Code No.85: Master Cylinder Pressure Sensor Initialisation Incomplete


caution If there is any problem in the CAN bus lines, an incorrect diagnosis code may be set. Diagnose the CAN bus lines before the diagnosis codes (Refer to GROUP 54D, CAN bus-line diagnostic flow ).

DIAGNOSIS CODE SET CONDITIONS

  • When ASTC-ECU is replaced with new one, the master cylinder pressure sensor initialisation must be performed. Diagnosis code No. 85 is set when the initialisation is not performed.
  • The ASTC-ECU finishes the check when it confirms that the output value of the master cylinder pressure sensor changes in the specified response.
  • When the master cylinder pressure sensor is defective or the wiring harness and the connectors are not in good condition, the check will not be completed.

PROBABLE CAUSES
The most likely causes for these diagnosis codes to set are:

  • Damaged wiring harness or connector
  • Master cylinder pressure sensor initialisation is not executed
  • Malfunction of the ASTC-ECU

DIAGNOSIS

STEP 1. M.U.T.-III CAN bus diagnostics
caution Before connecting or disconnecting the M.U.T.-III, turn the ignition switch to the "LOCK" (OFF) position.
(1)Connect M.U.T.-III to the 16-pin diagnosis connector.
(2)Turn the ignition switch to the "ON" position.
(3)Diagnose the CAN bus line.
(4)Turn the ignition switch to the "LOCK" (OFF) position.

Q. Is the check result normal?
Go to Step 3.
Repair the CAN bus line (Refer to GROUP 54D, CAN bus line Diagnostic flow ). Then go to Step 2.

STEP 2. Check whether the diagnosis code is reset.
caution Before connecting or disconnecting the M.U.T.-III, turn the ignition switch to the "LOCK" (OFF) position.
(1)Turn the ignition switch to the "ON" position.
(2)Erase the diagnosis code.
(3)Turn the ignition switch to the "LOCK" (OFF) position.
(4)Turn the ignition switch to the "ON" position.
(5)Check if the diagnosis code is set.
(6)Turn the ignition switch to the "LOCK" (OFF) position.

Q. Is code No.85 set?
Go to Step 3.
The procedure is complete.

STEP 3. Check the diagnosis code again after the master cylinder pressure sensor initialisation.
caution Before connecting or disconnecting the M.U.T.-III, turn the ignition switch to the "LOCK" (OFF) position.
(1)Turn the ignition switch to the "ON" position.
(2)Erase the diagnosis code.
(3)Perform the master cylinder pressure sensor initialisation.
(4)Turn the ignition switch to the "LOCK" (OFF) position.
(5)Turn the ignition switch to the "ON" position.
(6)Check if the diagnosis code is set.
(7)Turn the ignition switch to the "LOCK" (OFF) position.

Q. Is code No.85 set?
Replace the ASTC-ECU.
The procedure is complete.