Code No. C2104 Faulty valve power supply circuit






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 - CAN Bus Diagnostics Table ).

OPERATION

  • ABS-ECU contains the power supply circuit (terminal No. 26) for the solenoid valve. The solenoid valve is energised by the valve relay, which is incorporated in ABS-ECU.
  • The valve relay, which is incorporated in ABS-ECU, is always energising the solenoid valve unless the initial check is in progress when the ignition switch is turned on, and the recurrent system check is in progress.

DIAGNOSIS CODE SET CONDITIONS
This diagnosis code will be set when the solenoid valve supply voltage is not within the standard value.

PROBABLE CAUSES
Current trouble
  • Fusible link malfunction
  • Damaged wiring harness and connectors
  • Abnormality in battery or alternator
  • ABS-ECU malfunction
Past trouble
  • Carry out diagnosis with particular emphasis on wiring harness and connector failures between the power supply circuit (terminal No.26) to ABS-ECU solenoid valve or earth circuit (terminal No.14). For diagnosis procedures, refer to How to treat past trouble (GROUP 00 - How to Use Troubleshooting/How to Treat Past Trouble ).

DIAGNOSTIC 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 Diagnostics Table ). On completion, go to Step 2.

STEP 2. Diagnosis code recheck after resetting CAN bus lines

Q. Is the diagnosis code No.C2104 set?
Go to Step 3.
This diagnosis is complete.

STEP 3. Battery check
Refer to GROUP 54A - Battery Test .

Q. Is the battery in good condition?
Go to Step 4.
Replace the battery. Then go to Step 11.

STEP 4. Charging system check
Refer to GROUP 16 - On-vehicle Service/Alternator Output Line Voltage Drop Test .

Q. Is the charging system in good condition?
Go to Step 5.
Repair or replace the charging system component(s). Then go to Step 11.

STEP 5. Connector check: A-02 ABS-ECU connector

Q. Is the check result normal?
Go to Step 6.
NO : Repair the defective connector. Then go to Step 11.

STEP 6. Fusible link check: Check the fusible link No.27.
Visually check for open circuit in the fusible link No.27.

Q. Is the check result normal?
Go to Step 8.
Go to Step 7.

STEP 7. Resistance measurement at A-02 ABS-ECU connector

(1)Disconnect the ABS-ECU connector, connect special tool ABS check harness (MB991974) to the harness-side connector, and then measure the resistance at the special tool connector side.
note Do not connect the special tool ABS check harness (MB991974) to ABS-ECU.
(2)Disconnect the fusible link No.27.
(3)Resistance between the terminal No.26 and the body earth.
OK: No continuity

Q. Is the check result normal?

Replace the fusible link No.27. Then go to Step 11.

The short circuit may be present in the power supply circuit. Repair the wiring harness between the A-02 ABS-ECU connector terminal No.26 and the fusible link No.27, and then replace the fusible link No.27. Then go to Step 11.

STEP 8. Voltage measurement at the A-02 ABS-ECU connector

(1)Disconnect the ABS-ECU connector, connect special tool ABS check harness (MB991974) to the harness-side connector, and then measure the resistance at the special tool connector side.
note Do not connect the special tool ABS check harness (MB991974) to ABS-ECU.
(2)Measure the voltage between the terminal No.26 and the body earth.
OK: Approximately system voltage

Q. Is the check result normal?

Go to Step 9.

The open circuit may be present in the power supply circuit. Repair the wiring harness between the A-02 ABS-ECU connector terminal No.26 and the fusible link No.27. Then go to Step 11.

STEP 9. Resistance measurement at A-02 ABS-ECU connector

(1)Disconnect the ABS-ECU connector, connect special tool ABS check harness (MB991974) to the harness-side connector, and then measure the resistance at the special tool connector side.
note Do not connect the special tool ABS check harness (MB991974) to ABS-ECU.
(2)Resistance between the terminal No.1 and the body earth, and between the terminal No.14 and the body earth
OK: Continuity exists (2 Ω or less)

Q. Is the check result normal?

Go to Step 10.

An open circuit may be present in the earth circuit. Repair the wiring harness between the A-02 ABS-ECU connector terminal No.1 and the body earth, and between the A-02 ASC-ECU connector terminal No.14 and the body earth. Then go to Step 11.

STEP 10. Check whether the diagnosis code is reset.
Erase the diagnosis code.

Q. Is the diagnosis code No.C2104 set?
Replace the hydraulic unit (integrated with ABS-ECU) (Refer to ). Then go to Step 11.
Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/ How to Cope with Intermittent Malfunctions ).

STEP 11. Check whether the diagnosis code is reset.
Erase the diagnosis code.

Q. Is the diagnosis code No.C2104 set?
Return to Step 1.
This diagnosis is complete.