Ecd System - Mil Circuit

Lexus IS250 IS220d GSE20 ALE20 2AD-FHV ENGINE CONTROL SYSTEM

DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

CHECK MIL CONDITION (WHETHER MIL TURNS OFF)

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

CHECK HARNESS AND CONNECTOR (COMBINATION METER - ECM)

CHECK MIL CONDITION (MIL IS ILLUMINATED)

CHECK HARNESS AND CONNECTOR

CHECK HARNESS AND CONNECTOR (COMBINATION METER - ECM)

ECD SYSTEM - MIL Circuit

DESCRIPTION

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


By turning the engine switch 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 first turned on (IG), the MIL should be illuminated and should then go off. If the MIL remains illuminated or is not illuminated, conduct the following troubleshooting procedure using the intelligent tester.


WIRING DIAGRAM

Ecd System - Mil Circuit. 2AD-FHV ENGINE CONTROL SYSTEM. Lexus IS250 IS220d GSE20 ALE20

INSPECTION PROCEDURE

  • HINT:
  • Troubleshoot each trouble symptom in accordance with the chart below.
MIL remains illuminatedStart inspection from step 1
MIL not illuminatedStart inspection from step 3
1.CHECK MIL CONDITION (WHETHER MIL TURNS OFF)

Connect the intelligent tester to the DLC3.

Turn the engine switch ON (IG).

Turn the tester ON.

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

Clear DTCs .

Check if the MIL turns off.

  • OK:
  • MIL should turn off.
OK
REPAIR CIRCUITS INDICATED BY OUTPUT DTCS
NG
2.CHECK HARNESS AND CONNECTOR (CHECK FOR SHORT IN WIRE HARNESS)

Disconnect the A49 ECM connector.

Turn the engine switch on (IG).

Check the MIL is not illuminated.

  • OK:
  • MIL is not illuminated.

Reconnect the ECM connector.

OK
REPLACE ECM
NG
3.CHECK HARNESS AND CONNECTOR (COMBINATION METER - ECM)
Ecd System - Mil Circuit. 2AD-FHV ENGINE CONTROL SYSTEM. Lexus IS250 IS220d GSE20 ALE20

Disconnect the A49 ECM connector.

Disconnect the J35 combination meter connector.

Measure the resistance of the wire harness side connector.

  • Standard resistance (Check for open):
  • Tester ConnectionSpecified Condition
    W (A49-12) - EFI (J35-12)Below 1 Ω
  • Standard resistance (Check for short):
  • Tester ConnectionSpecified Condition
    W (A49-12) or EFI (J35-12) - Body ground10 kΩ or higher
OK
REPAIR OR REPLACE COMBINATION METER ASSEMBLY
NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
4.CHECK MIL CONDITION (MIL IS ILLUMINATED)

Check if the MIL is illuminated when the engine switch is turns on (IG).

  • OK:
  • MIL should be illuminated.
OK
SYSTEM IS OK
NG
5.CHECK HARNESS AND CONNECTOR
Ecd System - Mil Circuit. 2AD-FHV ENGINE CONTROL SYSTEM. Lexus IS250 IS220d GSE20 ALE20

Disconnect the A49 ECM connector.

Turn the engine switch on (IG).

Measure the voltage of the wire harness side connector.

  • Standard voltage:
  • Tester ConnectionSpecified Condition
    W (A49-12) - Body ground10 to 14 V

Reconnect the ECM connector.

OK
REPLACE ECM
NG
6.CHECK HARNESS AND CONNECTOR (COMBINATION METER - ECM)
Ecd System - Mil Circuit. 2AD-FHV ENGINE CONTROL SYSTEM. Lexus IS250 IS220d GSE20 ALE20

Disconnect the A49 ECM connector.

Disconnect the J35 combination meter connector.

Measure the resistance of the wire harness side connector.

  • Standard resistance (Check for open):
  • Tester ConnectionSpecified Condition
    W (A49-12) - EFI (J35-12)Below 1 Ω
  • Standard resistance (Check for short):
  • Tester ConnectionSpecified Condition
    W (A49-12) or EFI (J35-12) - Body ground10 kΩ or higher
OK
REPAIR OR REPLACE COMBINATION METER ASSEMBLY
NG
REPAIR OR REPLACE HARNESS OR CONNECTOR