C2104
DTC C2104: Malfunction of power supply circuit
CAUTION
If there is any problem in the CAN bus lines, an incorrect diagnostic trouble code may be set. Prior to this diagnosis, diagnose the CAN bus lines.
CIRCUIT OPERATION
^ ABS-ECU contains the power supply circuit (terminal No.26) for the solenoid valve. The solenoid valve is energized by the valve relay, which is incorporated in ABS-ECU.
^ The valve relay, which is incorporated in ABS-ECU, is always energizing 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.
DTC SET CONDITIONS
This diagnostic trouble codes will be set under the conditions below: 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
^ 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 ground circuit (terminal No. 1).
DIAGNOSIS
Required Special Tools:
^ MB991958: Scan Tool (M.U.T-III Sub Assembly)
^ MB991824: Vehicle Communication Interface (V.C.I.)
^ MB991827: M.U.T.-III USB Cable
^ MB991910: M.U.T.-III Main Harness A
^ MB991974: ABS check harness
STEP 1. M.U.T.-III CAN bus diagnostics
Use scan tool to diagnose the CAN bus lines.
Q: Is the check result normal?
YES: Go to Step 3.
NO: Repair the CAN bus lines. On completion, go to Step 2.
STEP 2. Diagnostic trouble code recheck after resetting CAN bus lines
Q: Is DTC C2104 set?
YES: Go to Step 3.
NO: The procedure is complete.
STEP 3. Fusible link check: Check fusible link No.27.
Visually check for open circuit in fusible link No.27.
Q: Is the check result normal?
YES: Go to Step 4.
NO: Replace fusible link No.27.
STEP 4. Battery check
Q: Is the battery in good condition?
YES: Go to Step 5.
NO: Charge or replace the battery.
STEP 5. Charging system check
Q: Is the charging system in good condition?
YES: Go to Step 6.
NO: Repair or replace the charging system component(s).
STEP 6. Voltage measurement at the A-03 ABS-ECU connector
1) Disconnect the connector, connect special tool MB991974 to the harness-side connector, and measure the voltage at the special tool connector side.
NOTE: Do not connect the special tool MB991974 to ABS-ECU.
2) Turn the ignition switch to the ON position.
3) Measure the voltage between terminal No.26 and body ground.
OK: Approximately battery voltage
Q: Is the check result normal?
YES: Go to Step 8.
NO: Go to Step 7.
STEP 7. Connector check: A-03 ABS-ECU connector
Q: Is the check result normal?
YES: An open or short circuit may be present in the power supply circuit. Repair the wiring harness between the A-03 ABS-ECU connector terminal No.26 and fusible link No.27.
NO: Repair the defective connector.
STEP 8. Resistance measurement at A-03 ABS-ECU connector
1) Disconnect the connector, connect special tool MB991974 to the harness-side connector, and measure the resistance at the special tool connector side.
NOTE: Do not connect the special tool MB991974 to ABS-ECU.
2) Resistance between the terminal No. 1 and body ground, and between terminal No. 14 and body ground.
OK: Continuity exists (2 Ohms or less)
Q: Is the check result normal?
YES: Go to Step 10.
NO: Go to Step 9.
STEP 9. Connector check: A-03 ABS-ECU connector
Q: Is the check result normal?
YES: An open circuit may be present in the ground circuit. Repair the wiring harness between the A-03 ABS-ECU connector terminal No. 1 and body ground, and between the A-03 ABS-ECU connector terminal No. 14 and body ground.
NO: Repair the defective connector.
STEP 10. Check whether the diagnostic trouble code is reset.
Q: Is DTC C2104 set?
YES: Replace the ABS-ECU.
NO: Intermittent malfunction.