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Inspection Procedure 1: DC-DC converter power supply system malfunction (Cannot communicate with the DC-DC converter using M.U.T.-IIISE.)
 
 
 
 
COMMENTS ON TROUBLE SYMPTOM
The power supply circuit of the On Board Charger (OBC)/DC-DC converter, the On Board Charger (OBC)/DC-DC converter itself or the PHEV-ECU is suspected.
 
 
TROUBLESHOOTING HINTS
  • Malfunction of the On Board Charger (OBC)/DC-DC converter power supply circuit
  • Damaged wiring harness and connectors
  • Malfunction of the PHEV-ECU
  • Malfunction of the On Board Charger (OBC)/DC-DC converter
 
 
DIAGNOSIS
Required Special Tools:
  • MB991223: Wiring harness set
  • MB992006: Extra fine probe
1.Voltage measurement at the On Board Charger (OBC)/DC-DC converter connector (IGCT power supply line)
(1) Disconnect the On Board Charger (OBC)/DC-DC converter connector (B531), and measure at the wiring harness side.
(2) Change the power supply mode of the electric motor switch to ON (READY indicator: OFF).
(3) Measure the voltage between the following terminals.
  • Voltage between the On Board Charger (OBC)/DC-DC converter connector (No. 7 terminal) and body ground
OK: Battery voltage
Is the check result normal?
 
2.IGCT control relay check
Check the IGCT control relay (Refer to IGCT CONTROL RELAY CONTINUITY CHECK) .
Is the check result normal?
Replace the IGCT control relay.
 
3.Voltage measurement at the IGCT control relay (contact side upstream terminal)
(1) Remove the IGCT control relay, and measure at the fuse block side.
(2) Measure the voltage between the IGCT control relay (contact side upstream terminal) and body ground
OK: Battery voltage
Is the check result normal?
Repair the faulty part.
 
4.Voltage measurement at the IGCT control relay (excitation side upstream terminal)
(1) Remove the IGCT control relay, and measure at the fuse block side.
(2) Change the power supply mode of the electric motor switch to ON (READY indicator: OFF).
(3) Measure the voltage between the IGCT control relay (excitation side upstream terminal) and body ground.
OK: Battery voltage
Is the check result normal?
 
5.Check of short to ground circuit and open circuit in CTL line between the PHEV-ECU and fuse block (IGCT control relay)
Is the check result normal?
Repair the connector(s) or wiring harness.
 
6.Check of open circuit in CTLM line between the PHEV-ECU and fuse block (IGCT control relay)
Is the check result normal?
Repair the connector(s) or wiring harness.
 
7.Check of open circuit in IGCT line between the On Board Charger (OBC)/DC-DC converter and fuse block (IGCT control relay)
Check the following wiring harness for open circuit.
  • Open circuit between the On Board Charger (OBC)/DC-DC converter connector (No. 7 terminal) and fuse block (IGCT control relay)
Is the check result normal?
Repair the connector(s) or wiring harness.
 
8.Retest the system.
Does the trouble symptom persist?
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).
 
9.Check of open circuit in ground line between the On Board Charger (OBC)/DC-DC converter and body ground
Check the following wiring harness for open circuit.
  • Open circuit between the On Board Charger (OBC)/DC-DC converter connector (No. 2 terminal) and body ground
Is the check result normal?
Repair the connector(s) or wiring harness.
 
10.Retest the system.
Does the trouble symptom persist?
Repalce the On Board Charger (OBC)/DC-DC converter (Refer to ON BOARD CHARGER (OBC) &DC-DC CONVERTER 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).