Engine Switch Indicator Circuit: Procedure

1. Remove the engine switch. Refer to REMOVAL .
   Fig 1: Identifying Engine Switch Connector Terminals

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Apply battery voltage to the switch and check the illumination condition of the engine switch indicator light.
   NOTE:

   • If the positive (+) lead and the negative (-) lead are incorrectly connected, the engine switch indicator light does not illuminate.
   • If the voltage is too low, the indicator light does not illuminate.

   OK

   Measurement Condition	Condition	Specified Condition
   Battery terminal (+) → Terminal 11 (SWIL) Battery terminal (-) → Terminal 4 (COM) or 5 (GND)	Battery voltage is applied to the terminals	Illuminates
   Battery terminal (+) → Terminal 12 (INDS) Battery terminal (-) → Terminal 4 (COM) or 5 (GND)	Battery voltage is applied to the terminals	Illuminates (green)
   Battery terminal (+) → Terminal 13 (INDW) Battery terminal (-) → Terminal 4 (COM) or 5 (GND)	Battery voltage is applied to the terminals	Illuminates (amber)

NG → See step   3 

OK: Go to next step 

Fig 2: Identifying Engine Switch And Main Body ECU Connector Terminals

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

1. Disconnect the E78 engine switch connector.
2. Disconnect the E16 and E17 main body ECU connectors.
3. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   E78-11 (SWIL) - E16-8 (SWIL)	Always	Below 1 Ω
   E78-12 (INDS) - E17-1 (INDS)	Always	Below 1 Ω
   E78-13 (INDW) - E17-8 (INDW)	Always	Below 1 Ω
   E78-5 (GND) - Body ground	Always	Below 1 Ω
   E78-4 (COM) - Body ground	Always	Below 1 Ω
   E78-11 (SWIL) or E16-8 (SWIL) - Body ground	Always	10 kΩ or higher
   E78-12 (INDS) or E17-1 (INDS) - Body ground	Always	10 kΩ or higher
   E78-13 (INDW) or E17-8 (INDW) - Body ground	Always	10 kΩ or higher

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK → REPLACE MAIN BODY ECU (INSTRUMENT PANEL JUNCTION BLOCK)