MIL Circuit

1UR-FSE 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 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 turn off. If the MIL remains illuminated or is not illuminated, conduct the following troubleshooting procedure.

If the ECM detects trouble, the MIL illuminates. At this time, the ECM records a DTC in the memory.

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 IF MIL TURNS OFF

(a) Connect the Techstream to the DLC3.

(b) Turn the engine switch on (IG) and turn the Techstream on.

(c) Check if DTCs have been stored Reading and Clearing Diagnostic Trouble Codes. If DTCs are present, write them down.

(d) Clear the DTCs Reading and Clearing Diagnostic Trouble Codes.

(e) Check that the MIL turns off.

OK:

MIL turns off.

OK -- REPAIR CIRCUITS INDICATED BY OUTPUT DTCS SFI System
NG -- Continue to next step.

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





(a) Disconnect the A14 ECM connector.

(b) Turn the engine switch on (IG).

(c) Check that the MIL is not illuminated.

OK:

MIL is not illuminated.

OK -- REPLACE ECM Removal
NG -- Continue to next step.

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





(a) Disconnect the L10 combination meter connector.

(b) Disconnect the A14 ECM connector.

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

Standard resistance (check for open):





Standard resistance (check for short):





NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR

OK -- REPAIR OR REPLACE COMBINATION METER Removal

5. CHECK THAT MIL IS ILLUMINATED

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

OK:

MIL is illuminated.

OK -- SYSTEM OK
NG -- Continue to next step.

6. CHECK THAT ENGINE STARTS

(a) Turn the engine switch on (IG).

(b) Start the engine.

Result:





HINT
*: The Techstream cannot communicate with the ECM.

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

7. INSPECT COMBINATION METER ASSEMBLY (MIL CIRCUIT)

(a) See the combination meter troubleshooting procedure How To Proceed With Troubleshooting.

NG -- REPAIR OR REPLACE COMBINATION METER ASSEMBLY Removal

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