Toyota training body electrical diagnosis ch02

The EWD includes: • Overall wiring diagram • Diagrams for every system circuit • Power source diagrams • Ground points • Junction block and relay locations • Location of components • El

Trang 1

652 Body Electrical Diagnosis

Trang 2

The Toyota Electrical Wiring Diagram (EWD) is the roadmap to all

the electrical components and wiring in Toyota vehicles The EWD is

not just a book of wiring diagrams, but an information resource for

anything electrical on the vehicle The EWD includes:

•  Overall wiring diagram

•  Diagrams for every system circuit

•  Power source diagrams

•  Ground points

•  Junction block and relay locations

•  Location of components

•  Electrical wire routing

•  System operation and troubleshooting hints

•  Terms, symbols, abbreviations, and definitions

•  Information on “How to Use This Manual”

For the most part, the printed EWD manual and the EWD on TIS contain the same information When there are differences, they will

be noted during this course TIS, however, provides different ways

to locate information in the EWD and also provides

cross-The Electrical

Wiring Diagram

NOTE

Trang 3

Because the EWD contains so much information, it takes a little time

to learn where the information is located and what the diagrams and symbols can tell you We will take a detailed look at all of these features, and how to use them in diagnosing an electrical problem

The first page of the printed EWD is an index to all the sections of the manual

With the large number of pages and sections in the EWD, the fastest way to find the diagram or information you need is to use the index

The example illustrated here is the index for the 2010 Camry It is representative of all the EWDs from 1990 to present with the following exceptions:

•  The Part Number of Connectors section was not introduced until the 1999 model year Prior to that year, connector part numbers

are not included in the EWD

•  The Connector List section was not introduced until the 2000 model year For earlier years, connectors are listed with the

system circuits to which they belong

The Index

EWD Overview

Trang 4

The majority of your troubleshooting efforts will involve using the

system circuit diagrams In the System Circuit Diagram section of

the printed EWD, you will find the index to the diagrams for every circuit on the vehicle All the other sections of the EWD provide supporting information for these diagrams

System Circuits Index

Trang 5

For the 2005 model year and earlier vehicles, the EWD on TIS is an electronic version of the printed manual, containing all the same information as the paper EWD

Because it is an electronic version of the manual, however, navigating the EWD is different than flipping the pages of a book

Taking advantage of the computer’s capabilities, the EWD uses a

“tree” on the left side of the screen for primary navigation To use the tree, simply click on any of the titles in the list

The tree is arranged alphabetically in several levels The illustration shows where the index is found – in the “General” section under

“Introduction.” On TIS, however, you would not use the index to find what you’re looking for You would use the tree

Because of the different way of navigating the EWD on TIS, this section occasionally describes how you would find information using the tree on TIS

EWD on TIS – 2005 MY

and Earlier

Trang 6

Beginning with 2006 model year vehicles, the interface for viewing the EWD on TIS is different The information on TIS is the same as

in the paper EWD, but it is arranged very differently to take advantage of the computer’s power and convenience

In this section, you will initially learn what information is available in the EWD and how to use it by primarily referring to the printed EWD manual, and possibly referring to TIS for pre-2006 vehicles

Later in this section, you will learn how to access the same information using the EWD Viewer for 2006 MY and later vehicles

EWD on TIS – 2006 MY

and Later

Trang 7

The system circuit diagrams display most of the information about

the circuit using symbols, abbreviations, and color coding To

troubleshoot the circuit, you need to know how to read these symbols and codes

You will find a detailed explanation of the symbols and codes in the

“How to Use This Manual” section of the EWD (the top half is illustrated above)

Things to note on this page:

B.  Relay blocks are noted by clear ovals with the number of the relay block inside

C.  Parentheses by wires indicate model specific wiring

E.  Wiring harness connectors are illustrated by clear rectangles with the name of the connector inside The arrows are on the male connector side

J.  Junction blocks are shown as grey boxes with the connector number inside an oval and the terminal number next to the oval

“How to Use This Manual”

Trang 8

The bottom half of the explanation for using the EWD is illustrated above

Things to note on this page:

H.  With shielded wires, do not pierce or attempt to splice!

J.  Terminal numbers are at the end of each wire, and the component’s connector name is next to the component name

K.  Ground points are shown as triangles with the ground point name inside

N.  Inner harness splice locations are always approximate 2006 and later EWDs do not number or locate splices

“How to Use This Manual”

(cont.)

Trang 9

The troubleshooting section provides basic information for:

•  Checking voltage

•  Checking continuity and resistance

•  Finding a short circuit These skills are discussed in detail in this course

Troubleshooting Section

Trang 10

The Troubleshooting section of the EWD manual also contains information on how to disconnect and reconnect connectors as well

as connector and terminal repair information

Connector Repair Information

Trang 11

If you are looking at a system circuit and find a component you

cannot identify, refer to the Glossary of Terms and Symbols

In the illustration, note the two types of Manual Switch – normally open and normally closed The state of the switch refers to its “at rest” state in the circuit

Looking at the three different kinds of Relay in the illustration (normally open, normally closed, and double throw), note they are shown with the relay coil not powered

Glossary of Terms

and Symbols

Trang 12

Sometimes switch positions can be confusing You have to think about the application to understand proper operation

•  A stop light switch is shown as a normally open switch It is only open when it is installed, and the brake pedal is not depressed

When it is not installed, it is a closed switch

•  An AC pressure switch is shown with both switches closed Both switches are only closed when the switch is installed, and the system is within normal operating pressures

Switch Positions

Trang 13

When tracing current flow through a combination switch, note the switch position, and any related circuits that may affect component operation

Tracing Current Flow

Trang 14

Note that system circuit diagrams only show the parts of components that directly relate to that circuit

In the example above, the two switches are shown differently, but they are actually the same component, a headlight switch:

•  The one on the left is from the headlight system circuit

•  The one on the right is from the taillight system circuit

Junction connectors, junction blocks, and relay blocks are other examples of component illustrations that will only show the part of the component affecting the circuit

Abbreviated Illustrations

Trang 15

Look closely at components with multiple switches inside If they are connected by a dotted line, then the switches are tied

together and move as one (a gang-type switch)

Gang-type Switches

Trang 16

Use this space to write down any questions you may have for your instructor

NOTES:

Trang 17

Two kinds of relays used in Toyota vehicles are conventional mechanical relays and solid state relays (shown above)

•  Mechanical relays are always shown with the coil OFF

•  Solid state relays are always part of a relay box and are not serviceable (You must replace the entire relay box.)

It is important to know how solid state relays operate in order to troubleshoot them

•  The power source (B+) and power out are shown as 3 connectors in a row The middle connector has a diode installed

to prevent current surges

•  The single connection on the top turns the solid state relay ON when it is grounded

You have to look at the system circuit diagram and consult the system outline in the EWD or Repair Manual to determine proper operation for each solid state relay application

Relays

Trang 18

Solid state relays are actually transistors– miniaturized electronic components that have a purpose similar to mechanical relays

Transistors, like relays, allow a circuit with low current to control a circuit with high current

Solid State Relays

Trang 19

System circuit diagrams contain a large amount of information, in

both written and graphical form, including:

•  Wire colors

•  Junction and relay block identification

•  Component and part identification

•  Connectors and pin numbers

•  Wire harness connectors

•  Switches and relays

•  Splice points

•  System outline and service hints

To effectively use this information you need to know the meanings of the abbreviations and symbols You also need to know how to use

the cross reference tables to find information in other support

sections of the EWD

The positions of switches and relays in the system circuit diagrams are based on the vehicle being off, with no keys in the vicinity and

no one touching the vehicle

Reading the System

Circuit Diagram

NOTE

Trang 20

Some system circuit diagrams include a System Outline When

troubleshooting a circuit, you should always review the System Outline (when it is available) to help you understand how the

circuit works This is especially important in circuits with logic components because the internal logic is not always obvious from the circuit diagram

When a System Outline is not provided, use the system description

in the Repair Manual or New Car Features manual

The system circuit diagram frequently includes Service Hints that

can be helpful in diagnosis

System Outline

Service Hints

NOTE

Trang 21

Sometimes it’s the small things that make a big difference in successfully troubleshooting a circuit For example, some diagrams include important notes

Always read the title at the top of the diagram carefully In some

cases you may have one circuit diagram for a “Headlight Circuit with Daytime Running Lights,” and a another diagram for “Headlight Circuit without Daytime Running Lights.” Trying to troubleshoot the circuit using the wrong diagram can be frustrating

Also watch for asterisks (*), and parentheses ( )

•  Asterisks alert you to different wiring or connections based

upon model, engine type, California, Federal, or Canadian specifications

•  Parentheses are another way you may be alerted to specific

conditions or specifications

Important Notes

Trang 22

Besides being shown in color, wire colors are also indicated by an alphabetical code next to each of the wires The first letter represents the basic wire color, and the second letter indicates the color of the

“stripe” on the wire

•  Color Codes

As you look at the list of color codes, note that the color blue uses the letter “L” to distinguish it from the letter “B” used for “black.” The color purple uses the letter “V” (for violet) to distinguish it from the letter” P” used for pink

•  Component Pigtails The wire colors of component pigtails (such as on a tail lamp) are

not shown in the EWD The colors in the EWD represent the

vehicle harness up to where it is connected to the component

•  Silver Bands on the Wire Insulation

On some wires you will find small silver “bands.” These bands (which are not shown on the wiring diagram) indicate that the wire uses a

PVC insulation This insulation is lighter in weight and thinner than

the normal insulation, making the wire diameter appear smaller than

it actually is (It may look like a 20 gauge wire on the outside, but is really 16 gauge when the wire strands are examined.)

Wire Identification

Trang 23

In some newer models, a wire harness may be made completely from white wiring, such as the 2010 Prius front door wire harness

For wire color identification, paint stripes are applied near connector terminals

Wire color codes shown in the EWD are the same as other models

Note the examples shown above for wire color identification

Painted Wire Harnesses

Trang 24

Shielding is used on low voltage or low current wires such as those

for the oxygen sensor, knock sensor, and distributor G and Ne signals When a wire is shielded, an additional ground wire is wrapped around the insulation of the low current wire to absorb any electro-magnetic interference

In the EWD, shielding is represented by a dotted line around a wire

When checking for voltage in a circuit that uses shielded wires,

NEVER puncture the insulation with the test probe! This will

short the sensor wire to the ground wire

Shielding

CAUTION

Trang 25

In the system circuit diagram, all loads, relays, switches, junction connectors, ECUs and ECU-type controllers, capacitors (noise filters), and isolation diodes are treated as components Components are color coded light blue in the diagram

Each component is identified by a connector code and the component name The codes appear in a list following the diagram with a cross

reference to the page number in the Electrical Wire Routing section

which shows the component’s location in the vehicle

Although on TIS you can find the Electrical Wire Routing section under “Power Source/Network” in the tree, you can also go directly to that section by clicking on the blue hyperlinked page number in the cross reference table

Components and

Connectors

Component Location

Trang 26

Components are wired into a circuit using connectors that can be

disconnected to make removing and replacing components easier

The component identifier is also the connector ID number

The Connector List section of the EWD contains diagrams of every

component connector in the vehicle (Harness-to-harness connectors are found in the Electrical Wire Routing section,

discussed in detail later.)

A connector diagram assigns pin numbers to each of the terminals

in the connector The same pin numbers appear at the component’s circuit connections in the system circuit diagram so you can trace current flow to and through the component

To find the Connector List on TIS, look under “General” in the tree

Remember the Connector List did not begin appearing in the EWD until the 2000 model year Prior to 2000, diagrams of a circuit’s connectors appear at the end of the system circuit diagram, in both the printed manual and on TIS

Component Connectors

Connector List

NOTE

Trang 27

Some components are wired into a circuit using more than one connector When this occurs, multiple connector ID numbers are shown above the component name

So you can identify which pin numbers on the component in the

diagram belong to which connector, a letter follows the connector

ID number The letter next to the pin number identifies which

connector it is in

Multiple Component

Connectors

Trang 28

Beginning with the 1999 model year, the EWD includes the Part Number of Connectors section

On TIS, you can find this section under “General” in the tree

Part Number of Connectors

Trang 29

Connector pin numbers are always shown from the mating side of

the connector, not the harness side of the connector

If you are backprobing the connector for a voltage check,

remember the pin numbering becomes the mirror of what is pictured

in the diagram (Use the wire color in the wiring diagram to “double

check” that you are looking at the correct pin.) Pin numbering for connectors with female terminals goes from left to right across each row, beginning at the top row For connectors with male terminals, the numbering is right to left

“Male” and “female” refer to the metal terminals, not the plastic connector shell

An “X” indicates that a terminal cavity is not used

For 1999 model year and earlier vehicles (before the Connector List section was added to the EWD), connector diagrams are found at the end of each system circuit diagram These diagrams use a dot (“•” ) to indicate cavities that are used by another circuit

Pin Numbering

Color Coding

NOTE

Trang 30

The wiring for most vehicle circuits passes through one or more junction blocks (J/Bs) or relay blocks (R/Bs) J/Bs and R/Bs are

often convenient test points because they contain connections to so many circuits Understanding how to find those test points for a particular circuit is a critical skill in diagnosing electrical problems

Junction blocks distribute power and ground to various circuits

Inside the junction block, layers of insulated, solid metal plates create internal connections between the pins of different connectors This eliminates the need for many additional splices, and improves reliability

On the wiring diagram, junction blocks are color-coded gray Note the diagram does not show the entire junction block It shows only

the part of the junction block that affects the circuit

Connections to the J/B are indicated with an oval Inside the oval is

a number or letter followed by a letter which together are the J/B

ID The number part of the ID represents the J/B location For

Trang 31

The letter part of the J/B ID in the oval indicates a specific connector

to the junction block, and the number beside the oval is the pin number in that connector

•  The J/B ID appears in a cross reference list following the system circuit diagram with the page number of the J/B diagram in the

Relay Locations section

•  On TIS, clicking on the blue page number takes you directly to the J/B diagram

The Relay Locations section of the EWD provides several kinds of information about junction blocks, including:

•  Part locations

•  J/B diagrams

•  Connector diagrams

•  Inner circuit

On TIS, besides clicking on the hyperlinked page number to reach

the J/B diagram, you can also find the Relay Locations section under “Power Source/Networking” in the tree Whatever way

you arrive there, you can scroll through the section to find the

Junction Block Location

Trang 32

If a circuit is dead, shorted, or has a feedback problem, the Repair Manual diagnostics might include tracing current flow through the junction block’s inner circuit Information on J/B inner circuits is provided in the Relay Locations section

J/B Inner Circuit

Trang 33

A relay block acts as a central location for relays and fuses

Although similar in appearance to a junction block, relay blocks are different because they do not have internal circuits to distribute power or ground

Relay blocks in the system circuit diagram are not color-coded, but

are usually connected to a component such as a relay or a fuse, which is color-coded light blue You’ll know the component is at a

relay block because the component connections are indicated with an oval

Inside the oval is the R/B ID number A letter is not used to identify

the connector because the R/B does not have separate connectors

The R/B ID appears in a cross reference list following the system circuit diagram with the page number of the R/B diagram in the

Relay Location section

On TIS, clicking on the blue page number takes you directly to the Relay Location section where you can find the R/B diagram

Relay Blocks

Trang 34

Complex automotive wiring involves many points where wiring is joined

or divided by junction connectors, harness connectors and splice points

Each of these points in a circuit offer opportunities for problems, and possibly convenient places for circuit testing

Understanding how these connection points are represented in circuit diagrams, and how to find them in the vehicle can be essential to diagnosing some types of electrical problems

A junction connector is a component with internal circuits for distributing current or ground It is much simpler than a junction block and performs the same function as a splice, but a junction connector is more reliable than a splice

As a component, it has component connectors identified by connector

ID numbers above the component name in the system circuit diagram

The junction connector may distribute current for more than one circuit

The system circuit diagram shows only the part of the junction connector that affects that circuit

Because it is treated as a component, the procedure for finding its location and other part information is the same as for other components

Junction Connectors,

Harness Connectors

and Splice Points

Junction Connectors

Trang 35

Because it is considered a component, the junction connector’s connectors are found in the Connector List

When the junction connector has more than one connector, the connector IDs in the system circuit diagram include a circled letter shown at each pin to indicate which connector it is in

A second diagram uses connecting lines between the terminals to indicate which terminals are wired together inside the junction connector Within the connector, these terminals are electrically connected when the parts are assembled

Junction Connector

Connectors

Định dạng
Số trang	70
Dung lượng	20,04 MB