Toyota Tundra Service Manual: MIL Circuit

DESCRIPTION

The Malfunction Indicator Lamp (MIL) is used to indicate vehicle malfunctions detected by the ECM.

The MIL operation can be checked visually. When the ignition switch is turned to ON, the MIL should be illuminated and should then turn off after the ignition switch is turned to ON. If the MIL remains illuminated or is does not illuminate, conduct the following troubleshooting procedure.

WIRING DIAGRAM

PROCEDURE

1.

CHECK THAT MIL IS ILLUMINATED

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

MIL

Condition

Proceed to

Illuminates → Turns off

Ignition switch off → Ignition switch ON

A

Other than above

-

B

A

CHECK FOR INTERMITTENT PROBLEMS

B

2.

CHECK COMMUNICATION BETWEEN TECHSTREAM AND ECM

(a) Connect the Techstream to the DLC3.

(b) Turn the ignition switch to ON.

(c) Turn the Techstream on.

(d) Check the communication between the Techstream and ECM.

HINT:

Communication can be checked by using the Data List item Engine.

Result

Proceed to

Communication is possible

A

Communication is not possible

B

B

GO TO VC OUTPUT CIRCUIT

A

3.

CHECK WHETHER DTC OUTPUT RECURS

(a) Connect the Techstream to the DLC3.

(b) Turn the ignition switch to ON.

(c) Turn the Techstream on.

(d) Enter the following menus: System Select / Health Check.

(e) Check if any DTCs have been detected. Note down any DTCs.

Result

Proceed to

DTCs are not output

A

DTCs are output

B

HINT:

Check for detected DTCs output from other ECUs which relate to the MIL.

B

REPAIR CIRCUITS INDICATED BY OUTPUT DTCS

A

4.

PERFORM ACTIVE TEST USING TECHSTREAM

(a) Connect the Techstream to the DLC3.

(b) Turn the ignition switch to ON.

(c) Turn the Techstream on.

(d) Enter the following menus: Body Electrical / Combination Meter / Active Test / Check Engine Indicator.

Body Electrical > Combination Meter > Active Test

Tester Display

Check Engine Indicator

(e) According to the display on the Techstream, perform the Active Test and check the operation of the MIL.

Result

Proceed to

Changes

A

Does not change

B

A

REPLACE ECM

B

REPLACE COMBINATION METER ASSEMBLY

    Initialization

    MAP - Mass or Volume Air Flow Correlation Bank 1 (P006A)

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