The EV-ECU monitors the brake fluid pressure received from the ASC-ECU via the CAN and
the brake vacuum converted to the voltage by the brake booster vacuum sensor.
DIAGNOSIS CODE SET CONDITIONS
Although there is no brake operation, if the brake vacuum
drops to the brake electric vacuum pump operation set value several times in a short period,
the diagnosis code No. C202B will be set.
note
The slight brake operation to maintain the vehicle speed of approx. 6 km/h
or less may set the diagnosis code.
PROBABLE CAUSES
Malfunction of the vacuum line
Malfunction of the brake fluid pressure sensor
Malfunction of the brake booster vacuum sensor
DIAGNOSIS PROCEDURE
STEP 1. M.U.T.-III data list
Check the service data for the ASC. (Refer to .)
Item No.15 : Master cylinder pressure
Q.
Is the check result normal?
Go to Step 2.
Check if any diagnosis code is set to the ASC (Refer to GROUP 35C - Troubleshooting/Diagnosis
Code Chart ). Then go to Step 4.
STEP 2. Vacuum line check
Check the vacuum line. (Refer to GROUP 35A - On-vehicle Service - Brake
Vacuum Line Check .)
Q.
Is the check result normal?
Go to Step 4.
Check the vacuum hose installation. Then go to Step 3.
STEP 3. BRAKE BOOSTER OPERATION CHECK
Check the operation of the brake booster. (Refer to GROUP 35A - On-vehicle Service - Brake
Booster Operation Check .)
Q.
Is the check result normal?
Go to Step 4.
Replace the brake booster. (Refer to GROUP 35A - Master Cylinder Assembly
and Brake Booster Assembly Removal and Installation <LHD>, <RHD>.)
STEP 4. Check the diagnosis code again.
Check again if the diagnosis code is set to the EV-ECU.
(1)Erase the stored diagnosis code.
(2)Set the electric motor switch from the "LOCK" (OFF) position to the "ON" position.
(3)After 120 seconds, check if the diagnosis code is set.
.)
Go to Step 2.
Check if any diagnosis code is set to the ASC (Refer to GROUP 35C - Troubleshooting/Diagnosis
Code Chart 