MIL Circuit

1GR-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 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 the Techstream.

WIRING DIAGRAM





INSPECTION PROCEDURE

PROCEDURE

1. CHECK THAT MIL IS ILLUMINATED
(a) Perform troubleshooting in accordance with the chart below.

Result





B -- CHECK THAT MIL IS ILLUMINATED
A -- Continue to next step.

2. CHECK WHETHER MIL TURNS OFF
(a) Connect the Techstream to the DLC3.
(b) Turn the ignition switch to ON.
(c) Turn the Techstream 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.
NG -- CHECK HARNESS AND CONNECTOR (CHECK FOR SHORT IN WIRE HARNESS)
OK -- REPAIR CIRCUIT INDICATED BY OUTPUT DTC
3. CHECK HARNESS AND CONNECTOR (CHECK FOR SHORT IN WIRE HARNESS)




(a) Disconnect the ECM connector.
(b) Turn the ignition switch to ON.
(c) Check that MIL is not illuminated.
OK:
MIL is not illuminated.
(d) Reconnect the ECM connector.
NG -- CHECK AND REPAIR HARNESS OR CONNECTOR (COMBINATION METER - ECM)
OK -- REPLACE ECM
4. CHECK THAT MIL IS ILLUMINATED
(a) Check if the MIL is illuminated when the ignition switch is turns ON.
OK:
MIL should be illuminated.
NG -- CHECK THAT ENGINE STARTS
OK -- END
5. CHECK THAT ENGINE STARTS
(a) Turn the ignition switch to ON.
(b) Start the engine.

Result





HINT: *: The Techstream cannot communicate with the ECM.

B -- GO TO VC OUTPUT CIRCUIT
A -- Continue to next step.

6. INSPECT COMBINATION METER ASSEMBLY (MIL CIRCUIT)
(a) See the combination meter troubleshooting procedure Installation.
NG -- REPAIR OR REPLACE BULB OR COMBINATION METER ASSEMBLY
OK -- CHECK AND REPAIR HARNESS OR CONNECTOR (COMBINATION METER - ECM)