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, Trouble code diagnosis ).

OPERATION

  • ASC-ECU contains the power supply circuit (terminal No. 32) for the solenoid valve. The solenoid valve is energised by the valve relay, which is incorporated in ASC-ECU.
  • The valve relay, which is incorporated in ASC-ECU, is always energising the solenoid valve unless the initial check is in progress when the ignition switch is turned on, or the recurrent system check is in progress.

DIAGNOSIS CODE SET CONDITIONS
This diagnosis codes will be set under the cases below:

  • When the solenoid valve supply voltage is not within the standard value.
  • When the solenoid valve supply voltage is lower than the ECU power supply voltage.

PROBABLE CAUSES
Current trouble
  • Fusible link malfunction
  • Damaged wiring harness and connectors
  • Abnormality in battery or alternator
  • ASC-ECU malfunction
Past trouble
  • Carry out diagnosis with particular emphasis on wiring harness and connector failures between the power supply circuit (terminal No. 32) to ASC-ECU solenoid valve or earth circuit (terminal No. 16). For diagnosis procedures, refer to How to treat past trouble (GROUP 00 - How to Cope with Intermittent Malfunction ).

DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-III CAN bus diagnosiss
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 - Troubleshooting ). 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. 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 4.
Replace the fusible link No.27.

STEP 4. Battery check
Refer to GROUP 54A - Battery Test .

Q. Is the battery in good condition?
Go to Step 5.
Charge or replace the battery.

STEP 5. Charging system check
Refer to GROUP 16 - Charging System .

Q. Is the charging system in good condition?
Go to Step 6.
Repair or replace the charging system component(s).

STEP 6. Voltage measurement at the A-03 ASC-ECU connector

(1)Disconnect the ASC-ECU connector, connect special tool ASC check harness (MB991997) to the harness-side connector, and then measure the voltage at the special tool connector side.
note Do not connect the special tool ASC check harness (MB991997) to ASC-ECU.
(2)Turn the ignition switch to the ON position.
(3)Measure the voltage between the terminal No. 32 and the body earth.
OK: Approximately battery voltage

Q. Is the check result normal?

Go to Step 8.

Go to Step 7.

STEP 7. Connector check: A-03 ASC-ECU connector

Q. Is the check result normal?
The open or short circuit may be present in the power supply circuit. Repair the wiring harness between the A-03 ASC-ECU connector terminal No. 32 and the fusible link No. 27.
NO : Repair the defective connector.

STEP 8. Resistance measurement at A-03 ASC-ECU connector

(1)Disconnect the ASC-ECU connector, connect special tool ASC check harness (MB991997) to the harness-side connector, and then measure the resistance at the special tool connector side.
note Do not connect the special tool ASC check harness (MB991997) to ASC-ECU.
(2)Resistance between the terminal No. 16 and the body earth
OK: Continuity exists (2 Ω or less)

Q. Is the check result normal?

Go to Step 10.

Go to Step 9.

STEP 9. Connector check: A-03 ASC-ECU connector

Q. Is the check result normal?
An open circuit may be present in the earth circuit. Repair the wiring harness between the A-03 ASC-ECU connector terminal No. 16 and the body earth.
NO : Repair the defective connector.

STEP 10. Check whether the diagnosis code is reset.

Q. Is the diagnosis code No. C2104 set?
Replace the ASC-ECU.
Intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent Malfunction ).