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DTC C2100: Power Supply Low Voltage
 
 
caution
  • If there is any problem in the CAN bus lines, an incorrect DTC may be stored. Prior to this diagnosis, diagnose the CAN bus lines.
  • Whenever the ECU is replaced, ensure that the communication circuit is normal.
 
 
OPERATION
AWC-ECU power supply is provided from the battery via ETACS-ECU.
 
 
DTC SET CONDITIONS
When the conditions below are satisfied at the system start-up, the drive train will be switched from AWD to FWD gradually. Then diagnostic trouble code No.C2100 will be stored.
  • Voltage between the battery and ETACS-ECU: Less than 9 V
  • IG1 Voltage: Less than 9 V
 
 
PROBABLE CAUSES
  • Battery failure
  • Malfunction of charging system
  • Malfunction of ETACS-ECU (power supply circuit system)
  • Damaged harness wires and connectors
  • Malfunction of electronic control coupling solenoid (front, center)
  • Malfunction of AWC-ECU
 
 
DIAGNOSTIC PROCEDURE
STEP 1. Scan tool (M.U.T.-III) other system DTC.
Check the ETACS DTC (Refer to GROUP 54A - Diagnosis, Diagnostic Trouble Code Chart ).
Is the DTC stored?
Perform the relevant troubleshooting.
Go to Step 2.
 
STEP 2. Check the battery.
Refer to GROUP 54A - Battery Test .
Is the check result normal?
Go to Step 4.
Charge or replace the battery. Then go to Step 3.
 
STEP 3. Check the charging system.
Refer to GROUP 16 - Charging System .
Is the check result normal?
Go to Step 4.
Repair or replace the charging system component(s).
 
STEP 4. Voltage measurement at AWC-ECU connector
Disconnect the connector, and measure the voltage between terminal BATT and body ground at the wiring harness side.
OK: Battery positive voltage
Is the check result normal?
Go to Step 6.
Repair the defective connector or the wiring harness. Then go to Step 5.
 
STEP 5. Scan tool (M.U.T.-III) data list.
Check the following data list (Refer to ).
  • Item No.31: Battery voltage (CAN input)
Is the check result normal?
Intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent Malfunction ).
Replace the ETACS-ECU. Then go to Step 10.
 
STEP 6. Measure the resistance at the AWC-ECU connector.
(1) Disconnect the connector, and measure at the wiring harness side.
(2) Resistance between AWC-ECU connector terminal GND1 and body ground.
OK: Continuity exists (2 Ω or less)
Is the check result normal?
Go to Step 8.
Go to Step 7.
 
STEP 7. Check the wiring harness between AWC-ECU connector terminal GND1 and body ground.
Check the ground line for open circuit.
Is the check result normal?
Intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent Malfunction ).
Repair the defective connector or the wiring harness. Then go to Step 15.
 
STEP 8. Measure the resistance at the AWC-ECU connector.
(1) Disconnect the connector, and measure at the wiring harness side.
(2) Resistance between AWC-ECU connector terminal FSL+, FSL- and body ground
OK: No continuity
Is the check result normal?
Go to Step 10.
Go to Step 9.
 
STEP 9. Check the wiring harness between electronic control coupling solenoid (front) connector and AWC-ECU connector terminal FSL+, FSL-.
Check the power supply, ground line for short circuit.
Is the check result normal?
Intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent Malfunction ).
Repair the defective connector or the wiring harness. Then go to Step 15.
 
STEP 10. Check of the electronic control coupling solenoid (front)
Refer to .
Is the check result normal?
Go to Step 11.
Replace the transfer assembly (Refer to ). Then go to Step 15.
 
STEP 11. Measure the resistance at the AWC-ECU connector.
(1) Disconnect the connector, and measure at the wiring harness side.
(2) Resistance between AWC-ECU connector terminal SOL+, SOL- and body ground
OK: No continuity
Is the check result normal?
Go to Step 13.
Go to Step 12.
 
STEP 12. Check the wiring harness between electronic control coupling solenoid (center) connector and AWC-ECU connector terminal SOL+, SOL-.
Check the power supply, ground line for short circuit.
Is the check result normal?
Intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent Malfunction ).
Repair the defective connector or the wiring harness. Then go to Step 13.
 
STEP 13. Check of the electronic control coupling solenoid (center)
Refer to GROUP 27C - On-vehicle Service .
Is the check result normal?
Go to Step 14.
Replace the electronic control coupling (center) (Refer to GROUP 27C - Electronic Control Coupling ). Then go to Step 15.
 
STEP 14. Scan tool (M.U.T.-III) data list.
Check the following data list (Refer to ).
  • Item No.31: Battery voltage (CAN input)
Is the check result normal?
Intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent Malfunction ).
Replace the AWC-ECU (Refer to ). Then go to Step 15.
 
STEP 15. Check whether the DTC is stored again.
Is DTC No.C2100 stored?
Return to Step 1.
This diagnosis is complete.