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DTC No. P1B04-12 Fail Safe Relay Hardwire Hi side stiction diagnosis
 
 
 
 
DTC SET CONDITION
Check Condition
  • During the BMU operation
Judgment Criterion
  • The main contactor forcible shut-off signal of the BMU is detected to be stuck on Hi side.
 
 
TROUBLESHOOTING HINTS
  • Damaged wiring harness and connectors
  • Malfunction of the PHEV-ECU
  • Malfunction of the BMU
 
 
DIAGNOSIS
Required Special Tools:
  • MB992744: Vehicle communication interface-Lite (V.C.I.-Lite)
  • MB992745: V.C.I.-Lite main harness A
  • MB992747: V.C.I.-Lite USB cable short
  • MB992748: V.C.I.-Lite USB cable long
  • MB991223: Wiring harness set
  • MB992006: Extra fine probe
1.Voltage measurement at drive battery connector (control wiring harness connector) (Main contactor forcible shut-off signal line)
(1) Disconnect the connector, and measure at the wiring harness side.
(2) Measure the voltage of the following.
  • Voltage between the drive battery connector (control wiring harness connector) (terminal No. 32) and body ground
OK: Battery voltage
Is the check result normal?
 
2.Check of main contactor forcible shut-off signal line between PHEV-ECU connector and drive battery connector (control wiring harness connector)
Check the following for open circuit.
  • Open circuit between the PHEV-ECU connector (CSDN terminal) and drive battery connector (control wiring harness connector) (terminal No. 32)
Is the check result normal?
Repair the connector(s) or wiring harness.
 
3.Voltage measurement at PHEV-ECU connector (Main contactor forcible shut-off signal voltage)
(1) Measure the PHEV-ECU connector side by backprobing.
(2) Change the power supply mode of the electric motor switch to ON (READY indicator: OFF).
(3) Measure the voltage of the following.
  • Voltage between the PHEV-ECU connector (CSDN terminal) and body ground
OK: 1 V or less
Is the check result normal?
 
4.Check whether the DTC is set again.
(1) Erase the DTC set in the BMU2.
(2) Erase the DTC set in the BMU.
(3) Change the power supply mode of the electric motor switch to ON (READY indicator: ON).
(4) Wait for 10 seconds or more.
(5) Check whether the DTC is set again.
Is the DTC set?
The trouble can be an intermittent malfunction (Refer to General Information - How to Use Troubleshooting/Inspection Service Points, How to Cope with Intermittent Malfunctions HOW TO COPE WITH INTERMITTENT MALFUNCTIONS).
 
5.Drive battery control wiring harness check (Main contactor forcible shut-off signal line)
(1) Disassemble the drive battery (Refer to SERVICE PROCEDURE).
(2) Check the following wiring harness for open circuit.
  • Between the BMU connector (terminal No. 16) and the drive battery connector (control wiring harness connector) (terminal No. 32)
Is the check result normal?
Replace the BMU (Refer to BATTERY MANAGEMENT UNIT (BMU) REMOVAL AND INSTALLATION).
Repair the connector(s) or wiring harness.
 
6.Check whether the DTC is set again.
(1) Erase the DTC set in the BMU2.
(2) Erase the DTC set in the BMU.
(3) Change the power supply mode of the electric motor switch to ON (READY indicator: ON).
(4) Wait for 10 seconds or more.
(5) Check whether the DTC is set again.
Is the DTC set?
Replace the PHEV-ECU (Refer to PHEV-ECU REMOVAL AND INSTALLATION).
The trouble can be an intermittent malfunction (Refer to General Information - How to Use Troubleshooting/Inspection Service Points, How to Cope with Intermittent Malfunctions HOW TO COPE WITH INTERMITTENT MALFUNCTIONS).