Code No. C2021: Brake booster vacuum sensor failure output voltage (VP)


BRAKE BOOSTER VACUUM SENSOR CIRCUIT









OPERATION



DIAGNOSIS CODE SET CONDITIONS



  • If the setting range deviation of the brake booster vacuum sensor output voltage continues, the diagnosis code No. C2021 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: 0.1 to 4.5 V

Q. Is the check result normal?
Go to Step 4.
Go to Step 2.

STEP 2. Connector check: C-106 EV-ECU connector, B-28 intermediate connnector, A-105 brake booster vacuum sensor connector

Q. I s 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. 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)Check if the diagnosis code is set.

Q. Is the diagnosis code set?
Replace the brake booster vacuum sensor. (Refer to GROUP 35A - Master Cylinder Assembly and Brake Booster Assembly <LHD>, <RHD>.) Then go to Step 5.
Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunction .)

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)Check if the diagnosis code is set.

Q. Is the diagnosis code set?
Replace the EV-ECU. (Refer to .) Then go to Step 6.
The diagnosis is complete.

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)Check if the diagnosis code is set.

Q. Is the diagnosis code set?
Return to Step 1.
The diagnosis is complete.