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DTC No. P1A56-12 IGCT relay Control Circuit High
 
 
 
 
DTC SET CONDITION
Check Condition
  • The IGCT power supply is ON.
Judgment Criterion
  • The failure of the IGCT control relay operation circuit is detected for 2 seconds or more.
 
 
TROUBLESHOOTING HINTS
  • Damaged wiring harness and connectors
  • Malfunction of the IGCT control relay
  • Malfunction of the PHEV-ECU
 
 
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.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.
 
2.Voltage measurement at IGCT control relay connector (excitation side downstream 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 connector (excitation side downstream terminal) and body ground.
OK: 1 V or less
Is the check result normal?
Repair the connector(s) or wiring harness in CTLM line between the IGCT control relay connector (excitation side downstream terminal) and PHEV-ECU connector.
 
3.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).