ECD SYSTEM (w/o DPF) MIL Circuit

DESCRIPTION

The MIL (Malfunction Indicator Lamp) is used to indicate vehicle malfunction detections by the ECM.

By turning the ignition switch to ON, 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 ignition switch is first turned ON, the MIL should be illuminated and should then turn OFF. If the MIL remains illuminated or is not illuminated, conduct the following troubleshooting procedure using an intelligent tester.

WIRING DIAGRAM

INSPECTION PROCEDURE

PROCEDURE

1. CHECK THAT MIL IS ILLUMINATED

   
   

   1. Perform troubleshooting in accordance with the chart below.

      Result
      MIL Condition Proceed To MIL remains ON A MIL does not illuminate B

   
   

   B

   CHECK THAT MIL IS ILLUMINATED Click here

   A

2. CHECK WHETHER MIL TURNS OFF

   
   

   1. Connect an intelligent tester to the DLC3.

   2. Turn the ignition switch to ON and turn the tester ON.

   3. Select the following menu items: Powertrain / Engine / DTC.

   4. Check whether any DTCs have been stored Click here. Note them down if necessary.

   5. Select the following menu items: Powertrain / Engine / DTC / Clear.

   6. Clear DTCs.

   7. Check if the MIL turns off.

      OK
      MIL should turn off.

   
   

   OK

   REPAIR CIRCUITS INDICATED BY OUTPUT DTCS

   NG

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

   

   
   

   1. Disconnect the B9 ECM connector.

   2. Turn the ignition switch to ON.

   3. Check that MIL is not illuminated.

      OK
      MIL is not illuminated.

   4. Reconnect the ECM connector.

   
   

   OK

   REPLACE ECM

   NG

   CHECK AND REPAIR HARNESS OR CONNECTOR (COMBINATION METER - ECM)

4. CHECK THAT MIL IS ILLUMINATED

   
   

   1. Check if the MIL is illuminated when the ignition switch is turned to ON.

      OK
      MIL should be illuminated.

   
   

   OK

   SYSTEM OK

   NG

5. CHECK THAT ENGINE STARTS

   
   

   1. Turn the ignition switch to ON.

   2. Start the engine.

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

      Tech Tips

      *: An intelligent tester cannot communicate with the ECM.

   
   

   B

   GO TO VC OUTPUT CIRCUIT

   A

6. INSPECT COMBINATION METER ASSEMBLY (MIL CIRCUIT)

   
   

   1. See the combination meter troubleshooting procedure Click here.

   
   

   NG

   REPAIR OR REPLACE BULB OR COMBINATION METER ASSEMBLY

   OK

   CHECK AND REPAIR HARNESS OR CONNECTOR (COMBINATION METER - ECM)