MIL Circuit 2ZR-FXE

MIL Circuit

Description

Wiring diagram

Inspection procedure

Check that mil is illuminated

Check whether mil turns off

Check harness and connector (check for short in wire harness)

Check harness and connector (combination meter assembly - ecm)

Check that engine starts

Check harness and connector (ecm terminal voltage)

Check harness and connector (combination meter assembly - ecm)

Description

The MIL (Malfunction Indicator Lamp) is used to indicate vehicle malfunction detected by the ECM. When the power switch is turned 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 power switch is first turned on (IG), the MIL should illuminate and should then turn off. If the MIL remains illuminated or is not illuminated, conduct the following troubleshooting procedure using the intelligent tester.

Wiring diagram

Lexus MIL Circuit. Wiring diagram.

Inspection procedure

1.CHECK THAT MIL IS ILLUMINATED

  1. Turn the power switch on (IG).

  1. Check the illumination of the MIL.

    Result
    Condition Proceed to
    MIL remains illuminated (Even after power switch is turned on (IG) and several seconds have passed, MIL still remains illuminated) A
    MIL remains off (Does not illuminate at all) B
    MIL illuminates for several seconds, but turns off after engine is started C
  B  
Go to step 5
 
  C  
SYSTEM OK
 
OK  
   

2.CHECK WHETHER MIL TURNS OFF

  1. Connect the intelligent tester to the DLC3.

  1. Turn the power switch on (IG).

  1. Turn the tester on.

  1. Enter the following menus: Powertrain / Engine and ECT / DTC.

  1. Check if any DTCs have been stored. Note down the DTCs.

  1. Clear the DTCs .

  1. Check if the MIL goes off.

    OK:

    MIL goes off.

  NG  
Go to step 3
 
OK  
   
REPAIR CIRCUITS INDICATED BY OUTPUT DTCS

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

  1. Disconnect the A60 ECM connector.

  1. Turn the power switch on (IG).

  1. Check that the MIL is not illuminated.

    OK:

    MIL is not illuminated.

  NG  
Go to step 4
 
OK  
   
REPLACE ECM

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

  1. Disconnect the combination meter assembly connector.

  1. Disconnect the ECM connector.

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

    Standard Resistance:

    Tester Connection Condition Specified Condition
    H19-28 (EFI) or A60-36 (W) - Body ground Always 10 k? or higher
  NG  
REPAIR OR REPLACE HARNESS OR CONNECTOR
 
OK  
   
REPLACE COMBINATION METER ASSEMBLY

5.CHECK THAT ENGINE STARTS

  1. Turn the power switch on (IG).

  1. Put the engine in inspection mode (maintenance mode) .

  1. Start the engine.

    Result
    Result Proceed to
    Engine starts A
    Engine cannot be put in inspection mode* (Engine cannot start) B

    HINT:

    *: The intelligent tester cannot communicate with the ECM.

  B  
GO TO VC OUTPUT CIRCUIT
 
OK  
   

6.CHECK HARNESS AND CONNECTOR (ECM TERMINAL VOLTAGE)

  1. Disconnect the ECM connector.

  1. Turn the power switch on (IG).

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

    Standard Voltage:

    Tester Connection Switch Condition Specified Condition
    A60-36 (W) - Body ground Power switch on (IG) 11 to 14 V
  NG  
Go to step 7
 
OK  
   
REPLACE ECM

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

  1. Disconnect the combination meter assembly connector.

  1. Disconnect the ECM connector.

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

    Standard Resistance:

    Tester Connection Condition Specified Condition
    H19-28 (EFI) - A60-36 (W) Always Below 1 ?
  NG  
REPAIR OR REPLACE HARNESS OR CONNECTOR
 
OK  
   
REPLACE COMBINATION METER ASSEMBLY