or the pressure switch (for low-pressure warning)
OFF seize-up occurs. In this case, the M-ASTC-ECU
sounds the buzzer continuously to inform the trouble
of the driver and protects the pump motor by activat-
ing the pump motor intermittently.
.
AC204498AB
Pressure Switch (for Low-Pressure Warning) Circuit
AC204545AB
CONNECTOR: B-17
B-17 (GR)
AC203901AF
CONNECTOR: E-120
E-120