Code No. C2022: Brake booster vacuum sensor output value seizure (VP)

BRAKE BOOSTER VACUUM SENSOR CIRCUIT

OPERATION

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

If there is no change in the output of the brake booster vacuum sensor during operating the brake or driving the brake electric vacuum pump, the diagnosis code No. C2022 will be set.

PROBABLE CAUSES

Damaged wiring harness or connector(s)
Malfunction of the brake booster vacuum sensor
Malfunction of the EV-ECU

DIAGNOSIS PROCEDURE

STEP 1. Voltage measurement at C-106 EV-ECU connector

(1)With the C-106 EV-ECU connector connected, and measure by backprobing.

(2)Turn the electric motor switch to the "ON" position.

(3)Measure the brake booster vacuum sensor output voltage between the C-106 EV-ECU connector terminal No. 34 and the body earth.
OK: 0.2 to 1.7 V

Q. Is the check result normal?

	Go to Step 4.

	Go to Step 2.

STEP 2. Connector check: C-106 EV-ECU connector, A-105 brake booster vacuum sensor connector

Q. Is the check result normal?

	Go to Step 3.

	Repair the damaged connector.

STEP 3. Check the wiring harness between A-105 brake booster vacuum sensor connector terminal No. 1 and C-106 EV-ECU connector terminal No. 34.

Check the signal lines for open circuit and short to earth.

Q. Is the check result normal?

	Go to Step 4.

	Repair the wiring harness.

STEP 4. M.U.T.-III data list

Check the service data for the brake booster vacuum sensor. (Refer to

Item No. 250 : VP: Vacuum sensor value

Q. Is the check result normal?

	Go to Step 5.

	Replace the brake booster vacuum sensor. (Refer to GROUP 35A - Master Cylinder Assembly and Brake Booster Assembly <LHD>, <RHD>.) Then go to Step 5.

STEP 5. Diagnosis code recheck

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)Depress the brake pedal fully three or more times.

(4)Check if the diagnosis code is set.

Q. Is the diagnosis code set?

	Replace the EV-ECU. (Refer to .) Then go to Step 6.

	Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunction .)

STEP 6. Diagnosis code recheck

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)Depress the brake pedal fully three or more times.

(4)Check if the diagnosis code is set.

Q. Is the diagnosis code set?

	Return to Step 1.

	The diagnosis is complete.

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