MIL Circuit: Wiring Diagram

Fig 1: MIL Circuit Wiring Diagram

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

HINT:

Troubleshoot each problem symptom in accordance with the chart below.

1. CLEAR DTC 
   1. Connect the intelligent tester to the CAN VIM. Then connect the CAN VIM to the DLC3.
   2. Turn the engine switch on (IG) and turn the tester ON.
   3. Read the DTC.
   4. Clear the DTC.
   5. Check that the MIL is not illuminated.

      OK: 

      MIL is not illuminated. 

   OK : REPAIR CIRCUIT INDICATED BY OUTPUT DTC 

   NG : GO TO NEXT STEP. 

2. CHECK WIRE HARNESS (CHECK FOR SHORT IN WIRE HARNESS) 
   1. Disconnect the A7 ECM connector.
   2. Turn the engine switch on (IG).
   3. Check that the MIL is not illuminated.
      Fig 2: Identifying A7 ECM Connector

      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      OK: 

      MIL is not illuminated. 

   OK : REPLACE ECM 

   NG : GO TO NEXT STEP. 

3. CHECK WIRE HARNESS (COMBINATION METER - ECM) 
   1. Disconnect the K31 combination meter connector.
   2. Disconnect the A7 ECM connector.
   3. Measure the resistance of the wire harness side connectors.

      Standard resistance 

      TESTER CONNECTION AND SPECIFIED CONDITION CHART
      
      

      Tester Connection	Specified Condition
      K31-8 - A7-8 (W)	Below 1 Ω
      K31-8 or A7-8 (W) - Body ground	10 kΩ or higher

   NG : REPAIR OR REPLACE HARNESS AND CONNECTOR 

   OK : REPAIR OR REPLACE COMBINATION METER 

4. CHECK THAT MIL IS ILLUMINATED 
   1. Check that the MIL is illuminated when turning the engine switch on (IG).

      OK: 

      MIL is illuminated. 

   OK : SYSTEM OK 

   NG : GO TO NEXT STEP. 

5. CHECK WIRE HARNESS (COMBINATION METER - BODY GROUND) 
   1. Disconnect the A7 ECM connector.
   2. Turn the engine switch on (IG).
   3. Measure the voltage of the wire harness side connector.
      Fig 3: Measuring Voltage Of Wire Harness Side Connector

      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      Standard voltage 

      TESTER CONNECTION AND SPECIFIED CONDITION CHART
      
      

      Tester Connection	Specified Condition
      A7-8 (W) - Body ground	10 to 14 V

   OK : REPLACE ECM 

   NG : GO TO NEXT STEP. 

6. CHECK WIRE HARNESS (COMBINATION METER - ECM) 
   1. Disconnect the K31 combination meter connector.
   2. Disconnect the A7 ECM connector.
   3. Measure the resistance of the wire harness side connectors.

      Standard resistance 

      TESTER CONNECTION AND SPECIFIED CONDITION CHART
      
      

      Tester Connection	Specified Condition
      K31-8 - A7-8 (W)	Below 1 Ω
      K31-8 or A7-8 (W) - Body ground	10 kΩ or higher

   NG : REPAIR OR REPLACE HARNESS AND CONNECTOR 

   OK : REPAIR OR REPLACE COMBINATION METER