Last Modified: 7-3-2017 6.8:8.0.40 Doc ID: RM000000TMT00WX
Model Year Start: 2007 Model: LX470 Prod Date Range: [08/2006 -           ]
Title: 2UZ-FE ENGINE CONTROL SYSTEM: SFI SYSTEM: MIL Circuit; 2007 MY LX470 [08/2006 -        ]

MIL Circuit

DESCRIPTION

The Malfunction Indicator Lamp (MIL) is used to indicate the ECM's detection of a vehicle malfunction.

The instrument panel MET fuse provides the circuit with power and the ECM provides the circuit ground that illuminates the MIL.

MIL operations should be checked visually:

The MIL should be illuminated when the ignition switch is turned ON. If the MIL is always ON or OFF, use the intelligent tester and follow the procedures below to determine the cause of the problem.

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 MILL IS ILLUMINATED

(a) Perform troubleshooting in accordance with the chart below.

Condition

Proceed to

MIL remains ON

A

MIL does not illuminate

B
B

GO TO STEP 5

A

2.

CHECK WHETHER MIL TURNS OFF

(a) Connect the intelligent tester to the CAN VIM. Then connect the CAN VIM to the DLC3.

(b) Turn the ignition switch ON and turn the intelligent tester ON.

(c) Check whether any DTCs have been stored 2007 MY LX470 [08/2006 -        ]; 2UZ-FE ENGINE CONTROL SYSTEM: SFI SYSTEM: DTC CHECK / CLEAR . Note them down if necessary.

(d) Clear the DTC 2007 MY LX470 [08/2006 -        ]; 2UZ-FE ENGINE CONTROL SYSTEM: SFI SYSTEM: DTC CHECK / CLEAR .

(e) Check if the MIL turns off.

OK:

MIL should turn off.

OK

REPAIR CIRCUIT INDICATED BY OUTPUT DTC

NG

3.

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

(a) Disconnect the E9 ECM connector.

(b) Turn the ignition switch ON.

(c) Check that the MIL is not illuminated.

OK:

MIL is not illuminated.
OK

REPLACE ECM

NG

4.

CHECK HARNESS AND CONNECTOR (COMBINATION METER - ECM)

(a) Check harness and connector 2007 MY LX470 [08/2006 -        ]; INTRODUCTION: HOW TO TROUBLESHOOT ECU CONTROLLED SYSTEMS: ELECTRONIC CIRCUIT INSPECTION PROCEDURE .

OK

REPAIR OR REPLACE COMBINATION METER

NG

REPAIR OR REPLACE HARNESS AND CONNECTOR

5.

CHECK THAT MIL IS ILLUMINATED

(a) Check that the MIL is illuminated when turning the ignition switch ON.

OK:

MIL is illuminated.

OK

SYSTEM OK

NG

6.

CHECK THAT ENGINE STARTS

(a) Turn the ignition switch ON.

(b) Start the engine.

Result

Proceed to

Engine starts

A

Engine does not start*

B

HINT:

*: The intelligent tester cannot communicate with the ECM.

B

GO TO VC OUTPUT CIRCUIT

A

7.

INSPECT COMBINATION METER (MIL CIRCUIT)

(a) See the combination meter troubleshooting section 2007 MY LX470 [08/2006 -        ]; METER: METER / GAUGE SYSTEM: HOW TO PROCEED WITH TROUBLESHOOTING .

NG

REPAIR OR REPLACE COMBINATION METER

OK

CHECK AND REPLACE HARNESS OR CONNECTOR (COMBINATION METER - ECM)