Code No. C1009 Low brake fluid level












caution
  • If there is any problem in the CAN bus lines, an incorrect diagnosis code may be set. Prior to this diagnosis, diagnose the CAN bus lines (Refer to GROUP 54C, Trouble code diagnosis ).
  • Whenever ECU is replaced, ensure that the CAN bus lines are normal.
  • When the hydraulic unit (integrated with ASC-ECU) is replaced, always carry out the calibration of the steering wheel sensor, the G and yaw rate sensor and brake fluid pressure sensor (Refer to , and ).

OPERATION
ASC-ECU receives the ON signal of the brake fluid level switch in ETACS-ECU via the CAN bus lines. This indicates that the brake fluid level is lower than the specified.

DIAGNOSIS CODE SET CONDITIONS
This diagnosis code is set when the brake fluid level is lower than the specified.

PROBABLE CAUSES

  • Low brake fluid level
  • Brake fluid level switch malfunction
  • Brake pad wear
  • Damaged wiring harness and connectors
  • Malfunction of ETACS-ECU
  • ASC-ECU malfunction

DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-III CAN bus diagnostics
Use M.U.T.-III to diagnose the CAN bus lines.

Q. Is the check result normal?
Go to Step 3.
Repair the CAN bus lines (Refer to GROUP 54C - CAN Bus Diagnosis table ). On completion, go to Step 2.

STEP 2. Diagnosis code recheck after resetting CAN bus lines

Q. Is diagnosis code No.C1009 set?
Go to Step 3.
This diagnosis is complete.

STEP 3. Brake fluid level check
Check that the brake fluid level is higher than the lower limit.

Q. Is the check result normal?
Go to Step 5.
Go to Step 4.

STEP 4. Brake pad check
Check that the brake pad is thicker than the limit (Refer to GROUP 35A - On-vehicle Service ).

Q. Is the check result normal?
Check and repair brake tube and brake hose, and then add brake fluid as necessary. Then go to Step 11.
Replace the brake pad (Refer to GROUP 35A - On-vehicle Service ), and then add brake fluid as necessary. Then go to Step 11.

STEP 5. Brake fluid level switch check
Refer to GROUP 35A - On-vehicle Service .

Q. Is the check result normal?
Go to Step 6.
Replace the reservoir assembly (Refer to GROUP 35A - Master Cylinder Assembly and Brake Booster ). Then go to Step 11.

STEP 6. Resistance measurement at A-10 brake fluid level switch connector
(1)Disconnect the A-10 brake fluid level switch connector, and then measure the resistance at the harness connector side.
(2)Resistance between the A-10 brake fluid level switch connector terminal No.2 and the body earth.
OK: Continuity exists (2 Ω or less)

Q. Is the check result normal?
Go to Step 7.
Check and repair the harness wire between the A-10 brake fluid level switch connector terminal No.2 and the body earth.

STEP 7. Resistance measurement between C-312 ETACS-ECU connector and A-10 brake fluid level switch connector
(1)Disconnect C-312 ETACS-ECU connector and A-10 brake fluid level switch connector, and then measure the resistance at the harness connector side.
(2)Resistance between the C-312 ETACS-ECU connector terminal No.1 and A-10 brake fluid level switch connector terminal No.1.
OK: Continuity exists (2 Ω or less)

Q. Is the check result normal?
Go to Step 8.
Check and repair the harness wire between the C-312 ETACS-ECU connector terminal No.1 and A-10 brake fluid level switch connector terminal No.1.

STEP 8. Voltage measurement at C-312 ETACS-ECU connector
(1)Do not disconnect the connector.
(2)Turn the ignition switch to the ON position.
(3)Measure the voltage between the terminal No.1 and the body earth to the back probing.
OK: Approximately 0 volts

Q. Is the check result normal?
Go to Step 9.
Open circuit between the harness wire C-312 ETACS-ECU connector terminal No.1 and A-10 brake fluid level switch connector terminal No.1 may be present. Repair the harness wire between the C-312 ETACS-ECU connector terminal No.1 and A-10 brake fluid level switch connector terminal No.1.

STEP 9. M.U.T.-III data list
Check the following service data (Refer to ).

  • Item 26: Brake fluid level switch

Q. Is the check result normal?
Go to Step 10.
Replace the ETACS-ECU (Refer to GROUP 54A - ETACS-ECU ), and then go to Step 11.

STEP 10. Check whether the diagnosis code is reset.
(1)Ignition switch "LOCK" (OFF)
(2)Ignition switch "ON"

Q. Is diagnosis code No.1009 set?
Replace the ASC-ECU (Refer to ). Then go to Step 11.
The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent Malfunction ).

STEP 11. Check whether the diagnosis code is reset.
(1)Ignition switch "LOCK" (OFF)
(2)Ignition switch "ON"

Q. Is diagnosis code No.1009 set?
Return to Step 1.
This diagnosis is complete.