MIL Circuit

1ZZ-FE ENGINE CONTROL SYSTEM: SFI SYSTEM: MIL Circuit

MIL Circuit

DESCRIPTION

The MIL (Malfunction Indicator Lamp) is used to indicate vehicle malfunction detections by the ECM.
By turning the ignition switch to the ON position, 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 to the ON position, 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 Techstream.

WIRING DIAGRAM





INSPECTION PROCEDURE

HINT: Troubleshoot each trouble symptom in accordance with the table below.





PROCEDURE

1. CHECK MIL CONDITION (WHETHER MIL TURNS OFF)
(a) Connect Techstream to the DLC3.
(b) Turn the ignition switch to the ON position.
(c) Turn the tester on.
(d) Check whether any DTCs have been stored (DTC Check / Clear). Note them down if necessary.
(e) Clear DTCs (DTC Check / Clear).
(f) Check if the MIL turns off.
OK:
MIL should turn off.
OK -- REPAIR CIRCUITS INDICATED BY OUTPUT DTCS
NG -- Continue to next step.
2. CHECK HARNESS AND CONNECTOR (CHECK FOR SHORT IN WIRE HARNESS)





(a) Disconnect the E6 ECM connector.
(b) Turn the ignition switch to the ON position.
(c) Check that the MIL is not illuminated.
OK:
MIL is not illuminated
(d) Reconnect the ECM connector.
OK -- REPLACE ECM
NG -- CHECK AND REPLACE HARNESS AND CONNECTOR (COMBINATION METER - ECM)
3. CHECK MIL (MIL IS ILLUMINATED)
(a) Check if the MIL is illuminated when the ignition switch is turned to ON.
OK:
MIL should be illuminated.
OK -- SYSTEM IS OK
NG -- Continue to next step.
4. INSPECT COMBINATION METER ASSEMBLY (MIL CIRCUIT)
(a) See the combination meter troubleshooting procedure (Initial Inspection and Diagnostic Overview).
NG -- CHECK AND REPAIR COMBINATION METER ASSEMBLY
OK -- CHECK AND REPAIR HARNESS AND CONNECTOR (COMBINATION METER - ECM)