[Previous][Next]
DTC C1860: Power supply high voltage
 
 
caution
  • If there is any problem in the CAN bus lines, an incorrect diagnostic trouble code (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
  • Power is supplied to the EPS-ECU from the battery or the ignition switch.
 
 
DIAGNOSTIC TROUBLE CODE SET CONDITION
The power supply voltage is more than a predetermined voltage stored in the microcomputer, and the microcomputer determines that there is a problem in the power supply system.
 
 
PROBABLE CAUSES
  • Malfunction of CAN bus line
  • Defective battery
  • Charging system failed
  • Malfunction of the EPS-ECU
 
 
DIAGNOSIS
STEP 1. Using scan tool (M.U.T.-III), diagnose the CAN bus lines.
Use scan tool (M.U.T.-III) to diagnose the CAN bus lines.
Is the check result normal?
Go to Step 3.
Repair the CAN bus lines (Refer to GROUP 54C - CAN Bus Diagnostics Table ). On completion, go to Step 2.
 
STEP 2. Diagnostic trouble code recheck after resetting CAN bus lines
(1) Erase the diagnostic trouble code.
(2) Turn the ignition switch from the "LOCK" (OFF) position to the "ON" position.
(3) Check if the diagnostic trouble code is set.
Is DTC C1860 set?
Go to Step 3.
This diagnosis is complete.
 
STEP 3. Check the battery voltage.
Start the engine and measure the battery voltage (Refer to GROUP 54A - Battery ).
Is the check result normal?
Go to Step 4.
Check the battery and repair if necessary (Refer to GROUP 54A - Battery , ). Then go to Step 7.
 
STEP 4. Check the charging system.
Start the engine and measure the charging system (Refer to GROUP 16 - Charging System, On-vehicle Service/Generator Output Line Voltage Drop Test ).
Is the check result normal?
Go to Step 5.
Check the charging system and repair if necessary (Refer to GROUP 16 - Generator Assembly ). Then go to Step 7.
 
STEP 5. Using scan tool (M.U.T.-III), check data list.
Check the following data list .
  • Item No. 22: Power relay voltage
  • Item No. 23: Ignition voltage
Is the check result normal?
Go to Step 7.
Go to Step 6.
 
STEP 6. Check whether the diagnostic trouble code is set again.
(1) Erase the diagnostic trouble code.
(2) Turn the ignition switch from the "LOCK" (OFF) position to the "ON" position.
(3) Check if the diagnostic trouble code is set.
Is DTC C1860 set?
Replace the EPS-ECU (Refer to ). Then go to Step 7.
Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points, How to Cope with Intermittent Malfunctions ).
 
STEP 7. Check whether the diagnostic trouble code is set again.
(1) Erase the diagnostic trouble code.
(2) Turn the ignition switch from the "LOCK" (OFF) position to the "ON" position.
(3) Check if the diagnostic trouble code is set.
Is DTC C1860 set?
Return to Step 1.
This diagnosis is complete.