Malfunction Indicator Lamp: Testing and Inspection

2AZ-FXE 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 (included in hybrid vehicle control ECU). When the power 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 power 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 using the Techstream.

WIRING DIAGRAM





INSPECTION PROCEDURE

PROCEDURE

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






B -- CHECK MIL CONDITION (MIL ILLUMINATED)
A -- Continue to next step.
2. CHECK MIL CONDITION (WHETHER MIL TURNS OFF)
(a) Connect the Techstream to the DLC3.
(b) Turn the power switch on (IG) and turn the tester on.
(c) Select the following menu items: Powertrain / Engine / Trouble Code.
(d) Check if any DTCs have been stored. Note down any DTCs.
(e) Clear the DTCs DTC Check / Clear.
(f) Check if the MIL goes off.
Standard:
MIL should go off.
OK -- REPAIR CIRCUITS INDICATED BY OUTPUT DTCS
NG -- Continue to next step.
3. CHECK HARNESS AND CONNECTOR (CHECK FOR SHORT IN WIRE HARNESS)




(a) Disconnect the A61 hybrid vehicle control ECU connector.
(b) Turn the power switch on (IG).
(c) Check that the MIL is not illuminated.
OK:
MIL is not illuminated.
(d) Reconnect the hybrid vehicle control ECU connector.
OK -- REPLACE HYBRID VEHICLE CONTROL ECU
NG -- Continue to next step.
4. CHECK HARNESS AND CONNECTOR (COMBINATION METER - HYBRID VEHICLE CONTROL ECU)




(a) Disconnect the A61 hybrid vehicle control ECU connector.
(b) Disconnect the F2 combination meter connector.
(c) Measure the resistance.
Standard resistance (Check for short):





(d) Reconnect the hybrid vehicle control ECU connector.
(e) Reconnect the combination meter connector.
OK -- REPAIR OR REPLACE COMBINATION METER ASSEMBLY
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
5. CHECK MIL CONDITION (MIL ILLUMINATED)
(a) Check if the MIL is illuminated when the power switch is turned on (IG).
OK:
MIL should be illuminated.
OK -- SYSTEM IS OK
NG -- Continue to next step.
6. CHECK THAT ENGINE START
(a) Turn the power switch on (IG).
(b) Put the engine in inspection mode Component Tests and General Diagnostics.
Result:





HINT: *: The Techstream cannot communicate with the hybrid vehicle control ECU.

B -- GO TO VC OUTPUT CIRCUIT
A -- Continue to next step.
7. INSPECT COMBINATION METER ASSEMBLY (MIL CIRCUIT)
(a) Check the MIL circuit Problem Symptoms Table.
NG -- REPAIR OR REPLACE COMBINATION METER ASSEMBLY
OK -- CHECK AND REPLACE HARNESS OR CONNECTOR (COMBINATION METER - HYBRID VEHICLE CONTROL ECU)