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DTC C2104 Valve Power Supply Circuit
 
 
caution
  • If there is any problem in the CAN bus lines, an incorrect DTC may be set. Prior to this diagnosis, diagnose the CAN bus lines (Refer to GROUP 54C - CAN Bus Diagnostics Table ).
  • Whenever ECU is replaced, ensure that the CAN bus lines are normal.
 
 
OPERATION
  • ASC-ECU contains the power supply circuit (+BV terminal) for the solenoid valve. The solenoid valve is energized by the valve relay, which is incorporated in ASC-ECU.
  • The valve relay, which is incorporated in ASC-ECU, is always energizing 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.
 
 
 
DTC SET CONDITIONS
This DTCs 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 generator
  • ASC-ECU malfunction
Past trouble
  • Carry out diagnosis with particular emphasis on wiring harness and connector failures between the power supply circuit (+BV terminal) to ASC-ECU solenoid valve or ground circuit (GND1, GND2 terminal). For diagnostic procedures, refer to How to treat past trouble (GROUP 00 - How to Use Troubleshooting/How to Treat Past Trouble ).
 
 
 
 
DIAGNOSIS
Required Special Tools:
  • MB991223: Harness Set
STEP 1. Battery check
Refer to GROUP 54A - Battery Test .
  • Also check the terminals for looseness and dirt.
Is the battery in good condition?
Go to Step 2.
Charge or replace or repair the battery (Refer to GROUP 54A - Battery ).
 
STEP 2. Fusible link check: Check the fusible link No.4.
Visually check for open circuit in the fusible link No.4.
Is the check result normal?
Go to Step 4.
Go to Step 3.
 
STEP 3. Resistance measurement at ASC-ECU connector
(1) Disconnect the connector, and measure at the wiring harness side.
(2) Disconnect the fusible link No.4.
(3) Resistance between the +BV terminal and the body ground.
OK: No continuity
Is the check result normal?
Replace the fusible link No.4.
The short circuit may be present in the power supply circuit. Repair the wiring harness between the ASC-ECU connector +BV terminal and the fusible link, and then replace the fusible link No.4.
 
STEP 4. Voltage measurement at the ASC-ECU connector
(1) Disconnect the connector, and measure at the wiring harness side.
(2) Measure the voltage between the +BV terminal and the body ground.
OK: The voltage should measure approximately 12 volts (battery positive voltage)
Is the check result normal?
Go to Step 5.
The open circuit may be present in the power supply circuit. Repair the wiring harness between the ASC-ECU connector +BV terminal and the fusible link No.4.
 
STEP 5. Resistance measurement at ASC-ECU connector
(1) Disconnect the connector, and measure at the wiring harness side.
(2) Resistance between the GND1 terminal and the body ground, and between the GND2 terminal and the body ground.
OK: The resistance should be 2 ohms or less
Is the check result normal?
Go to Step 6.
An open circuit may be present in the ground circuit. Repair the wiring harness between the ASC-ECU connector GND1 terminal and the body ground, and between the ASC-ECU connector GND2 terminal and the body ground.
 
STEP 6. Check whether the DTC is set again.
(1) Erase the DTC.
(2) Turn the ignition switch to the "LOCK" (OFF) position.
(3) Turn the ignition switch to the "ON" position.
Is DTC C2104 set?
Replace the hydraulic unit (integrated with ASC-ECU) (Refer to ).
Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/How to Cope with Intermittent Malfunctions ).