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DTC P0BC1: BATT. Warming PWR. Relay Stuck ON
cautionWhenever ECU is replaced, ensure that the CAN bus lines are normal.
 
 
 
 
MONITOR EXECUTION
  • Once per driving cycle
 
 
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 less than 4 second or less than 2.7 second (Propulsion system active or Charge system active).
  • Main drive lithium-ion battery PTC heater main relay OFF.
  • Main drive lithium-ion battery cooling fan drive request is on (Active command).
Judgment Criterion
  • The state of the main drive lithium-ion battery cooling fan drive status continues for 0.5 seconds.
 
 
FAIL-SAFE AND BACKUP FUNCTION
  • Not available
 
 
PROBABLE CAUSES
  • The main drive lithium-ion battery PTC heater main relay is failed.
  • Short circuits to power supply system of main drive lithium-ion battery cooling fan circuit; poor contact of connector.
  • 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 power supply voltage at D-32 main drive lithium-ion battery connector.
(1) Disconnect the connector, and measure at the wiring harness side.
(2) Turn on the power supply mode of the electric motor switch without depressing the brake pedal.
noteWhen depressing the brake pedal and turning on the power supply mode (Ready operation), the main drive lithium-ion battery PTC heater turns ON and it is impossible to measure normally.
(3) Check the voltage between the D-32 main drive lithium-ion battery connector (terminal No.3) and body ground.
OK: Approximately 0 volt
(4) Turn off the power supply mode of the electric motor switch.
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 the data list. <BMU (SUB)>
(1) Turn on the power supply mode of the electric motor switch.
(2) Check the BMU (SUB) data list (Refer to ).
  • Item No.7: Battery cooling fan rotations
Is the check result normal?
Go to Step 7.
Go to Step 4.
 
STEP 4. Resistance measurement at BMU connector.
(1) Remove the BMU, and measure at the equipment side.
(2) Resistance between D-203 BMU connector terminal No.37 and 38.
OK: 120 ± 20 Ω
Is the check result normal?
Go to Step 5.
Replace the battery management unit (BMU) (Refer to ).
 
STEP 5. Check of short to power supply circuit and damage in the main drive lithium-ion battery harness.
(1) Remove the battery tray cover (Refer to ).
(2) Remove the main drive lithium-ion battery harness (Refer to ).
(3) Check there is no short to power supply point in main drive lithium-ion battery harness.
Is the check result normal?
Go to Step 6.
Repair the connector(s) or wiring harness. Then, assemble the main drive lithium-ion battery assembly (Refer to ).
 
STEP 6. Resistance measurement at CMU7 connector.
(1) Disconnect the CMU7 connector, and measure at the equipment side.
(2) Resistance between CMU7 connector terminal No.3 and 5.
OK: 120 ± 20 Ω
Is the check result normal?
Replace the sub battery management unit [BMU (SUB)] (Refer to ). Then, assemble the main drive lithium-ion battery assembly (Refer to ).
Replace the CMU07. Then, assemble the main drive lithium-ion battery assembly (Refer to ).
 
STEP 7. 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) Check if 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 ).