Toyota Tundra. Manual — part 20

7. CIRCUIT INSPECTION

A description of the main areas of each circuit inspection is below.

CIRCUIT INSPECTION DESCRIPTION TABLE

ELECTRONIC CIRCUIT INSPECTION PROCEDURE

1. BASIC INSPECTION

a. WHEN MEASURING RESISTANCE OF ELECTRONIC PARTS

1. Unless otherwise stated, all resistance measurements should be made at an ambient

temperature of 20°C (68°F). Resistance measurements may be inaccurate if measured at high
temperatures, i.e. immediately after the vehicle has been running. Measurements should be
made after the engine has cooled down.

b. HANDLING CONNECTORS

1. When disconnecting a connector, first squeeze the mating halves tightly together to release

the lock, and then press the lock claw and separate the connector.

2. When disconnecting a connector, do not pull on the harnesses. Grasp the connector directly

and separate it.

3. Before connecting a connector, check that there are no deformed, damaged, loose or missing

terminals.

4. When connecting a connector, press firmly until it locks with a "click" sound.

5. If checking a connector with a TOYOTA electrical tester, check the connector from the

backside (harness side) using a mini test lead.

Item

Description

Circuit Description

The major role and operation of the circuit and its component parts are
explained.

DTC Code, DTC
Detection Condition,
Trouble Area

Indicates the diagnostic trouble codes, diagnostic trouble code detection
conditions, and trouble areas of a problem.

Wiring Diagram

This shows a wiring diagram of the circuit. Use this diagram together with an
ELECTRICAL WIRING DIAGRAM to thoroughly understand the circuit.

Inspection Procedures

Use the inspection procedures to determine if the circuit is normal or abnormal.
If abnormal, use the inspection procedures to determine whether the problem is
located in the sensors, actuators, wire harnesses or ECU.

Inspection Procedure
Connector Graphics



Connector being checked is connected:

Connections of tester are indicated by (+) or (-) after the terminal name.



Connector being checked is disconnected:

For graphics of inspections between a connector and body ground,
information about the body ground is not shown in the graphic.

2009 Toyota Tundra

2009 GENERAL INFORMATION Introduction - Tundra

c. CHECKING CONNECTORS

1. Checking when a connector is connected: Squeeze the connectors together to confirm that

they are fully connected and locked.

2. Checking when a connector is disconnected: Check by pulling the wire harness lightly from

the backside of the connector. Look for unlatched terminals, missing terminals, loose crimps
or broken conductor wires. Check visually for corrosion, metallic or foreign matter and
water, and bent, rusted, overheated, contaminated, or deformed terminals.

NOTE:



As a waterproof connector cannot be checked from the
backside, check it by connecting a sub-harness.



Do not damage the terminals by moving the inserted tester
needle.

Fig. 55: Identifying Correct And Incorrect Methods Of
Handling Connectors
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

2009 Toyota Tundra

2009 GENERAL INFORMATION Introduction - Tundra

Fig. 56: Precaution For - Checking Connectors
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

3. Checking the contact pressure of the terminal: Prepare a spare male terminal. Insert it into a

female terminal, and check for ample tension when inserting and after full engagement.

Fig. 57: Identifying Contact Pressure Of Terminal
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

d. REPAIR METHOD OF CONNECTOR TERMINAL

1. If there is any foreign matter on the terminal, clean the contact point using an air gun or

cloth. Never rub the contact point using sandpaper as the plating may come off.

2. If there is abnormal contact pressure, replace the female terminal. If the male terminal is

gold-plated (gold color), use a gold-plated female terminal; if it is silver-plated (silver color),
use a silver-plated female terminal.

3. Damaged, deformed, or corroded terminals should be replaced. If the terminal does not lock

into the housing, the housing may have to be replaced.

NOTE:

When testing a gold-plated female terminal, always use a gold-
plated male terminal.

2009 Toyota Tundra

2009 GENERAL INFORMATION Introduction - Tundra

Fig. 58: Identifying Correct And Incorrect Methods Of Repairing Connector Terminal
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

e. HANDLING OF WIRE HARNESS

1. If removing a wire harness, check the wiring and clamping before proceeding so that it can

be restored in the same way.

2. Never twist, pull or slacken the wire harness more than necessary.

3. The wire harness should never come into contact with a high temperature part, or rotating,

moving, vibrating or sharp-edged parts. Avoid contact with panel edges, screw tips and other
sharp items.

4. When installing parts, never pinch the wire harness.

5. Never cut or break the cover of the wire harness. If it is cut or broken, replace it or repair it

with vinyl tape.

Fig. 59: Identifying Correct And Incorrect Methods Of Handling Wire Harness
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

2. CHECK FOR OPEN CIRCUIT

a. For an open circuit in the wire harness in Fig. 60, check the resistance or voltage, as described

below.

2009 Toyota Tundra

2009 GENERAL INFORMATION Introduction - Tundra