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DTC P0BC0: Battery warming system power relay short
 
 
cautionBefore replacing the ECU, ensure that the communication circuit is normal.
 
 
MONITOR EXECUTION
  • Continuous
 
 
MONITOR EXECUTION CONDITIONS (Other monitor and Sensor)
Other Monitor (There is no temporary DTC set in memory for the item monitored below)
  • Not applicable
Sensor (The sensor below is determined to be normal)
  • Not applicable
 
 
DTC SET CONDITIONS
Logic Flow Chart
Check Conditions
  • battery management unit (BMU) power supply voltage is 8 volts to 16 volts.
  • Time after above conditions satisfy is more than 1 second.
  • Main drive lithium-ion battery PTC heater main relay ON.
Judgment Criterion
  • The state of the drive lithium-ion battery PTC heater main relay OFF continues for 0.3 second.
 
 
FAIL-SAFE AND BACKUP FUNCTION
  • Not available
 
 
PROBABLE CAUSES
  • The main drive lithium-ion battery PTC heater main relay is failed.
  • The harnesses and connectors are failed.
  • The battery management unit (BMU) is failed.
 
 
 
DIAGNOSIS
Required Special Tools
  • MB991658: Test harness
STEP 1. Check the main drive lithium-ion battery PTC heater main relay.
Check the main drive lithium-ion battery PTC heater main relay (Refer to ).
Is the check result normal?
Go to Step 2.
Replace the main drive lithium-ion battery PTC heater main relay (Refer to ).
 
STEP 2. Measure the resistance at the main drive lithium-ion battery PTC heater main relay connector.
(1) Remove the relay and measure at the wiring harness side.
(2) Check the resistance between main drive lithium-ion battery PTC heater main relay connector (terminal No.1) and body ground.
OK: No continuity
Is the check result normal?
Go to Step 3.
Repair the connector(s) or wiring harness.
 
STEP 3. Using scan tool (M.U.T.-IIISE), check whether the DTC is set again.
Recheck if the DTC is set.
(1) Erase the DTC.
(2) Turn off the power supply mode of the electric motor switch.
(3) Turn on the power supply mode of the electric motor switch.
(4) Set scan tool (M.U.T.-IIISE) to the actuator testing mode for item No.3: BAT. heating system power relay (Refer to ).
  • Main drive lithium-ion battery PTC heater main relay is ON.
(5) Check the DTC is set.
Is the DTC set?
Replace the battery management unit (BMU) (Refer to ).
Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions ).