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Inspection Procedure 1: PHEV-ECU power supply system malfunction (Cannot communicate with the PHEV-ECU using M.U.T.-IIISE)
 
 
 
 
COMMENTS ON TROUBLE SYMPTOM
The power supply or ground circuit of the PHEV-ECU, or the PHEV-ECU itself is suspected.
 
 
TROUBLESHOOTING HINTS
  • Malfunction of the power supply circuit (faulty connector, faulty relay, blown fuse)
  • Damaged wiring harness and connectors
  • Malfunction of the PHEV-ECU
 
 
DIAGNOSIS
Required Special Tools:
  • MB991223: Wiring harness set
  • MB992006: Extra fine probe
1.Voltage measurement at PHEV-ECU connector (IGCT terminal, IGCT2 terminal)
(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 between the following terminals.
  • Voltage between the PHEV-ECU connector (IGCT terminal) and body ground
  • Voltage between the PHEV-ECU connector (IGC2 terminal) and body ground
OK: Battery voltage
Is the check result normal?
 
2.EV control relay check
Check the EV control relay (Refer to EV CONTROL RELAY CONTINUITY CHECK).
Is the check result normal?
Replace the EV control relay.
 
3.Check of continuity at EV control relay connector (excitation side downstream terminal)
(1) Remove the EV control relay, and measure at the relay box side.
(2) Check the continuity between the EV control relay connector (excitation side downstream terminal) and body ground.
OK: Continuity exists (2 Ω or less)
Is the check result normal?
Repair the connector(s) or wiring harness in ground line between the EV control relay connector (excitation side downstream terminal) and body ground.
 
4.Voltage measurement at EV control relay connector (contact side upstream terminal)
(1) Remove the EV control relay, and measure at the relay box side.
(2) Measure the voltage between the EV control relay connector (contact side upstream terminal) and body ground.
OK: Battery voltage
Is the check result normal?
Repair the faulty part.
 
5.Check of open circuit in IGCT and IGC2 lines between PHEV-ECU and relay box (EV control relay)
Is the check result normal?
Repair the connector(s) or wiring harness.
 
6.Check of short to ground circuit and open circuit in CTL line between PHEV-ECU and relay box (EV control relay)
Is the check result normal?
Repair the connector(s) or wiring harness.
 
7.Check of continuity at PHEV-ECU connector (GND1 terminal, GND2 terminal)
(1) Disconnect the PHEV-ECU connector (E437, E438), and measure at the wiring harness side.
(2) Check the continuity between the following terminals.
  • Continuity between the PHEV-ECU connector (GND1 terminal) and body ground
  • Continuity between the PHEV-ECU connector (GND2 terminal) and body ground
OK: Continuity exists (2 Ω or less)
Is the check result normal?
Repair the connector(s) or wiring harness in GND1 or GND2 line between the PHEV-ECU and body ground.
 
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).