OBD II UPDATE TRAINING COURSE OBD II Module

OBD II UPDATE TRAINING COURSE

OBD II Module Outline • • • OBD II Foundation OBD II History OBD II Terminology OBD I vs OBD II MIL Operation • DTCs (A & B types • • • OBD II Numbering Rationality / Normality One/Two Trip DTCs Freeze Frame I/M Readiness Monitors

SESSION 1 OBD I FOUNDATION • Onboard Diagnostics Generation 2 – Not a stand alone system – OBD II is built on top of OBD I

THE OBD I FOUNDATION • OBD I mandated a “Check Engine Light” • Included diagnostic trouble codes (DTCs)

THE OBD I FOUNDATION • OBD I Mandated in 1988 • Objectives – Improve emission compliance by notifying the driver that there was a malfunction – Assist in identifying malfunctioning circuits in the computer control system

OBD I MIL Operation • Check Engine Light Operation – Illuminated when circuit was abnormal • Open, Shorted, Grounded – Illuminated intermittently when circuit operated abnormally intermittently – Didn’t always illuminate when a problem was detected! – WAS INCONSISTENT!!!

Serial Data • Live Computer Data – Supplied by the vehicle’s computer – Read via a Scan Tool – Interpreted Data – GM, Chrysler, then Ford – Now mandated by OBD II

Diagnosing Today’s Vehicles • Technician must have a strong foundation in system operation & theory!!! • Technician must have ability to fully utilize today’s tools – Scan Tool, DSO, 5 -gas analyzer, etc. • Technician must know how theory & tools are best applied together

OBD I • On Board Diagnostics with a Check Engine Light • Mandated by CARB • Gave birth to OBD II

OBD II Update Training Course Session II OBD II Foundation

Session 1 The OBD I Foundation • OBD I - On Board Diagnostics with a Check Engine Light – MIL Operation Inconsistent – DTC Viewing Method Inconsistent – DTC Criteria Inconsistent – DTC Numbering Inconsistent

The OBD II System • The Second Generation was designed to fix the inadequacies of the First Generation • One of the biggest problems was the system must be monitored under load!

OBD I Mode Monitoring • Degraded emission systems did not set Check Engine Light • EVAP, CAT, & AIR were not monitored • O 2 S Performance not monitored • CAT killing misfires not monitored • Shifted air fuel ratios not monitored • NOx emissions not monitored (still? )

OBD II Strategies • Implementation slated for 1996 models • Phase in to begin 1994 -1996 • OEMs allowed to EEPROM flash to lock-out problems affecting CSI – Check with manufacturer regarding current configuration

Setting the Standards • C. A. R. B - 1994 - 1998 • E. P. A. 1998 - On • S. A. E. – Requirements for common systems – Programming changes

OBD II Requirements • Must be installed on all vehicles • Must be able to determine operating condition of the vehicle’s emission control system / strategy • Diagnostics & Functions must be standardized

OBD II Requirements • PCM must store DTCs for detected faults • DTC’s must stay in memory until cleared following repair or until 40 consecutive warm-up cycles – 80 consecutive warm-up cycles if misfire and/or fuel control related

OBD II Requirements • The system must test emission control systems, record the results, and display those results • A MIL is mandatory – must illuminate when a fault is detected (and confirmed? ) – must remain illuminated until the fault is corrected (3 tests)

OBD II Requirements • Generic Scan Tool (GST) • SAE J 1850 and/or ISO 9141 communication protocol • Must monitor ALL OBD II information • Monitoring & DTC clearing procedures must meet CARB & EPA standards • Must display Parameter ID (PIDs) • Freeze Frame Data • PCM Parameters & Test Results

OBD II Requirements • Monitor Test Results • Comprehensive Component Monitoring – Input Normality & Rationality – Outputs for performance or at least electrically

The Scan Tool (2 Tools In One? ) • OBD II Generic Scan Tool (GST) • Manufacturer Specific Scan Tool • Hybrid – OBD II Generic with Manufacturer Specific Capabilities

OBD II Commonalties • • • Standardization Facilitated by SAE compromised of Reps from OEMs OBD II guidelines established by SAE OEMs interpreted guidelines differently OBD II is the SAME, but DIFFERENT!

Emission Related Monitoring • Unlike OBD I, OBD II not only monitors an actuator was commanded on, but tests the system to make sure it actually worked!!!

OBD II Monitors • Designed to detect failures that would cause emissions to increase by 50% or would shorten the life of the catalytic converter • The number of monitors are increasing • Monitors require more computing resources and additional sensors • Monitors are run under specific conditions

OBD II Program Management • • Program Manager Task Manager Diagnostic Executive OBD II Program Management – Artificial Intelligence – Rationality

OBD II Standardization • Common Diagnostic Connector – Data Link Connector (DLC) – 16 pins -- 7 for SAE/OBD II & 9 for OEM – 1 pin is B+ to power Scan Tool – DLC to be located on drivers side near steering column or have a location label

MIL Regulations • MIL will illuminate when an increase in emissions = to 1. 5 X the FTP is inferred • Or when the PCM/Network itself malfunctions • The MIL shall not be used for any other purpose!!!

MIL Operation • MIL On – a fault has been detected (and confirmed? ) • MIL Off – No fault has been detected – Test have not been run • MIL Flashing – Catalyst damaging misfire or air fuel problem detected

Diagnostic Trouble Codes • Common numbering system for all DTCs – Alpha Numeric – 5 digit • DTCs must be similar in meaning • DTC designation must be common • SAE standard J 2012

DTC Numbering • 1 st Digit – Alpha Character – “P” - Powertrain – “C” - Chassis – “B” - Body – “U” - Uart / multiplexing / networking

DTC Numbering • 2 nd Digit or thousandth position • Either “ 1” or “ 0” • “ 0” Codes are SAE / OBD II Controlled • “ 1” Codes are Manufacturer Specific

DTC Numbering • • 3 rd Digit or hundredth position System Fault “ 100” - Fuel & Air Metering “ 200” - Fuel & Air Metering (injector & fuel pump) • “ 300” - Misfire or Ignition System • “ 400” - Emission Control

DTC Numbering • • • 3 rd Digit or hundredth position System Fault “ 500” - Vehicle Speed and/or Idle Control “ 600” - Computer Output Circuits “ 700” - Transmission “ 800” - Transmission

DTC Numbering • 4 th & 5 th Digits - tens & ones • Designate Specific Fault • Example – P 0301 = Engine Cylinder # 1 Misfire Detected

Diagnostic Trouble Codes OBD I vs. OBD II 1. OBD II requires “code enabling criteria” be met (maybe twice) before a code is stored. OBD I only needed abnormality 2. OBD II for emissions ONLY! OBD I is not. Most OEMs recommend fixing OBD I first - before checking / repairing OBD II

Diagnostic Trouble Codes OBD I vs. OBD II • OBD I diagnostic procedure was to… – Pull Codes – Record Codes – Erase Codes – Operate Vehicle – Pull Codes • Erasing OBD II Codes will also erase Freeze Frame Data

Diagnostic Trouble Codes OBD I vs. OBD II • OBD II has no “soft codes” • OBD II diagnostic procedure – Pull Code – Record Freeze Frame Data – Repair Root Cause – Operate vehicle at Freeze Frame parameters – Meet code enable criteria – Run monitor

MULTIPLEXING • Vehicles use multiple onboard computers • Faults in other computers can disable monitors due to multiplexing • Example – Wheel Speed Sensors used to verify rough road to prevent false misfire codes

Code Enable Criteria • Definition – “Once the conditions are met to test for the DTC are met, then the monitor will run the test” • P 0134 - HO 2 S - 11 Remains At Center (B 1 S 1) Code Conditions: – Engine runtime over 2 minutes, ECT sensor input more than 176 degrees F, then the test started and the PCM detected that the front HO 2 S-11 signal was 0. 5 v (fixed at mid-range for 1 minute)

ONE TRIP DTCs • MIL will illuminate after one DTC enable criteria has been met and failed! • Most common One Trip failures are… – Misfire & Fuel Control Monitors – CCM will depending on manufacturer • TPS, MAP, MAF, ECT, CKP, etc.

TWO/THREE TRIP DTCs • MIL will illuminate when DTC enable criteria are met and failed in 2 consecutive trips • Compromise for CSI • DTC confirmation

TWO/THREE TRIP DTCs • When 1 st trip fails – Code is “pending” or “maturing” – Freeze Frame data is captured, but not displayed – MIL is off

TWO/THREE TRIP DTCs • If & When 2 nd trip fails… – MIL is illuminated – Code “matures” & DTC is set – Freeze Frame Data can be viewed • Same with 3 trip failures… – Except add 1 trip

PENDING DTCs • If 2 nd trip passes (doesn’t fail)… – Pending Code stays pending for 40 good trips or 80 good trips for misfire / air fuel – Freeze Frame Data is displayed – MIL stays off

MIL Strategies & DTCs First Trip Failure • • • MIL Command: MIL “bad trip” counter: MIL “good trips”: DTC Command: DTC “bad trips”: DTC “good trips” Pending DTC: Pending “good trips”: Freeze Frame Data: • • • Off One “bad trip” N/A Set, but not displayed

MIL Strategy Exercise

MIL Strategies & DTCs 2 nd Consecutive Trip Failure • • • MIL Command: MIL “bad trip” counter: MIL “good trips”: DTC Command: DTC “bad trips”: DTC “good trips”: Pending DTC: Pending “good trips”: Freeze Frame Data: • • • On Reset to zero N/A Set & Displayed Reset to zero N/A Set or cleared N/A Displayed

MIL Strategies & DTCs 2 nd Consecutive Trip Pass • • • MIL Command: MIL “bad trip” counter: MIL “good trips”: DTC Command: DTC “bad trips”: DTC “good trips”: Pending DTC: Pending “good trips”: Freeze Frame Data: • • • Off Reset to zero N/A Set or cleared One “good trip” Displayed or not

MIL Strategies & DTCs Fault Repaired / DTC Not Cleared • • • MIL Command: MIL “bad trip” counter: MIL “good trips”: DTC Command: DTC “bad trips”: DTC “good trips”: Pending DTC: Pending “good trips”: Freeze Frame Data: • • • On Reset to zero N/A Set & displayed Reset to zero N/A Set or cleared N/A Displayed

DTC Priority Designation • Type “A” DTCs – Usually “One Trip” codes – CAT Damaging or 1. 5 X FTP • Type “B” DTCs – Usually “ 2 or 3 Trip” codes – Serious failure • Type “C” & “D” DTCs – Not emission related / won’t illuminate MIL

DTC Clearing • Automatic Code Clearing – After 40 warm-up cycles with no re-occurrence – Or – After 80 warm-up cycles with no re-occurrence for misfire or fuel control codes – Freeze Frame Data gets erased as well • Manual Code Clearing – Through Scan Tool or battery disconnect

Common Terminology & Vocabulary • Vernacular Standardization / “New Speak” • Standardization of Terms – ALDL - DLC – EGO - O 2 S or HO 2 S – MAT - IAT – Integrator/Block Learn - STFT/LTFT – ESS - CKP

FREEZE FRAME DATA • The exact second of data that set the DTC • Mandated Data – Calculated Engine Load – Engine Coolant Temperature – Loop Status (open or closed) – STFT / LTFT – Vehicle Speed (mph) – Engine Speed (rpm) – DTC set

FREEZE FRAME DATA • Freeze Frame Data – 1 st failed trip of 1 st DTC – Not overridden by subsequent DTCs – UNLESS! – Subsequent DTCs are of a higher priority – “A” Type Codes (misfires & fuel control) or a higher priority than “B” Type Codes.

DTC / Freeze Frame Exercise

OBD II Diagnostics • Scan Tool Enhancements – Expanded Information - manufacturer specific – Expanded Description • Troubleshooter - Pathfinder – Identification of Responding PCM • VIN - CAL ID – Vehicle Preparation • Warm-ups, Trips, Drive-cycles

OBD II Diagnostics • Scan Tool Enhancements (cont’d) – Diagnostic Procedures • Troubleshooter - Pathfinder – Repair Verification • Reset, relearn, adaptive strategies – PID Description & Values • sensor specifications – Test Procedures • Actuators • Miscellaneous

OBD II Diagnostics • Scan Tool Enhancements (cont’d) – DTC Library • code description & enable criteria – O 2 S location & type – Sensor Simulator – EEPROM Flashing – Replacement PCM Programming

OBD II Update Training Course Session II OBD II Foundation

Session 1 The OBD I Foundation • OBD I - On Board Diagnostics with a Check Engine Light – MIL Operation Inconsistent – DTC Viewing Method Inconsistent – DTC Criteria Inconsistent – DTC Numbering Inconsistent

The OBD II System • The Second Generation was designed to fix the inadequacies of the First Generation • One of the biggest problems was the system must be monitored under load!

OBD I Mode Monitoring • Degraded emission systems did not set Check Engine Light • EVAP, CAT, & AIR were not monitored • O 2 S Performance not monitored • CAT killing misfires not monitored • Shifted air fuel ratios not monitored • NOx emissions not monitored (still? )

OBD II Strategies • Implementation slated for 1996 models • Phase in to begin 1994 -1996 • OEMs allowed to EEPROM flash to lock-out problems affecting CSI – Check with manufacturer regarding current configuration

Setting the Standards • C. A. R. B - 1994 - 1998 • E. P. A. 1998 - On • S. A. E. – Requirements for common systems – Programming changes

OBD II Requirements • Must be installed on all vehicles • Must be able to determine operating condition of the vehicle’s emission control system / strategy • Diagnostics & Functions must be standardized

OBD II Requirements • PCM must store DTCs for detected faults • DTC’s must stay in memory until cleared following repair or until 40 consecutive warm-up cycles – 80 consecutive warm-up cycles if misfire and/or fuel control related

OBD II Requirements • The system must test emission control systems, record the results, and display those results • A MIL is mandatory – must illuminate when a fault is detected (and confirmed? ) – must remain illuminated until the fault is corrected (3 tests)

OBD II Requirements • Generic Scan Tool (GST) • SAE J 1850 and/or ISO 9141 communication protocol • Must monitor ALL OBD II information • Monitoring & DTC clearing procedures must meet CARB & EPA standards • Must display Parameter ID (PIDs) • Freeze Frame Data • PCM Parameters & Test Results

OBD II Requirements • Monitor Test Results • Comprehensive Component Monitoring – Input Normality & Rationality – Outputs for performance or at least electrically

The Scan Tool (2 Tools In One? ) • OBD II Generic Scan Tool (GST) • Manufacturer Specific Scan Tool • Hybrid – OBD II Generic with Manufacturer Specific Capabilities

OBD II Commonalties • • • Standardization Facilitated by SAE compromised of Reps from OEMs OBD II guidelines established by SAE OEMs interpreted guidelines differently OBD II is the SAME, but DIFFERENT!

Emission Related Monitoring • Unlike OBD I, OBD II not only monitors an actuator was commanded on, but tests the system to make sure it actually worked!!!

OBD II Monitors • Designed to detect failures that would cause emissions to increase by 50% or would shorten the life of the catalytic converter • The number of monitors are increasing • Monitors require more computing resources and additional sensors • Monitors are run under specific conditions

OBD II TRAINING MODULE OBD II MAIN MONITORS

READINESS FLAGS • Definition – Tells you via Scan Tool if monitor has been completed • Done, Ready, Readiness Test Complete – Does not tell you the outcome!!! • If pass once or twice - no code • If fail once or twice - DTC

SYMPTOM WITHOUT CODES • Run 2 or 3 drive cycles… • Check for DTCs & Pending DTCs • If no OBD II problems detected then… – Check mechanical, electrical, ignition, emissions, fuel, and any other non computer monitored system

OBD II “TRIPS” • Definition… – A set of operating conditions to be met in order to run a monitor so that the test is valid and drive-ability is not sacrificed. • Purpose / Objectives – To test a component or system – To verify complaint – To verify repair effectiveness

OBD II “DRIVE CYCLES” • Definition… – A specific set of operating conditions that enable ALL “trips” to complete and ALL monitors to run

OBD II “WARM-UP CYCLES” • Definition… – ECT must begin below and rise above 160° F – ECT must rise at least 40° F – No further faults occur – Sometimes includes CTS and BTS (IAT) be within 10° F of each other • Purpose / Objectives – Erase DTCs & Freeze Frame – Enable criteria for some DTCs & Trips

FUEL LEVEL INPUT • Fuel Level should be between… – 15% & 85% – 25% & 75% • If not… – Some Monitors will not run! • For Example… – EGR, EVAP Leak, EVAP Flow, & Fuel System need fuel level above 15%

OBD II Monitors • Comprehensive Component Monitor • Catalyst Efficiency Monitor • Misfire Monitor • EGR Monitor • EVAP Monitors • Fuel System Monitor • Oxygen Sensor Monitors • Secondary Air Monitor

COMPREHENSIVE COMPONENT MONITOR • Definition… – A continuous look at a lot of something • Sensors - VSS, CKP, KS, TPS, CTS, CMP • Outputs - Any and all outputs that could affect emissions • Checks for “Normality” constantly • Checks for “Rationality” when enable criteria is reached

COMPREHENSIVE COMPONENT MONITOR • All “Rationality” checks should be performed in the course of a “Drive Cycle” • DTCs could be 1 or 2 trip codes

CATALYST EFFICIENCY MONITOR • Infers Catalyst efficiency by comparing pre & post O 2 S operation • A working oxidation consumes O 2 in order to oxidize HC & CO into Water & CO 2 • A working catalyst uses Cerium that stores and releases O 2 to enhance efficiency

CATALYST EFFICIENCY MONITOR • Upstream O 2 S should oscillate • Downstream activity should not be within 70% of Upstream • Generic Enable Criteria is as follows: – ECT >170°, Closed Loop for at least 3 minutes, RPM between 1, 200 & 2, 500, Vehicle Speed at least 20 mph for 3 minutes, MAP between 11” 15” hg, and fuel level over 15%

CATALYST EFFICIENCY MONITOR • DTC - P 0420 – Set when monitor is run and fails – Might be due to defective catalyst – Could be caused by O 2 S performance, ECT too low, exhaust leak, etc… • This monitor doesn’t check the reduction portion of the catalyst • The upstream & downstream O 2 Ss are NOT the same!!!

MISFIRE MONITOR • Misfires result in HC failures • Misfires damage catalysts • Two types of misfires – “A” & “B” misfires – “A” identifying SEVERE misfires – Type “A” misfires might result in MIL flashing

MISFIRE DETECTION • Relies on CKP Sensor • Usually Variable Reluctor • PCM looks for asymmetrical signal – either frequency or amplitude • Some vehicles use Hall-Effect • Some vehicles use a totally separate sensor

MULTIPLE MISFIRES • DTC - P 0300 – Random / Multiple Misfire Detected • Usually the cylinder that is misfiring is identified by the code • Depending on the % of time a cylinder is misfiring it will be designated “A” or “B” • Remember - A type “A” misfire will overwrite previous Freeze Frame Data!

MISFIRE MONITORS “ROUGH ROAD” • Vibration due to rough roads could result in false P 0300 DTCs • Some manufacturers refer to wheel speed sensors to verify rough road conditions • If rough road is verified - misfire monitor is suspended. • Faulty wheel speed sensor circuits can prevent misfire monitor • Check OBD I codes first!!!

MISFIRE MONITOR DIAGNOSIS • OBD II Misfire Monitor can be more sensitive than an ignition oscilloscope! • Verify misfire with DSO connected to… – CKP or Misfire Sensor and map signal when MIL illuminates – Upstream O 2 S and map signal within 10% of Freeze Frame Data • O 2 S won’t tell you which cylinder - just that a misfire is occurring.

EGR MONITOR • EPA Requirement for monitoring EGR system… – The diagnostic system shall monitor the EGR system on vehicles so equipped for low & high flow rate malfunctions. • Monitoring Alternatives – MAP, O 2 S, Temperature

EGR MONITOR MAP • Manifold Pressure is monitored during EGR system operation to determine flow rate – Usually on deceleration • Monitoring Performed by Pressure Differential Sensor – Same as MAP, but with different name • Lower than expected pressure infers low flow rate. Higher than expected pressure infers excessively high flow rate.

EGR MONITOR OXYGEN SENSOR TEST • Energizing EGR system removes O 2 from combustion chamber • De-energizing EGR system increases O 2 in combustion chamber • PCM monitors how long it takes fuel trim to put O 2 back on track to measure flow rate

EGR MONITOR TEMPERATURE SENSING • Sensor installed in EGR passage • PCM determines EGR flow rate by monitoring temperature

EGR MONITOR ENABLE CRITERIA • Varies from manufacturer to manufacturer • Typical enable criteria as follows: – Closed Loop – Steady cruise (40 -55 mph) for three minutes – Deceleration from steady cruise (no braking) – No other DTCs associated with EGR or monitoring system • Usually 2 trip DTC

EVAP MONITOR • EPA Requirements for monitoring EVAP system… – The diagnostic system shall verify air flow from the complete system. In addition, the diagnostic system shall also monitor the evaporative system for the loss of HC vapor into the atmosphere by performing a pressure or vacuum check of the complete evaporative system. Manufacturers may temporarily disable the evaporative purge system to perform a check.

EVAP MONITOR • Malfunction Criteria – No purge is occurring – A leak = or > 0. 040” (0. 020” in the future) • MIL Illumination and DTC storage – Usually a 2 trip code • Remember! – Fuel tank must be between 15% & 85% (25% & 75%)

EVAP MONITOR • Purpose of EVAP system – To store HCs that would have otherwise evaporated into the atmosphere and purge them into the induction system for burning. – A leak = 0. 020” will allow 1. 35 grams of HCs into the atmosphere for every mile traveled!

EVAP MONITOR • All EVAP Monitors require a warm-up cycle! EVAP tested once per drive cycle! • OBD II uses 1 or 2 EVAP system vent solenoids (isolate system) • Differential Pressure Sensors (EGR Monitor? ) – reads pressure in inches of water. 1 inch =. 25” of mercury (HG)

EVAP MONITOR • 2 Methods of testing the system for integrity –Vacuum testing –Pressure Testing

EVAP MONITOR • Vacuum Testing –Seal the system –Pull a vacuum –Monitor the Differential Pressure Sensor over time

EVAP MONITOR • Pressure Testing – Seal the system – Pump up a pressure – Monitor Differential Pressure Sensor over time • More accurate than Vacuum Testing because vacuum can sometimes temporarily seal a small leak.

EVAP MONITOR • Code Enable Criteria – Varies manufacturer to manufacturer – One manufacturer’s criteria is as follows: • • • Fuel tank level is between 15% & 85% Engine off (soak) time 6 hours minimum Time since start-up between 330 & 1800 seconds IAT between 40° & 100° F BARO (<8, 000 ft. altitude), minimum 22. 5” HG

EVAP MONITOR • Code Enable Criteria (cont’d) – Engine Load between 20% & 70% – VSS between 40 & 75 mph – Purge duty cycle between 75% & 100% – Fuel tank pressure between 1. 7” & 2. 5” H 2 O

EVAP MONITOR • Usual DTC’s – P 0450 - Evaporative Emission Control System Vent Valve/Solenoid Circuit Malfunction – P 0455 - Evaporative Emission Control System Leak Detected (Gross Leak) – P 0442 - Evaporative Emission Control System Leak Detected (Small Leak)

EVAP MONITOR FAILURE DIAGNOSIS • Scan Tool EVAP Test – Manufacturers Scan Tool ability – Scan Tool can operate vent solenoids to seal the system – Scan Tool can cycle purge solenoid to pull a vacuum on system and then seal it off – Scan Tool will monitor Differential Pressure Sensor to determine if a leak exists and if it is large or small

EVAP MONITOR FAILURE DIAGNOSTICS • Smoke Machine EVAP Testing – Use Scan Tool and seal the system – Open EVAP system and introduce smoke or use schrader adapter (green cap) – CAUTION - watch the pressure!!! – Watch for escaping smoke

EVAP MONITOR FAILURE DIAGNOSIS • Dedicated Tester – Pressure pump with gauge that reads inches of water (not mercury) – Doesn’t help in isolating the leak just verifies there is a leak

EVAP MONITOR FAILURE DIAGNOSIS • Gas Analyzer Testing – Isolate / Seal the system as necessary – Pressurize the system – Use gas analyzer as you would a halogen leak detector for AC work • Gas Cap Testers

FUEL SYSTEM MONITOR • EPA requirements for monitoring Fuel System… – The diagnostic system shall monitor the fuel delivery system for its ability to provide compliance with emissions standards

FUEL SYSTEM MONITOR • Continuously monitored whenever ignition is on! • Usually type “A” DTCs (one trip) • Relies on fuel trim data directly and O 2 S data indirectly

FUEL SYSTEM MONITOR • OBD I Terms – Carburetor Dwell – Duty Cycle – Voltage – Integrator / Block Learn

FUEL SYSTEM MONITOR • Fuel Trim – Short Term – Long Term • Values – + % #s mean fuel is being added over base calculations – - % #x mean fuel is being subtracted over base calculations – usually + or - 10% is acceptable

OXYGEN SENSOR MONITOR • EPA Requirements for monitoring the Oxygen Sensor… – The diagnostic system shall monitor the output voltage, response rate, and any other parameter which can effect emissions, of all primary (fuel control) oxygen (lambda) sensors for malfunction. It shall also monitor all secondary oxygen sensors (fuel trim control or use as a monitoring device) for proper output voltage and/or response rate

OXYGEN SENSOR MONITOR • EPA Requirements for monitoring the Oxygen Sensor (cont’d)… – Response rate is the time required for the oxygen sensor to switch from lean to rich once it is exposed to a richer than stoichiometric exhaust gas or vice versa (measuring oxygen sensor switching frequency may not be an adequate indicator of oxygen sensor response rate, particularly at low speeds)

OXYGEN SENSOR MONITOR • EPA Requirements for monitoring the Oxygen Sensor (cont’d)… – For vehicles equipped with heated oxygen sensors, the heater circuit shall be monitored for proper current and voltage drop (note: a continuity check of oxygen sensors is not required)

O 2 S MONITORING • 3 TESTS ARE PERFORMED… – First test is for calibration. • Is the sensor operating between allowable tolerances? – Second test is switching time. • How long does it take to go from rich to lean or vice versa? – Third test is frequency • O 2 S activity under normal (? ) conditions

SECONDARY AIR MONITORING • EPA Requirements for monitoring Secondary Air operation – Any vehicle equipped with any form of secondary air delivery system shall have the diagnostic system monitor the proper functioning of the secondary air delivery system and any air switching valve.

SECONDARY AIR MONITORING • Two Common Tests… – 1. Widen injector pulse width for a artificially rich condition & monitor O 2 S. Pump Secondary Air upstream and monitor O 2 S – 2. Monitor STFT / LTFT and pump Secondary Air upstream

OBD II UPDATE TRAINING Round-Up

MALFUNCTION INDICATOR LIGHT (MIL) • MIL Status – Off • PCM has not detected any faults in an emission related component or system, or MIL is inop – On Steady • indicates a fault in an emissions related component or system that could affect emission levels – Flashing • misfire or fuel control system fault that could damage catalytic converter

MALFUNCTION INDICATOR LIGHT (MIL) • Turning Off the MIL – Codes are cleared through scan tool – Power to PCM is removed • disconnect battery • remove fuse(s) • doesn’t always work – 3 consecutive trips are completed without further faults detected

SIMILAR CONDITIONS FUEL & MISFIRE • Engine RPM within 375 of stored Freeze Frame Data • Engine Load within + or - 10% of stored Freeze Frame Data • Engine Coolant Temperature similar to stored Freeze Frame Data

DIAGNOSTIC TROUBLE CODES (DTCs) • 5 Digit - Alpha-numeric DTCs – First Digit (reading from left to right) • Designates either powertrain (P), Body (B), Chassis (C), or Network (U) – Second Digit • Designates DTC as SAE Generic (0) or Manufacturer Specific (1)

DIAGNOSTIC TROUBLE CODES (DTCs) – Third Digit • Designates Faulted System – – – – 1 -Air Metering & Fuel System 2 -Fuel System (fuel injector only) 3 -Ignition System or Misfire 4 -Emission Control System 5 -Idle Speed / Vehicle Speed 6 -Computer Outputs 7&8 -Transmission & Transaxles – Fourth & Fifth Digits • Designates Specific Fault

DIAGNOSTIC TROUBLE CODES (DTCs) • DTC Types – “A” - One trip codes – “B” - All Other • DTC Erasure – Scan Tool – Removing Power from PCM (sometimes) – Automatic after 40 warm-up cycles with no further faults detected or 80 warm-up cycles for misfire & fuel system

FREEZE FRAME DATA • Definition - a single frame of data that displays at a minimum the following data: – – – – Calculated Engine Load (%) Engine Coolant Temperature (ECT) Fuel System Status (OL or CL) Short Term Fuel Trim (STFT) Long Term Fuel Trim (LTFT) Miles Per Hour (MPH) Engine Speed (RPM) DTC Set

FREEZE FRAME DATA • Captured when either pending or mature DTC is set & MIL is illuminated • Only 1 is stored – For the first DTC only • A misfire of fuel control DTC of a higher priority can overwrite a lower priority Freeze Frame • Only the Freeze Frame will be overwritten - not the DTC!!!

FREEZE FRAME DATA • Uses… – Diagnostics - to analyze the conditions the vehicle was being operated when the fault appeared – Repair Verification - Fuel System & Misfire MILs can only be turned off after 3 trips under similar conditions

FUEL TRIM • The ability of the computer to deviate from the look-up table • A low O 2 voltage/lean exhaust will result in the Fuel Trim adding fuel / + % #s • A high O 2 voltage/rich exhaust will result in the Fuel Trim subtracting fuel / - % #s

EVAP MONITOR • The object of this monitor is to verify canister is being purged and that the systems is not leaking fuel vapors into the atmosphere (0. 040 / 0. 020 size leak) • Pressure is done via a Differential Pressure Sensor measuring vacuum or pressure • Purge is done by measuring O 2 and/or Fuel Trim • 2 trip DTC/MIL

O 2 S MONITOR • Tests all Oxygen Sensors • O 2 Sensors must be calibrated – minimum voltage – maximum voltage • O 2 Sensors must react fast – activity – rate of change • 2 trip DTC/MIL

Oxygen Sensor • Location Designation – The lower the number, the closer the sensor to the front of the engine or front of the bank – Bank 1 is where cylinder #1 is – Bank 2 is the other bank – The highest number usually designates the post-O 2 S

COMPREHENSIVE COMPONENT MONITOR (CCM) • Continuous Monitor of emission control related items not specifically monitored by the task manager. • Constantly monitors for opens, shorts, and grounds, • Can monitor rationality if enable criteria is met • DTC’s can be 1 or 2 trip

Continuous & Non-Continuous Monitors • Continuous – Misfire – Fuel System – Comprehensive Component Monitor • Non-Continuous – Catalyst – EGR – EVAP – O 2 S Heater – Catalyst Heater – AIR

CATALYST MONITOR • Objective is to determine if catalytic converter is operative • Compares the frequency & amplitude of Pre & Post O 2 Ss (voltage level? ) • If Post O 2 S activity is similar to of Pre O 2 S – Cat must not be working – O 2 S might be bad – Conditions needed to operated cat might not be being created • Monitor is run once per trip and DTC is a 2 tripper

MISFIRE MONITOR • Objective is to detect misfires that could elevate emission by 50% and/or damage catalyst • Main misfire sensor is engine speed – CKP & CMP • 2 types of misfires – Catalyst damaging (severe) - flashing MIL – Misfire that will result in emissions rising 50% above FTP • Enable criteria includes - MAP, RPM, ECT, Start-to-run time, & VSS

DEFINITIONS • OBD II - Gov’t regulations that mandate faults that result in a 50% increase in emissions be identified, the operator warned, and diagnostics standardized. • Warm-Up Cycle - Start-to-run where ECT increases 40° F and the temperature rises above 160° F • Rationality - comparing sensor/actuator values against others to determine their calibration

GENERIC SCAN TOOLS (GST) • WILLs – – – Read PIDs Readiness Status DTC’s Freeze Frame Data Connect to any OBD II vehicle • WON’Ts – Be as fast as vehicle specific or Hybrid – Diagnose vehicle for you – Fix vehicle for you

TRIPS • Definition – A sequence of events and a set of conditions that must be met for a specific monitor to run • Uses – To test a system to verify a complaint or repair – To turn on or turn off MIL

OBD II DIAGNOSTICS • DTCs cannot be verified unless code enable criteria has been met • For OBD II to work correctly all OBD I systems have to be OK • No communication problems can sometimes be diagnosed at the DLC