Emissions Theory and Diagnostics

SECTION 1 Introduction 5-Gas Theory Emissions History OBD II SECTION 2 PCV System Function Failure Diagnosis Emissions Theory and Diagnostics SECTION 3 EGR EGR Theory Vacuum Systems Backpressure Systems DPFE Systems Linear Systems SECTION 4 O 2 Sensors & Fuel Control Performance Testing Heater Testing Fuel Trim Diagnosis SECTION 5 Converters & AIR Injection Converter Theory Efficiency Testing AIR System Theory AIR System Testing SECTION 6 EVAP EVAP Overview Leak Testing Component Testing Efficiency Testing

SECTION 1: INTRODUCTION INTRODUCTION CONTENTS INTRODUCTION The 5 Gases Overview... 1-2 Basic Combustion Chemistry... 1-2 Carbon Dioxide (CO 2 ) & Oxygen (O 2 )... 1-2 Hydrocarbons (HC) & Carbon Monoxide (CO)... 1-3 Oxides of Nitrogen (NO X )... 1-4 Normal Gas Levels... 1-5 Gas Relationships... 1-6 Catalyst Gas Conversion... 1-7 Diagnosing by Gas Failure... 1-8 Emissions Repair Warning... 1-8 History of Emissions Controls Overview... 1-9 PCV Systems... 1-9 EPA Formation... 1-9 EGR Systems... 1-10 High-Energy Ignition Systems... 1-10 Catalytic Converters... 1-11 EPA Timeline... 1-11 Computerized Feedback Fuel Control Systems... 1-11 The 1990 Clean Air Act... 1-12 Alternative Fuels & Service Information Rules... 1-12 Motor Vehicle Owners Right to Repair Act of 2005... 1-12 OBD II Systems OBD II Overview... 1-13 Monitor Trips & Drive Cycles... 1-13 Similar Conditions... 1-14 Continuous & Non-Continuous Monitor Overview... 1-14 Comprehensive Component Monitor (CCM) Explanation... 1-15 Monitor Testing Overlap... 1-15 Drive Cycle Vehicle Preparation Example... 1-16 OBD II Drive Cycle Example... 1-17 Drive Cycle Tips... 1-18 Inspection/Maintenance (I/M) System Check... 1-18 Unmonitored Components, Circuits, & Systems... 1-19 New Monitors... 1-20 Secondary Air Monitor Enhancement... 1-20 PCV Monitor... 1-20 Communication & I/M Problem Vehicles... 1-21 Readiness Monitor Status Anomalies... 1-22 OBD II Serviceability Issues TSB... 1-25 1-1

SECTION 2: PCV PCV CONTENTS POSITIVE CRANKCASE VENTILATION PCV System Construction & Function Positive Crankcase Ventilation (PCV)... 2-1 PCV Operation... 2-1 PCV Failures... 2-2 Daimler Chrysler System Variations PCV Solenoid... 2-2 5.7L Hemi PCV Variations... 2-2 2-1

SECTION 3: EGR EGR CONTENTS EXHAUST GAS RECIRCULATION SYSTEMS Construction & Function EGR Principles... 3-3 Daimler Chrysler EGR Monitor & Codes EGR System Monitor... 3-4 Flow Fault Codes... 3-5 Daimler Chrysler Vacuum EGR Vacuum EGR Valve Introduction... 3-6 Solenoids & Transducers... 3-6 Scan Tool Solenoid PID Test... 3-7 Scan Tool Bi-Directional Controls... 3-7 Lab Scope Solenoid Test... 3-8 Vacuum EGR System Wiring Diagram... 3-9 Daimler Chrysler Linear EGR Linear EGR Valve Introduction... 3-10 Linear EGR Valve Circuits & Operation... 3-10 Lab Scope Linear EGR Valve Test... 3-11 Lab Scope EGR Position Sensor Test... 3-12 Solenoid Circuit Fault Code... 3-13 Position Sensor Fault Codes... 3-13 Linear EGR System Wiring Diagram... 3-13 Ford DPFE EGR EGR System Overview... 3-14 Vacuum Management Overview (Solenoid)... 3-15 Solenoid Resistance Testing... 3-15 Solenoid Scan Tool PIDs... 3-15 Solenoid Lab Scope Test... 3-16 Solenoid Current Test... 3-17 Solenoid Scan Tool & Voltage Test... 3-18 Solenoid Functional Testing... 3-19 Differential (or Delta) Pressure Feedback (DPFE) Sensor... 3-20 DPFE Sampling... 3-21 Common DPFE Faults... 3-21 Trouble Codes EGR Performance... 3-22 Trouble Codes Solenoid... 3-23 Trouble Codes DPFE Sensor... 3-23 Scan Tool DPFE Test Null Value... 3-23 Scan Tool DPFE Test Normal Operation... 3-24 Scan Tool DPFE Test Fault Example... 3-25 Lab Scope EGR Flow Test... 3-26 EGR System Monitor... 3-27 EGR System Wiring Diagram... 3-28 3-1

SECTION 3: EGR EGR CONTENTS EXHAUST GAS RECIRCULATION SYSTEMS General Motors Digital EGR Digital EGR Valve Overview... 3-29 Integrated Electronic EGR Valve Overview... 3-29 Linear EGR Valve Introduction... 3-29 Operating Conditions... 3-30 Linear EGR Valve Circuits & Operation... 3-30 Flow Fault Code... 3-30 Position Fault Codes... 3-31 Control Circuit Fault Code... 3-31 Linear EGR Bi-Directional & DVOM Test... 3-32 Linear EGR Valve & Sensor Test... 3-33 EGR System Monitor... 3-34 EGR System Wiring Diagram... 3-35 3-2

SECTION 4: OXYGEN SENSORS & FUEL CONTROL OXYGEN SENSORS & FUEL CONTROL CONTENTS OXYGEN SENSORS Sensor Construction & Function Sensor Introduction & Identification... 4-3 Sensor Operation... 4-4 Downstream Sensor Fuel Control... 4-4 Sensor Heaters... 4-5 Daimler Chrysler Oxygen Sensors Sensor Circuits & Heater Circuits... 4-6 Sensor Testing Overview... 4-6 Miscalibration Faults... 4-7 Scan Tool Tests... 4-7 Time-To-Activity test... 4-9 Expected HO2S Activity... 4-10 HO2S Signal Hash... 4-11 Slow Response Test... 4-11 HO2S Monitor Upstream... 4-12 HO2S Monitor Downstream... 4-14 Heater Testing Overview... 4-14 Heater Scan Tool Test... 4-14 Heater Bi-Directional Test... 4-15 Heater Voltage Tests JTEC, SBEC, & NGC... 4-17 Heater Diagnostic Pulse Test - NGC... 4-18 HO2S Heater Monitor... 4-19 HO2S Trouble Codes... 4-20 HO2S Heater Control Circuit Trouble Codes... 4-20 HO2S Heater Performance Trouble Codes... 4-21 HO2S Wiring Diagrams... 4-22 Ford Oxygen Sensors Sensor Circuits & Heater Circuits... 4-25 Sensor Testing Overview... 4-25 Time-To-Activity Test... 4-26 Slow Response Test... 4-27 Expected HO2S Activity (Cruise)... 4-27 Sticky Sensor Fault Example... 4-28 HO2S Monitor & Trouble Codes... 4-29 Heater Testing Overview... 4-31 Heater Scan Tool Testing... 4-31 Heater Resistance Testing... 4-31 Heater Circuit Voltage & Current Testing... 4-32 HO2S Heater Monitor & Trouble Codes... 4-33 HO2S Wiring Diagrams... 4-34 4-1

SECTION 4: OXYGEN SENSORS & FUEL CONTROL OXYGEN SENSORS & FUEL CONTROL CONTENTS OXYGEN SENSORS General Motors Oxygen Sensors Sensor Circuits... 4-36 Heater Circuits... 4-36 Sensor Testing Overview... 4-37 Scan Tool Test... 4-37 Time-To-Activity Test... 4-38 Slow Response Test... 4-40 Expected HO2S Activity (Cruise)... 4-41 HO2S Monitor... 4-42 Heater Testing Overview... 4-43 Heater Scan Tool Testing... 4-43 Heater Bi-Directional Testing... 4-43 Heater Voltage Testing... 4-44 HO2S Heater Monitor... 4-44 HO2S Trouble Codes... 4-45 HO2S Heater Trouble Codes... 4-46 HO2S Wiring Diagrams... 4-47 Wide Range Sensor Introduction & Advantages... 4-48 WRAF Circuits... 4-48 WRAF Sensor Operation... 4-49 Scan Tool Testing Lambda... 4-49 Lambda Values... 4-49 WRAF Sensor Diagnosis... 4-50 Fuel Trim Basic Fuel Control... 4-51 Open & Closed Loop... 4-51 General Motors Closed loop Variations... 4-52 Adaptive Fuel Control (Fuel Trim)... 4-52 Fuel Trim Units & Range... 4-53 General Motors Fuel Trim Units... 4-53 Long & Short term Fuel Trim Relationship... 4-53 Fuel Trim & HO2S Relationship... 4-54 Fuel Trim Tables... 4-54 Fuel Trim Reset... 4-56 Diagnosing By Resetting Fuel Trim... 4-57 Daimler Chrysler, Ford, & GM Scan Tool Tests... 4-57 Simplified Fuel Trim Monitor Explanation... 4-60 Fuel Trim Monitor Daimler Chrysler, Ford, & General Motors... 4-61 Fuel Trim Trouble Codes... 4-61 4-2

SECTION 5: CONVERTERS & AIR INJECTION CONVERTERS & AIR INJECTION CONTENTS CATALYTIC CONVERTERS Construction & Function The Need for Catalysts & Catalyst Types... 5-2 Catalyst Operating Temperatures... 5-3 Catalyst Failures & Air Injection Reaction Systems... 5-3 Converter Chemistry... 5-4 Catalyst Effectiveness & Catalyst Monitor Logic... 5-5 Daimler Chrysler Monitor Conditions SBEC, JTEC, & NGC... 5-6 Catalyst Monitors... 5-6 Catalyst Efficiency Trouble Codes... 5-7 Ford Motor Company Converter Efficiency Monitor & Switch Ratio Method... 5-8 Switch Ratio Driving Pattern... 5-9 Index Ratio Method & General Catalyst Monitor Operation... 5-9 Trouble Codes... 5-10 General Motors Converter Efficiency Monitor... 5-11 Converter Efficiency Monitor Logic... 5-12 Catalyst Efficiency Trouble Codes... 5-12 Catalyst Efficiency Testing Catalyst Testing Overview & Rattle Test... 5-13 Exhaust Backpressure & Catalyst Temperature Tests... 5-14 Gas Analyzer Test Before & After and Cranking HC... 5-15 Catalyst Scan Tool Test... 5-16 AIR PUMPS Air Injection Overview General Operating Modes & Belt Driven Systems... 5-18 Belt Driven System Wiring Example... 5-19 Ford Electric Air Pumps Electric Air Pump Overview & Operation... 5-20 Bypass Solenoids & System Scan Tool Testing... 5-21 Electric Air Pump Fault Example... 5-22 Air Pump Current Test... 5-23 Secondary Air Monitor & Trouble Codes... 5-24 Electric Pump System Wiring Diagram... 5-26 General Motors Electric Air Pumps Air Injection Overview... 5-27 Air Injection Components... 5-28 System Disabling Conditions... 5-28 AIR System Diagnosis & Bi-Directional Test... 5-29 Air Pump Current Test & System Trouble Codes... 5-30 5-1

SECTION 6: EVAP SYSTEMS EVAP SYSTEMS CONTENTS EVAPORATIVE EMISSIONS SYSTEMS Construction & Function The Hydrocarbon Problem... 6-5 EVAP System Overview... 6-5 EVAP System Components... 6-6 Charcoal Canister... 6-6 System Vapor Flow... 6-7 Canister Vapor Flow... 6-8 Canister Failures... 6-8 Purge Solenoid... 6-9 Solenoid Faults... 6-9 Solenoid Controls... 6-9 EVAP System Test Port & Vent Solenoid... 6-10 Daimler Chrysler Typical EVAP System Graphics... 6-11 Purge Solenoid Trouble Codes... 6-12 Proportional Purge Solenoid Purge Sense... 6-12 Scan Tool Purge Solenoid Test... 6-12 Scan Tool Bi-Directional Tests KOEO... 6-14 Scan Tool Bi-Directional Tests KOER... 6-14 DVOM/GMM Purge Solenoid Test... 6-15 Lab Scope Purge Solenoid Test Conventional... 6-16 Purge Solenoid Current Test Conventional... 6-17 Lab Scope Purge Sense Test Proportional... 6-17 Lab Scope Purge Solenoid Test Proportional... 6-18 Onboard Refueling Vapor Recovery (ORVR)... 6-19 EVAP Monitor Overview... 6-20 Purge Flow Monitor Conditions SBEC... 6-20 Purge Flow Monitor Conditions JTEC... 6-20 Purge Flow Monitor Conditions NGC... 6-20 Purge Flow Monitor Process... 6-21 Leak Detection Pump System Introduction... 6-21 EVAP System Leak & Performance Codes LDP... 6-22 LDP Solenoid Trouble Codes... 6-22 LDP Switch Trouble Codes... 6-22 LDP EVAP Monitor Differences... 6-22 LDP Monitor Explanation... 6-23 LDP Pump Mode... 6-23 LDP Test Mode... 6-23 Missing/Loose Gas Cap... 6-24 6-1

SECTION 6: EVAP SYSTEMS EVAP SYSTEMS CONTENTS EVAPORATIVE EMISSIONS SYSTEMS Daimler Chrysler - Continued LDP System TSB... 6-24 Scan Tool Bi-Directional Tests LDP EVAP Monitor... 6-25 Lab Scope Test LDP Solenoid... 6-26 Lab Scope Test LDP Monitor... 6-26 Natural Vacuum Leak Detection (NVLD) Overview... 6-27 NVLD Components... 6-27 NVLD Solenoid... 6-27 EVAP System Leak & Performance Codes NVLD... 6-28 NVLD Component Trouble Codes... 6-28 NVLD Rationality & Flow Check... 6-29 NVLD Small Leak Test... 6-29 NVLD Medium & Large Leak Test... 6-30 NVLD Switch Trouble Codes... 6-30 NVLD Scan Tool PID Test... 6-31 NVLD Solenoid Current Testing... 6-31 Lab Scope NVLD Solenoid Test... 6-32 EVAP System Wiring Diagrams... 6-33 Ford Motor Company Ford-Specific Component Overview... 6-37 System Vapor Flow... 6-38 Vent Solenoid Trouble Codes... 6-38 Vent Solenoid Scan Tool PID Test... 6-39 Vent Solenoid Scan Tool Bi-Directional Test... 6-39 Vent Solenoid Resistance Test... 6-40 Purge Solenoid/Vapor Management Valve... 6-41 Purge Solenoid/VMV Trouble Codes... 6-42 Purge Solenoid/VMV Resistance Test... 6-42 Purge Solenoid/VMV Scan Tool Test... 6-43 Lab Scope Purge/VMV Solenoid Test... 6-44 Purge Solenoid/VMV Current Test... 6-45 Purge Flow Sensor & Sensor Testing... 6-46 Fuel Tank Pressure Sensor... 6-47 Pressure Sensor Calibration... 6-48 Fuel Tank Pressure Sensor Trouble Codes... 6-48 Pressure Sensor Scan Tool Test... 6-49 Onboard Refueling Vapor Recovery (ORVR)... 6-49 EVAP Monitor Drive Cycle... 6-50 6-2

SECTION 6: EVAP SYSTEMS EVAP SYSTEMS CONTENTS EVAPORATIVE EMISSIONS SYSTEMS Ford Motor Company - Continued EVAP Monitor Process... 6-51 Monitor Trouble Codes... 6-51 EVAP Monitor Some Late Model... 6-52 Late Monitor Type Overview... 6-52 0.020 Leak Check Overview... 6-53 Monitor Enabling Conditions... 6-53 Monitor Abort Conditions For Phase 2... 6-54 Phase 0: Vacuum Build... 6-54 Phase 1 & 2: Vacuum Stabilization & Vacuum Hold & Decay... 6-55 Phase 3 & 4: Vacuum Release & Vapor Generation... 6-56 Idle Check... 6-56 Late Monitor Trouble Codes & Fail Thresholds... 6-57 Engine Off Natural Vacuum (EONV) Leak Check... 6-57 EONV Phases... 6-58 EONV Trouble Codes... 6-59 Monitor Scan Tool Trick... 6-59 EVAP System Wiring Diagrams... 6-60 General Motors Enhanced EVAP System Implementation & System Vapor Flow... 6-63 Typical EVAP System Graphic... 6-64 Charcoal Canister... 6-64 Canister Vapor Flow... 6-65 Vent Solenoid... 6-66 Vent Solenoid Trouble Codes... 6-67 Purge Solenoid... 6-67 EVAP System Test Port... 6-68 Purge Solenoid Trouble Codes... 6-68 Scan Tool Test - Vent & Purge Solenoids... 6-69 Scan Tool Bi-Directional Tests... 6-70 Combination Testing... 6-70 Scan Tool Service Bay Test... 6-71 Vent Solenoid Lab Scope & Current Test... 6-72 Purge Solenoid DVOM Test... 6-72 Purge Solenoid Lab Scope Test... 6-73 Fuel Tank Pressure Sensor... 6-74 Fuel Tank Pressure Sensor Trouble Codes... 6-75 FTP Sensor Scan Tool Test... 6-75 6-3

SECTION 6: EVAP SYSTEMS EVAP SYSTEMS CONTENTS EVAPORATIVE EMISSIONS SYSTEMS General Motors - Continued FTP Sensor Bi-Directional Test... 6-76 Onboard Refueling Vapor Recovery (ORVR)... 6-76 EVAP Monitor Drive Cycle... 6-77 EVAP Monitor Process & Check Gas Cap Message... 6-78 Engine Off Natural Vacuum (EONV) Leak Check... 6-79 EONV Stages... 6-79 EONV Enabling Conditions... 6-80 EONV Volatility Test... 6-80 EONV Pressure Test... 6-80 EONV Vacuum Test... 6-81 EONV Test Results... 6-81 Scan Tool Testing Tip... 6-81 EVAP System Wiring Diagram... 6-82 6-4