Engine Switch Indicator Circuit: Procedure

1. Disconnect the D21 switch connector.
   Fig 1: Identifying D21 Switch Connector Terminals

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Connect the positive (+) lead to terminal "A" and the negative (-) lead to terminal "B" of the engine switch.
3. Check if the illumination for the engine switch comes on.

   OK

   Positive (+) Connection (Symbols)	Negative (-) Connection (Symbols)	Illumination Condition
   D21-11 (SWIL)	D21-4 (COM) or D21-5 (GND)	Comes on
   D21-12 (INDS)	D21-4 (COM) or D21-5 (GND)	Comes on
   D21-13 (INDW)	D21-4 (COM) or D21-5 (GND)	Comes on

NG → REPLACE ENGINE SWITCH 

OK: Go to next step 

1. Disconnect the D44 ECU connector.
   Fig 2: View Of Disconnected D44 ECU Connector Terminals

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Measure the resistance according to the value(s) in the table below.
   Fig 3: Identifying D21 Switch Connector Terminals

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   Resistance

   Tester Connection (Symbols)	Condition	Specified condition
   D44-4 (INDS) - D21-12 (INDS)	Always	Below 1 Ω
   D44-13 (INDW) - D21-13 (INDW)	Always	Below 1 Ω
   D44-36 (SWIL) - D21-11 (SWIL)	Always	Below 1 Ω
   D44-4 (INDS) - Body ground	Always	1 MΩ or Higher
   D44-13 (INDW) - Body ground	Always	1 MΩ or Higher
   D44-36 (SWIL) - Body ground	Always	1 MΩ or Higher

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK → REPLACE POWER SOURCE CONTROL ECU