SFI SYSTEM MIL Circuit

DESCRIPTION

The MIL (Malfunction Indicator Lamp) is used to indicate vehicle malfunctions detected by the ECM. When the engine switch is turned to on (IG), power is supplied to the MIL circuit, and the ECM provides the circuit ground which illuminates the MIL.

The MIL operation can be checked visually: When the engine switch is turned to on (IG), the MIL should illuminate and should then turn off. If the MIL remains illuminated or does not illuminate, conduct the following troubleshooting procedure using the intelligent tester.

WIRING DIAGRAM

INSPECTION PROCEDURE

PROCEDURE

1. CHECK THAT MIL IS ILLUMINATED

   
   

   1. Turn the engine switch on (IG).

   2. Check the illumination of the MIL.

      Result
      Result Proceed to MIL remains on (Illuminate at all) A MIL remains off (Does not illuminate at all) B MIL illuminates, but turns off after engine is started C

   
   

   B

   CHECK THAT ENGINE STARTS Click here

   C

   SYSTEM OK

   A

2. CHECK WHETHER MIL TURNS OFF

   
   

   1. Connect the intelligent tester to the DLC3.

   2. Turn the engine switch on (IG).

   3. Turn the tester on.

   4. Enter the following menus: Powertrain / Engine / DTC.

   5. Check if any DTCs have been stored. Note down any DTCs.

   6. Clear the DTCs Click here.

   7. Check if the MIL goes off.

      OK
      MIL goes off.

   
   

   NG

   CHECK HARNESS AND CONNECTOR (CHECK FOR SHORT IN WIRE HARNESS) Click here

   OK

   REPAIR CIRCUITS INDICATED BY OUTPUT DTCS Click here

3. CHECK HARNESS AND CONNECTOR (CHECK FOR SHORT IN WIRE HARNESS)

   
   

   1. Disconnect the A70 ECM connector.

   2. Turn the engine switch on (IG).

   3. Check that the MIL is not illuminated.

      OK
      MIL is not illuminated.

   4. Reconnect the ECM connector.

   
   

   NG

   CHECK HARNESS AND CONNECTOR (COMBINATION METER ASSEMBLY - ECM) Click here

   OK

   REPLACE ECM Click here

4. CHECK HARNESS AND CONNECTOR (COMBINATION METER ASSEMBLY - ECM)

   
   

   1. Disconnect the combination meter assembly connector.

   2. Disconnect the ECM connector.

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

      Standard Resistance (Check for Short)
      Tester Connection Condition Specified Condition F16-21 (CHK) or A70-36 (W) - Body ground Always 10 kΩ or higher

   4. Reconnect the combination meter assembly connector.

   5. Reconnect the ECM connector.

   
   

   NG

   REPAIR OR REPLACE HARNESS OR CONNECTOR (COMBINATION METER ASSEMBLY - ECM)

   OK

   REPLACE COMBINATION METER ASSEMBLY Click here

5. CHECK THAT ENGINE STARTS

   
   

   1. Turn the engine switch on (IG).

   2. Start the engine.

      Result
      Result Proceed to Engine starts A Engine does not start* B

      Tech Tips

      *: The intelligent tester cannot communicate with the ECM.

   
   

   B

   GO TO VC OUTPUT CIRCUIT Click here

   A

6. CHECK ECM (W TERMINAL VOLTAGE)

   
   
   1. 

      Text in Illustration

      *a	Front view of wire harness connector (to ECM)

      Disconnect the ECM connector.

   2. Turn the engine switch on (IG).

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

      Standard Voltage
      Tester Connection Condition Specified Condition A70-36 (W) - Body ground Engine switch on (IG) 11 to 14 V

   4. Reconnect the ECM connector.

   
   

   NG

   CHECK HARNESS AND CONNECTOR (COMBINATION METER ASSEMBLY - ECM) Click here

   OK

   REPLACE ECM Click here

7. CHECK HARNESS AND CONNECTOR (COMBINATION METER ASSEMBLY - ECM)

   
   

   1. Disconnect the combination meter assembly connector.

   2. Disconnect the ECM connector.

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

      Standard Resistance (Check for Open)
      Tester Connection Condition Specified Condition F16-21 (CHK) - A70-36 (W) Always Below 1 Ω

   4. Reconnect the ECM connector.

   5. Reconnect the combination meter assembly connector.

   
   

   NG

   REPAIR OR REPLACE HARNESS OR CONNECTOR (COMBINATION METER ASSEMBLY - ECM)

   OK

   REPLACE COMBINATION METER ASSEMBLY Click here