Last Modified: 04-05-2023 6.11:8.1.0 Doc ID: RM1000000019SSC
Model Year Start: 2018 Model: Sienna Prod Date Range: [11/2017 -           ]
Title: 2GR-FKS (ENGINE CONTROL): SFI SYSTEM: MIL Circuit; 2018 - 2020 MY Sienna [11/2017 -        ]

MIL Circuit

DESCRIPTION

The Malfunction Indicator Lamp (MIL) is used to indicate vehicle malfunctions detected 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 illuminate and should then turn off. If the MIL remains illuminated or does not illuminate, conduct the following troubleshooting procedure. If the ECM detects any trouble, the MIL illuminates. At this time, the ECM records a DTC in the memory.

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

Check the fuses for circuits related to this system before performing the following inspection procedure.

PROCEDURE

1.

CHECK THAT MIL ILLUMINATES

(a) Turn the ignition switch to ON.

(b) Check the illumination of the MIL.

Result

Proceed to

MIL remains illuminated (Even after ignition switch is turned ON and several seconds have passed, MIL still remains illuminated)

A

MIL remains off (Does not illuminate at all)

B
B

GO TO STEP 5

A

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) Enter the following menus: Powertrain / Engine / Trouble Codes.

(e) Check if any DTCs have been stored. Note any DTCs.

(f) Clear the DTCs.

(g) Check if the MIL goes off.

Result

Proceed to

MIL goes off

A

MIL does not go off

B
A

REPAIR CIRCUIT INDICATED BY OUTPUT DTC
B

3.

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

(a) Disconnect the ECM connector.

*a

Front view of wire harness connector

(to ECM)

(b) Turn the ignition switch to ON.

(c) Check if the MIL is illuminated.

Result

Proceed to

MIL is not illuminated

A

MIL is illuminated

B
A

REPLACE ECM

B

4.

CHECK HARNESS AND CONNECTOR (COMBINATION METER ASSEMBLY - ECM)

(a) Disconnect the D146 combination meter assembly connector.

(b) Disconnect the A69 ECM connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

D146-12 (CHK) or A69-29 (W) - Body ground

Always

10 kΩ or higher
OK

REPLACE COMBINATION METER ASSEMBLY

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

5.

CHECK IF ENGINE STARTS

(a) Start the engine.

Result

Proceed to

Engine starts

A

Engine does not start*

B

HINT:

*: The Techstream cannot communicate with the ECM.

B

GO TO VC OUTPUT CIRCUIT

A

6.

CHECK HARNESS AND CONNECTOR (ECM TERMINAL VOLTAGE)

(a) Disconnect the ECM connector.

*a

Front view of wire harness connector

(to ECM)

(b) Turn the ignition switch to ON.

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

Standard Voltage:

Tester Connection

Switch Condition

Specified Condition

A69-29 (W) - Body ground

Ignition switch to ON

11 to 14 V
OK

REPLACE ECM

NG

7.

CHECK HARNESS AND CONNECTOR (COMBINATION METER ASSEMBLY - ECM)

(a) Disconnect the D146 combination meter assembly connector.

(b) Disconnect the A69 ECM connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

D146-12 (CHK) - A69-29 (W)

Always

Below 1 Ω
OK

REPLACE COMBINATION METER ASSEMBLY

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR