Code No.61: Master Cylinder Pressure Sensor System

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

OPERATION

HBB, which is provided with the master cylinder pressure sensor, converts the master cylinder pressure input from the brake pedal into voltage value, and outputs it to ASTC-ECU.

DIAGNOSIS CODE SET CONDITIONS

Diagnosis code No. 61 is set in the following cases;

Abnormal rise or drop of input voltage
Abnormal rise or drop of output voltage
When the pressure value does not vary while the stop lamp switch signal is ON.
When the pressure value is output while the stop lamp switch signal is OFF.
When a steady pressure value is always output during driving.

PROBABLE CAUSES

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

Damaged wiring harness or connector
Malfunction of the master cylinder pressure sensor
Malfunction of the ASTC-ECU
Incorrect adjustment of the stop lamp switch
Malfunction of the stop lamp switch
Malfunction of brake pedal
Malfunction of the HBB

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)Disconnect the M.U.T.-III.

(6)Drive the vehicle more than 60 seconds at the speed exceeds 10 km/h. Stop the vehicle by braking from the speed exceeds 40 km/h.

(7)Check if the diagnosis code is set.

(8)Turn the ignition switch to the "LOCK" (OFF) position.

Q. Is code No.61 set?

	Go to Step 3.

	The procedure is complete.

STEP 3. Check master cylinder pressure sensor connector B-110 and ASTC-ECU connector D-232 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q. Is the check result normal?

	Go to Step 4.

	Repair or replace the damaged component(s). Then go to Step 13.

STEP 4. Check the power supply circuit at pressure sensor connector B-110.

(1)Do not disconnect pressure sensor connector B-110.

(2)Turn the ignition switch to the "ON" position.

(3)Measure voltage between terminal 2 and earth.
OK: Approximately 5 V

Q. Is the voltage approximately 5 volts?

	Go to Step 7.

	Go to Step 5.

STEP 5. Check the ASTC-ECU connector D-232.

(1)Disconnect the ASTC-ECU connector D-232, and measure at the ASTC-ECU side.

(2)Turn the ignition switch to the "ON" position.

(3)Measure voltage between terminal 50 and earth.
OK: Approximately 5 V

Q. Is the check result normal?

	Go to Step 6.

	Replace the ASTC-ECU. Then go to Step 13.

STEP 6. Check the harness wires between master cylinder pressure sensor connector B-110 terminal 2 and ASTC-ECU connector D-232 terminal 50.

Q. Is the check result normal?

	Repair the wiring harness. Then go to Step 13.

	It can be assumed that this malfunction is intermittent. Refer to GROUP 00, How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunction .

STEP 7. Check the earth circuit at pressure sensor connector B-110.

(1)Disconnect pressure sensor connector B-110, and measure at the harness side.

(2)Measure the resistance between terminal 3 and earth.
OK: Continuity exists (2 Ω or less)

Q. Is the check result normal?

	Go to Step 10.

	Go to Step 8.

STEP 8. Check the ASTC-ECU connector D-232.

(1)Disconnect the ASTC-ECU connector D-232, and measure at the ASTC-ECU side.

(2)Measure the resistance between terminal 49, 58 and earth.
OK: Continuity exists (2 Ω or less)

Q. Is the check result normal?

	Go to Step 9.

	Replace the ASTC-ECU. Then go to Step 13.

STEP 9. Check the harness wires between master cylinder pressure sensor connector B-110 terminal 3 and ASTC-ECU connector D-232 terminal 49 and 58.

Q. Is the check result normal?

	Repair the wiring harness. Then go to Step 13.

	It can be assumed that this malfunction is intermittent. Refer to GROUP 00, How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunction .

STEP 10. Check the master cylinder pressure sensor connector B-110.

(1)Disconnect the master cylinder pressure sensor connector B-110, and measure at the master cylinder pressure sensor side.

(2)Turn the ignition switch to the "ON" position.

(3)Measure voltage between terminal 1 and earth.
OK: 0.14 - 4.85 V

Q. Is the check result normal?

	Go to Step 11.

	Replace the HBB. Then go to Step 13.

STEP 11. Check the ASTC-ECU connector D-232.

(1)Disconnect the ASTC-ECU connector D-232, and measure at the harness side.

(2)Turn the ignition switch to the "ON" position.

(3)Measure voltage between terminal 59 and earth.
OK: 0.14 - 4.85 V

Q. Is the check result normal?

	Replace the ASTC-ECU. Then go to Step 13.

	Go to Step 12.

STEP 12. Check the harness wires between master cylinder pressure sensor connector B-110 terminal 2 and ASTC-ECU connector D-232 terminal 50.

Q. Is the check result normal?

	Repair the wiring harness. Then go to Step 13.

	It can be assumed that this malfunction is intermittent. Refer to GROUP 00, How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunction .

STEP 13. Check whether the diagnosis code is reset.

(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.61 set?

	Repeat the troubleshooting from Step 1.

	The procedure is complete.