31S10T0 engine peformance theory and operation 2006

The Engine Performance Diagnosis and Testing classroom course includes the following: • Instructor-led Discussion – You are asked to complete review questions that address content previo

Appropriate service methods and proper repair procedures are essential for the safe, reliable operation of all motor vehicles,

as well as the personal safety of the individual doing the work This manual provides general directions for accomplishing service and repair work with tested, effective techniques Following them will help assure reliability

There are numerous variations in procedures, techniques, tools and parts for servicing vehicles, as well as in the skill of the individual doing the work This manual cannot possibly anticipate all such variations and provide advice or cautions as to each Accordingly, anyone who departs from instructions provided in this manual must first establish that he compromises neither his personal safety nor the vehicle integrity by his choice of methods, tools or parts

As you read through the procedures, you will come across NOTES, CAUTIONS, and WARNINGS Each one is there for a specific purpose NOTES give you added information that will help you to complete a particular procedure CAUTIONS are given to prevent you from making an error that could damage the vehicle WARNINGS remind you to be especially careful in those areas where carelessness can cause personal injury The following list contains some general WARNINGS that you should follow when you work on a vehicle

The recommendations and suggestions contained in this manual are made to assist the dealer in improving his dealership parts and/or service department operations These recommendations and suggestions do not supersede or override the provisions of the Warranty and Policy Manual, and in any cases where there may be a conflict, the provisions of the Warranty and Policy Manual shall govern

The descriptions, testing procedures, and specifications in this handbook were in effect at the time the handbook was approved for printing Ford Motor Company reserves the right to discontinue models at any time, or change specifications, design, or testing procedures without notice and without incurring obligation Any reference to brand names in this manual is intended merely as an example of the types of tools, lubricants, materials, etc recommended for use Equivalents, if available, may be used The right is reserved to make changes at any time without notice

WARNING: MANY BRAKE LININGS CONTAIN ASBESTOS FIBERS WHEN WORKING ON BRAKE COMPONENTS, AVOID BREATHING THE DUST BREATHING THE ASBESTOS DUST CAN CAUSE ASBESTOSIS AND CANCER

• Always wear safety glasses for eye protection

• Use safety stands whenever a procedure requires you to

be under the vehicle

• Be sure that the ignition switch is always in the OFF

position, unless otherwise required by the procedure

• Set the parking brake when working on the vehicle If you

have an automatic transmission, set it in PARK unless

instructed otherwise for a specific service operation If you

have a manual transmission it should be in REVERSE

(engine OFF) or NEUTRAL (engine ON) unless instructed

otherwise for a specific service operation

• Operate the engine only in a well-ventilated area to avoid

the danger of carbon monoxide

• Keep yourself and your clothing away from moving parts

when the engine is running, especially the fan and belts

• To prevent serious burns, avoid contact with hot metal parts such as the radiator, exhaust manifold, tail pipe, catalytic converter and muffler

• Do not smoke while working on the vehicle

• To avoid injury, always remove rings, watches, loose hanging jewelry, and loose clothing before beginning to work on a vehicle Tie long hair securely behind your head

• Keep hands and other objects clear of the radiator fan blades Electric cooling fans can start to operate at any time by an increase in underhood temperatures, even though the ignition is in the OFF position Therefore, care should be taken to ensure that the electric cooling fan is completely disconnected when working under the hood

CUSTOMER EXPECTATIONS

Expectation 3

“Fix It Right The First Time, on Time.”

Both service advisors and technicians are important players when it comes to Expectation #3

Why

Customers tell us “Fixing It Right The First Time, on Time” is one of the reasons they

would decide to return to a dealer to buy a vehicle and get their vehicles serviced

Technician Training

It is our goal to help the technician acquire all of the skills and knowledge necessary to

“Fix It Right The First Time, on Time.” We refer to this as “competency.”

Technician’s Role

Acquire the skills and knowledge for competency in your specialty via:

– FordStar Broadcasts – FordStar Broadcasts

– Ford Multimedia Training (FMT) – Instructor Led

– Instructor Led

The Benefits

The successful implementation of expectations means:

– Satisfied customers

– Repeat vehicle sales

– Repeat service sales

– Recognition that Ford and Lincoln/Mercury technicians are “the Best in the Business”

Customer Expectations: Service

1. Make it convenient to have my vehicle

serviced at your dealership

2. The Service Advisor should

demonstrate a genuine concern for my

service needs

3. Fix it right the first time

4. Complete servicing my vehicle in a

timely and professional manner

5. Provide me with a clear and thorough explanation of the service performed

6. Call me within a reasonable amount of time after my service visit to ensure that I'm completely satisfied

7. Be responsive to questions or concerns

I bring to your attention

Engine Performance Curriculum Goals Intro 1 Planned Training Pathway Intro 1 Engine Performance Curriculum Overview Intro 1 How to Complete the Curriculum Intro 2 Course Description Intro 3 Course Length Intro 3 Target Audience Intro 3 Course Prerequisites Intro 3 Course Structure Intro 3 Course Objectives Intro 4 Classroom Multimedia Training (CMT) Intro 5 PC-Assisted Activities Intro 5 Evaluation Strategy Intro 5 Day One Flowchart Intro 6 Day Two Flowchart Intro 7 Day Three Flowchart Intro 8 Day Four Flowchart Intro 10

DIAGNOSTIC PROCESS REVIEW

Student Objectives 1-1 SSCC Process 1-2 Diagnostic Process 1-7 Diagnostic Tests 1-17 Electronic PC/ED Worksheet 1-23 On-Vehicle Worksheet 1-24

IGNITION SYSTEM DIAGNOSIS AND TESTING

Student Objective 2-1 Ignition Concerns 2-2 Misfire Diagnosis 2-4 COP Misfire Diagnosis 2-8

No Start Condition Diagnosis 2-13 Ignition Bench Worksheet 2-14 Ignition COP On-Vehicle Worksheet 2-15 Ignition HDR On-Vehicle Worksheet 2-16

FUEL SYSTEM DIAGNOSIS AND TESTING

Student Objective 3-1

TABLE OF CONTENTS

AIR INLET DIAGNOSIS AND TESTING

Student Objective 5-1 IAC Valve 5-2 Controlled Air Inlet Systems 5-5

PASSIVE ANTI-THEFT SYSTEM (PATS)

Student Objective 6-1 Basic PATS 6-2 Integrated PATS (IPATS) 6-3 Engine Performance Concerns Unrelated to PATS 6-4

EMISSIONS SYSTEM DIAGNOSIS AND TESTING

Student Objective 7-1 Positive Crankcase Ventilation (PCV) 7-2 Exhaust Gas Recirculation (EGR) 7-5 Thermostat Heater Control 7-10 Catalysts 7-13 Evaporative Emissions (EVAP) System 7-16 EVAP Worksheet 7-24 OBD Test Modes Worksheet 7-25 EGR / IAC Worksheet 7-26

DAY THREE WORKSHEETS

Worksheet 1 (WDS EVAP Diagnosis – Hands-on) WS3-3 Worksheet 2 (MIL ON – PC Assisted) WS3-4 Worksheet 3 (Runs Very Rough at Idle – Hands-on) WS3-6 Worksheet 4 (Crank/No Start CMT) WS3-8

DAY FOUR WORKSHEETS

Worksheet 1 (No Start – Hands-on) WS4-2 Worksheet 2 (Engine Runs Rough – PC Assisted) WS4-6 Worksheet 3 (Hesitation on Acceleration – Hands-on) WS4-8 Worksheet 4 (Engine Runs Rough – CMT) WS4-10

ENGINE PERFORMANCE CURRICULUM GOALS

The goal of the Engine Performance Curriculum is to provide you with the necessary training to enable you to

”Fix it right the first time – on time.” This Engine Performance Diagnosis and Testing classroom course provides you with hands-on practice as it relates to diagnosis and testing

Planned Training Pathway

Ford Motor Company has identified the skills and knowledge necessary to meet the Engine Performance

Curriculum goals The Planned Training Pathway is a sequence of courses that are designed to provide students with these skills and knowledge

Engine Performance Curriculum Overview

The Engine Performance Curriculum consists of all of the following types of courses:

Web-based – These courses are self-paced You are responsible for learning the material on your own time The courses are posted on the Internet and you are given the appropriate access codes

Classroom – The classroom courses allow for application of the skills and knowledge learned in the prerequisite courses through hands-on, real-world scenarios

INTRODUCTION

How to Complete the Curriculum

To successfully complete the Engine Performance Curriculum, you must take the following sequence of courses:

Ignition System Theory and Operation -

Ignition Theory and Operation –

The Engine Performance Diagnosis and Testing classroom course includes the following:

• Instructor-led Discussion – You are asked to complete review questions that address content previously covered in the WBT courses Instructor-led group discussions focus on critical thinking skills and specific concepts that are critical when following a diagnostic process to identify a faulty component or circuit

• Instructor Lecture – The instructor presents new information as it relates to guided diagnosis and testing

• Student Activities – The student activities are designed to reinforce concepts presented during the instructor lecture

• Workstations – The instructor presents the concepts that are critical to successfully completing the

workstations You participate in four on-vehicle hands-on exercises, two classroom media training (CMT) activities delivered on CD-ROM, and two PC-assisted activities during the workstation portion of the course

• Worksheets – All activities and workstations have an accompanying worksheet designed to complement the hands-on activities Day One and Day Two student activity worksheets are identified by name Day Three and Day Four worksheets are identified by number

• Evaluation – At the end of the four-day course, the instructor asks you to complete a final written test, a final hands-on workstation, and a course evaluation

INTRODUCTION

Course Objectives

Upon completion of the Engine Performance Diagnosis and Testing classroom course, you will be able to:

• Use the SSCC diagnostic process to diagnose engine performance concerns

• Explain how to perform diagnostic tests

− Quick Tests

KOEO on-demand self-tests, KOER on-demand self tests, Continuous memory self-tests

− PID Monitor

• Explain PCM circuits and wiring

• Use critical thinking skills and available resources to diagnose and test specific engine performance systems,

including:

− Ignition system

Identify the types of misfires

Explain the relationship of ignition patterns to diagnosis

Explain how to diagnose misfire concerns

Explain how to diagnose no start concerns

− Fuel System

Fuel delivery

⇒ Identify the types of fuel delivery systems

⇒ Describe conditions related to fuel delivery concerns

⇒ Describe the testing related to fuel delivery concerns

Fuel control

⇒ Describe how to diagnose a contaminated MAF sensor

⇒ Identify open/closed loop conditions

⇒ Explain conditions related to abnormal fuel trims

⇒ Describe the testing related to fuel control concerns

− Air Inlet System

Explain the conditions and tests related to diagnosing and testing the IAC valve

Explain the conditions and tests related to diagnosing and testing Controlled Air Inlet Systems

− Exhaust/Emissions System

Explain the conditions and tests related to diagnosing specific emission systems, including PCV,

EGR, CAT, and EVAP

• Explain the basic operation of the Passive Anti-Theft System (PATS)

• Using available resources, perform hands-on diagnosis and testing of specific engine performance systems

including, Ignition, Fuel, Air Inlet, and Emissions

Classroom Multimedia Training (CMT)

The CMTs are workstation activities delivered via CD and include video and audio elements These are

simulated hands-on practice in diagnosis and testing of driveability concerns The PCED information is included

in each activity The CMTs include:

• Scenarios – These are DTC driven routines that address driveability concerns

• Interactive Exercises – These exercises allow you the opportunity to apply the information presented during instruction

PC-Assisted Activities

The PC-assisted activities are workstation activities delivered via CD They do not include the use of video and audio elements These are simulated hands-on practice in diagnosis and testing of driveability concerns with heavy emphasis in using the actual PCED (hard copy or electronic) The PC-assisted activities include:

• Scenarios – These are DTC driven routines that address driveability concerns

• Interactive Exercises – These exercises allow the technicians the opportunity to apply the information

presented

Evaluation Strategy

Your evaluation is based on the score of a final written test and a hands-on workstation These are completed on the afternoon of the last day A non-passing grade in either of these two evaluation areas constitutes a failing grade for the course There are no make-up tests or "do-overs" available Any technician that fails this course must sign up to take the course for a second time

Final Written Test

You complete the final written test at your seat The written test consists of 30 multiple-choice questions The questions focus on diagnostic concerns and processes identified during the classroom session and require critical thinking skills to solve problems You must correctly answer 80% of these questions (24 of 30 questions) to pass

Final Hands-on Workstation

You must diagnose the final hands-on workstation and correctly answer all of the accompanying worksheet questions with 100% accuracy The hands-on activity is done without instructor assistance and the worksheet must be completed individually You may use all of the reference material available to you in the classroom, including workshop manuals and the student reference book

INTRODUCTION

Day One Flowchart

• PCM Wiring and

Circuits Review

Ignition System Activities

End of Day One

Instructor

Introduction

Review Questions

Day Two Flowchart

Fuel System

INTRODUCTION

Day Three Flowchart

Day Three Workstations

• Rotation 1

• Rotation 2

Lunch

Break

Review of Day One

and Day Two

Review of Day Three Worksheets

Introduction of Day Three Workstations

Day Three

Workstations

• Rotation 3

• Rotation 4

DAY THREE WORKSTATION ROTATIONS

Team 3 –

Worksheet 4 Crank/No Start (CMT)

Team 3 –

Worksheet 1 EVAP - Smoke Tester (Hands-on)

Team 4 –

Worksheet 2 MIL On (PC-assisted)

Team 4 –

Worksheet 3 Runs Very Rough at Idle (Hands-on)

Team 4 –

Worksheet 1 EVAP - Smoke Tester (Hands-on)

Team 2 –

Worksheet 1 EVAP - Smoke Tester (Hands-on)

Team 2 –

Worksheet 4 Crank/No Start (CMT)

Team 1 –

Worksheet 3 Runs Very Rough at Idle (Hands-on)

Team 1 –

Worksheet 4 Crank/No Start (CMT)

INTRODUCTION

Day Four Flowchart

Day Four Workstations

• Rotation 1

Break

Lunch

Day Four Workstations

Review of Day Four

Worksheets

End of Day Four

DAY FOUR WORKSTATION ROTATIONS

Team 1 –

Worksheet 3 Hesitation on Acceleration (Hands-on)

Team 1 –

Worksheet 4 Engine Runs Rough (CMT)

Team 2 –

Worksheet 3 Hesitation on Acceleration (Hands-on)

Team 2 –

Worksheet 4 Engine Runs Rough (CMT)

Team 2 –

Worksheet 1

No Start (Hands-on)

Team 3 -

Worksheet 2 Engine Runs Rough (PC-assisted)

Team 3 –

Worksheet 4 Engine Runs Rough (CMT)

Team 3 –

Worksheet 1

No Start (Hands-on)

Team 4 –

Worksheet 2 Engine Runs Rough (PC-assisted)

Team 4 –

Worksheet 3 Hesitation on Acceleration (Hands-on)

Team 4 –

Worksheet 1

No Start (Hands-on)

INTRODUCTION

NOTES

Student Objectives

• Review the Diagnostic Process

• Explain how to perform diagnostic tests

− Quick Tests

− KOEO on-demand self-tests

− KOER on-demand self-tests

− Continuous memory self-tests

− Verify the symptom(s)

− Identify the conditions necessary to recreate the symptom

− Identify the system(s)

− Perform all diagnostic tests necessary to isolate the failure

− Interpret the test results

− Isolate the root cause of the failure

DIAGNOSTIC PROCESS REVIEW DAY ONE

SSCC Process

SSCC Process

Following the Symptom to System, Component to Cause (SSCC) process leads you to the failed component and

the root cause of that failure

SSCC Process

Symptom Verification

CHECK ENGINE

CHECK FUEL CAP

C

F

EP2102-A/VF

Symptom Verification - MIL “ON”

Customers bring their vehicles into the dealership because they have experienced something out of the ordinary Your first step in the diagnostic process must be to verify the symptom or concern

DIAGNOSTIC PROCESS REVIEW DAY ONE

SSCC Process

Component Identification

Testing Components

NOTE: Always use the proper flex probes when testing with the DVOM

Once the system has been identified, you must determine the component that has failed Perform the necessary tests on the suspect system to identify the failed circuit or component

DIAGNOSTIC PROCESS REVIEW DAY ONE

SSCC Process

Cause Determination

Repairing and Determining Root Cause

At this point, the symptom has been verified, the system has been identified, and the failed component/circuit has

been identified Now, the root cause must be determined to ensure that the failure does not recur

EP2105-A/VF

Diagnostic Process

The individual tasks incorporated within the SSCC process include the following:

Diagnostic Steps

DIAGNOSTIC PROCESS REVIEW DAY ONE

Diagnostic Process

Verify the Symptom(s)

Road Test/Visual Inspection

The first step is always verifying that the concern exists Verifying the symptom (customer's concern) can be as

simple as doing a visual inspection to confirm that in fact there is a failure, or as complex as an intermittent

stalling condition that needs to be captured using a Vehicle Data Recorder (VDR)

EP2107-A/VF

Diagnostic Process

Identifying Conditions

Repair Order/Consulting the Customer

The repair order is the first piece of information you receive At this point, the customer's concern is an

interpretation of the information the service advisor gathered from the customer The vehicle may have to be placed under certain conditions, such as driven under a load, turning a sharp corner, or coming to a stop, to

recreate the concern If the repair order does not clearly define those conditions, or the concern could not be

duplicated, then consult the service adviser or customer for further information

DIAGNOSTIC PROCESS REVIEW DAY ONE

Diagnostic Process

Identify Related Symptoms

Identify Related Symptoms/Systems

If the work order contains multiple symptoms, look for a relationship among those symptoms that could help you

pinpoint the failed system

As soon as the symptom(s) is verified, start a mental evaluation of what you experienced Start identifying

systems that you think could create the symptom(s) Once you have made the determination that the symptom is a driveability concern, check OASIS for information that may help isolate the system

Diagnostic Process

Identify the System(s)

OASIS/Service Publications/WDS

Once the symptom (customer’s concern) is identified, the system(s) that is causing the concern has to be

identified Use all available tools and resources to complete this step Go to the Symptom Charts section of the PC/ED and perform a Quick Test

Carefully review and evaluate all of the information downloaded from OASIS If any of the TSBs, special service messages, or open recalls relate to the symptom you have experienced, follow the directions within the

information to continue diagnosis Finally, review the service history information The service history could relate previous repairs to the symptom you are experiencing

For example, if the vehicle you are diagnosing has just had a battery replaced and now the engine idles rough for

DIAGNOSTIC PROCESS REVIEW DAY ONE

Diagnostic Process

Isolate the Failure

EP2110-A/VF

Pinpoint Test

When directed to a pinpoint test, always read the information and look at the schematic included at the beginning

of the pinpoint test Never enter a pinpoint test unless you are directed to go there

Diagnostic Process

Interpret Test Results

Throttle Position (TP) Sensor Test

NOTE: Always use the proper flex probes when testing with the DVOM

It is important to understand why you are performing a specific test, so that if the vehicle fails the test, you have a clear understanding of what made it fail You may have to use specific reference value charts to help you interpret test results

In this example, the correct voltage value is 5 volts, and the DVOM reads 5 volts This test verifies that the SIG RTN and the VREF circuits are complete and the failure lies elsewhere

DIAGNOSTIC PROCESS REVIEW DAY ONE

Diagnostic Process

Isolate the Root Cause

TP Wire Cut

The root cause of the failure must be determined to ensure the failure does not recur The root cause can be simple

or complex In either case, a thorough examination of the circumstances involved in the failure must be

performed

In this example, the root cause of the TP circuit failure is the wiring harness is routed too close to the plastic

shield The wiring harness has to be rerouted to prevent similar failures

EP2112-A/VF

Wire Repair Procedure

Item Description Item Description

repair (overlap)

together, solder wires

until adhesive flows out of both ends

*Wait for solder to cool before moving wires

Once the failure has been identified and the root cause corrected, the repair must be made Consult the Workshop Manual or Wiring Diagrams (EVTM) for proper repair procedures

DIAGNOSTIC PROCESS REVIEW DAY ONE

Diagnostic Process

Verify the repair

Worldwide Diagnostic System (WDS)

The final step of any diagnostic procedure is to verify that the repair has resolved the concern as well as not

created any new concerns Therefore, it is necessary to clear all DTCs and retest the vehicle under the same

conditions at which you originally verified the symptom This could include road testing through the entire OBD

II drive cycle, or portions of the OBD II drive cycle, as indicated at the end of the diagnostic pinpoint test

During testing procedures, you will be instructed to disconnect components and perform circuit tests This may

cause new DTCs to be set Moving components and wiring during the test may also cause new concerns The

repair is complete if you cannot recreate the concern and no new concerns are noted

EP2114-A/VF

INSTRUCTOR NOTES

Diagnostic Tests

Quick Test

QT1 – Perform PCM Quick Test

The PC/ED Quick Test directs you to retrieve all DTCs and then asks the question "Were any DTCs present?" If there are DTCs present, then select YES and proceed to the DTC Charts for further diagnosis If no DTCs are present, then select NO and proceed to the symptom charts for further diagnosis In either case, your selection leads you to charts that indicate the proper pinpoint test to start your diagnosis

DIAGNOSTIC PROCESS REVIEW DAY ONE

Diagnostic Tests

Quick Test (Continued)

DTC Retrieval Using WDS

After the concern has been verified, a visual inspection completed, and OASIS has been checked for documented

failures relating to the concern, perform a Quick Test as directed by the PC/ED

Quick Test is divided into three specialized tests:

• Key On Engine Off (KOEO) On-Demand Self-Test

• Key On Engine Running (KOER) On-Demand Self-Test

• Continuous Memory Self-Test

Quick Test checks the integrity and function of the Electronic EC System and outputs the test results when

requested by a scan tool

Quick Test also provides a quick end check of the powertrain control system It is performed at the start of each

diagnostic procedure with all accessories off Quick Test is also performed at the end of most pinpoint tests for

verification of repair and to make sure no other faults were induced while repairing a previous fault

A system pass is displayed when no DTCs are output and a scan tool communication error does not exist System

pass means that hardware monitored by the PCM is functioning within normal operating limits Only a system

pass, DTC, or an incomplete OBDII drive cycle (P1000) is displayed

EP2116-A/VF

Diagnostic Tests

Quick Test (Continued)

Key On Engine Off (KOEO) On-Demand Self-Test

The Key On Engine Off (KOEO) On-Demand Self-Test is a functional test of the powertrain control module performed on demand with the key on and the engine off This test performs checks on certain sensor and actuator circuits A fault must be present at the time of testing for the KOEO Self-Test to detect the fault When a fault is detected, a Diagnostic Trouble Code (DTC) is output on the data link at the end of the test when requested by a scan tool Depressing the clutch pedal on manual transmission vehicles may be required to prevent false DTCs

Key On Engine Running (KOER) On-Demand Self-Test

The Key On Engine Running (KOER) On-Demand Self-Test is a functional test of the powertrain control module performed on demand with the key on engine running and vehicle stopped A check of certain inputs and outputs

is made during operating conditions and at normal operating temperature The brake pedal position, transmission control and power steering switch tests are part of the KOER On-Demand Self-Test and MUST be performed during this operation if applicable These are described below A fault must be present at the time of the KOER On-Demand Self-Test to detect the fault When a fault is detected, a Diagnostic Trouble Code (DTC) is output on the data link at the end of the test when requested by a scan tool

Brake Pedal Position Test

This tests the ability of the Electronic EC system to detect a change of state in the stoplight switch Brake pedal MUST briefly be applied and released on all vehicles equipped with brake pedal position input This is done during the KOER On-Demand Self-Test

Transmission Control Switch Test

This tests the ability of the Electronic EC system to detect a change of state in the transmission control switch (TCS) The switch MUST briefly be cycled on all vehicles equipped with TCS input This is done during the KOER On-Demand Self-Test

Power Steering Pressure Test

This tests the ability of the Electronic EC system to detect a change in power steering system fluid pressure The steering wheel MUST briefly be turned at least 1/4 of a revolution on vehicles equipped with a power steering pressure (PSP) switch or sensor This is done during the KOER On-Demand Self-Test

DIAGNOSTIC PROCESS REVIEW DAY ONE

Diagnostic Tests

Quick Test (Continued)

Continuous Memory Self-Test

Testing for Continuous Memory DTCs is a functional test of the powertrain control module performed under any

condition (engine running or off) with the key on Unlike the KOEO and KOER self-tests, which can only be

activated on demand, the Continuous Memory Self-Test is always active This test detects failures contributing to

driveability or emission concerns The vehicle may need to be driven or the OBDII Drive Cycle completed to

allow the PCM to detect a fault Refer to «Drive Cycles» for more information When a fault is stored in memory,

a Diagnostic Trouble Code (DTC) is output on the data link at the end of the test when requested by a scan tool

Continuous Memory DTCs are especially valuable when diagnosing intermittent faults because a fault does not

need to be present at the time of testing

There are two types of Continuous Memory DTCs The first type is an emission related malfunction indicator

lamp (MIL) code that illuminates the CHECK ENGINE or SERVICE ENGINE SOON indicator in the instrument cluster The second is a non-emission related non-MIL code that never illuminates the MIL

For emission related MIL codes, the PCM stores the DTC in continuous memory when a fault is detected for the

first time At this point, the DTC does not illuminate the MIL and is now considered a pending code The purpose

of pending codes is to assist in repair verification by reporting a pending DTC after one drive cycle If the same

fault is detected after the next drive cycle, the emission related MIL code illuminates the MIL The MIL remains

on even if the fault is intermittent The MIL is extinguished if the fault is not present through three consecutive

drive cycles or a PCM reset is performed Also, an emission related pending MIL and non-emission related

(non-MIL) code is erased after approximately 40-80 vehicle warm up cycles or a PCM reset

Any scan tool that meets OBDII requirements can access Continuous Memory to retrieve emission related MIL

DTCs However, not all scan tools access pending and non-emission related (non-MIL) DTCs in the same way

Diagnostic Tests

Parameter Identifier (PID) Monitor

Typical WDS DataLogger PID Display

Parameter Identifiers are sensor output values displayed on a scan tool and are chosen based on the vehicle

concern During a guided diagnostic routine, PIDs are accessed that relate to a specific pinpoint test The pinpoint test directs the technician to the specific PID(s) and tells the technician exactly what to look for, or how to

manipulate them

EP2117-A/VF

DIAGNOSTIC PROCESS REVIEW DAY ONE

Diagnostic Tests

WDS Guided Diagnostics

Signal Simulation allows you to substitute a value into the sensor signal wire and monitor PIDs to determine if a

circuit fault exists

For more information select the instruction tab at the bottom of the WDS screen