DTC P18A8-62: Gear Shift Control Module "A"/"B" IGCT-Scene Signal Compare Failure [03/2023 - ]: Procedure

Pre-procedure1

• Disconnect the C49 shift actuator ECU (shift control actuator assembly) connector.
• Connect the cable to the negative (-) auxiliary battery terminal.
• Turn the ignition switch to ON.

• Measure the voltage according to the value(s) in the table below.

  Standard Voltage

  Tester Connection	Switch Condition	Specified Condition	Result
  C49-5 (IGC1) - Body ground	Ignition switch ON	11 to 14 V	V

  Result

  Proceed to
  OK
  NG

Post-procedure1

• Turn the ignition switch off.
• Disconnect the cable from the negative (-) auxiliary battery terminal.
• Reconnect the shift actuator ECU (shift control actuator assembly) connector.

Result: 

OK 

REPLACE SHIFT CONTROL ACTUATOR ASSEMBLY (SHIFT ACTUATOR ECU) 

Refer to REMOVAL [12/2022 - ]

Result: 

NG 

See step  2

Pre-procedure1

• Remove the IGCT SCENE relay from the No. 3 relay block.

• Measure the resistance according to the value(s) in the table below.

  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

  *1	IGCT SCENE Relay

  Standard Resistance

  Tester Connection	Condition	Specified Condition	Result
  3 - 5	Auxiliary battery voltage not applied between terminals 1 and 2	10 kΩ or higher	kΩ
  3 - 5	Auxiliary battery voltage applied between terminals 1 and 2	Below 1 Ω	Ω

  Result

  Proceed to
  OK
  NG

Post-procedure1

• Install the IGCT SCENE relay.

Result: 

OK 

REPAIR OR REPLACE HARNESS OR CONNECTOR (IGC1 POWER SUPPLY CIRCUIT) 

Result: 

NG 

REPLACE IGCT SCENE RELAY