Toyota Tundra Service Manual: Problem Symptoms Table

PROBLEM SYMPTOMS TABLE

HINT:

Use the table below to help determine the cause of problem symptoms. If multiple suspected areas are listed, the potential causes of the symptoms are listed in order of probability in the "Suspected Area" column of the table. Check each symptom by checking the suspected areas in the order they are listed. Replace parts as necessary.

Touch select 2-4 and high-low system

Symptom

Suspected Area

See page

When the vehicle is in the 2WD state and the transfer position switch is turned to a position other than 2WD, the 4HI and 4LO indicator lights are not illuminated

CAN communication system

Combination meter assembly

Transfer position switch (open circuit in LO terminal circuit or stuck OFF)

4 wheel drive control ECU

When the vehicle is in the 4H state and the transfer position switch is turned to a position other than 4H, the 4HI indicator light is illuminated and the 4LO indicator light is not illuminated

Transfer position switch (short circuit in 2-4 or LO terminal circuit or stuck ON)

4 wheel drive control ECU

When the vehicle is in the 4L state and the transfer position switch is turned to a position other than 4L, the 4HI indicator light is not illuminated and the 4LO indicator light is illuminated

Transfer position switch (open circuit in 2-4 terminal circuit or stuck OFF)

4 wheel drive control ECU

CAN communication system

The 4HI indicator light is blinking* after operation of the transfer position switch

A.D.D. actuator (differential vacuum actuator assembly)

Transfer shift actuator assembly (transfer shift motor)

A.D.D. actuator (differential vacuum actuator assembly) (A.D.D. shift motor)

4 wheel drive control ECU

The 4LO indicator light is blinking* after operation of the transfer position switch

Transfer shift actuator assembly (transfer shift motor)

4 wheel drive control ECU

  • *: Blinks at 0.5 second intervals (0.5 seconds on and 0.5 seconds off)
    Precaution

    Shift Motor Circuit

    See More:

    Toyota Tundra Service Manual > Throttle Body: On-vehicle Inspection
    ON-VEHICLE INSPECTION PROCEDURE 1. CHECK THROTTLE BODY ASSEMBLY (a) Check the throttle control motor operating sounds. (1) Turn the ignition switch to ON. (2) When depressing the accelerator pedal, check the operating sound of the running motor. Make sure that no friction noises emit from the motor. ...

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    Toyota Tundra Service Manual

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