[Previous][Next]
DTC C1861: Power supply low voltage
 
 
 
 
OPERATION
The electric parking brake ECU is energized from the battery through the fusible links.
 
 
DTC SET CONDITIONS
If the parking brake is not applied or released within a predetermined period due to a low 12V Starter Battery voltage, the DTC will be set.
 
 
TROUBLESHOOTING HINTS
  • Malfunction of the 12V Starter Battery
  • 12V Starter Battery not charged sufficiently or deteriorated
  • Loose or contaminated 12V Starter Battery terminals
  • Open or ground fault in the electric parking brake ECU power supply circuit.
  • Malfunction of the electric parking brake ECU
 
 
DIAGNOSIS
Required Special Tools:
  • MB992006: Extra Fine Probe
STEP 1. Check the 12V Starter Battery.
Refer to GROUP 54A - 12V Starter Battery Test .
Is the check result normal?
Go to Step 2.
Charge or replace the 12V Starter Battery (Refer to GROUP 54A - 12V Starter Battery ). Then go to Step 2.
 
STEP 2. Measure the resistance at the electric parking brake ECU connector.
(1) Disconnect the connector and measure at the wiring harness side.
(2) Measure the resistance between GND1 terminal and ground.
OK: The resistance should be 2 ohms or less
(3) Measure the resistance between GND2 terminal and ground.
OK: The resistance should be 2 ohms or less
Is the check result normal?
Go to Step 3.
The ground circuit may be open. Repair the wiring harness wires or connectors between the electric parking brake ECU connector and the ground.
 
STEP 3. Measure the voltage at the electric parking brake ECU connector.
(1) Disconnect the electric parking brake ECU connector and measure at the wiring harness side.
(2) Measure the voltage between the +ECU terminal and ground.
OK: The voltage should measure approximately 12 volts (battery positive voltage).
Is the check result normal?
Go to Step 4.
The power supply circuit may be open. Repair the wiring harness wires or connectors between the electric parking brake ECU connector and the fusible link.
 
STEP 4. Check whether the DTC is set again.
(1)
cautionTo prevent damage to scan tool (M.U.T.-IIISE), always turn off the power supply mode of the electric motor switch before connecting or disconnecting scan tool (M.U.T.-IIISE).
Connect scan tool (M.U.T.-IIISE). Refer to "How to connect the Scan Tool (M.U.T.-IIISE) ."
(2) Erase the DTC.
(3) Turn off the power supply mode of the electric motor switch.
(4) Turn on the power supply mode of the electric motor switch.
(5) Operate the electric parking brake switch to apply and then release the electric parking brake.
(6) Check if the DTC is set.
Is DTC No. C1861 set?
Replace the electric parking brake ECU (Refer to ).
The trouble can be an intermittent malfunction (GROUP 00 - How to use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunction ).