Text of OBD II UPDATE TRAINING COURSE. OBD II Module Outline OBD II Foundation OBD II History OBD II...
OBD II UPDATE TRAINING COURSE
OBD II Module Outline OBD II Foundation OBD II History OBD II Terminology OBD I vs OBD II 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 Didnt always illuminate when a problem was detected! WAS INCONSISTENT!!!
Serial Data Live Computer Data Supplied by the vehicles computer Read via a Scan Tool Interpreted Data GM, Chrysler, then Ford Now mandated by OBD II
Diagnosing Todays Vehicles Technician must have a strong foundation in system operation & theory!!! Technician must have ability to fully utilize todays 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 O2S 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 vehicles emission control system / strategy Diagnostics & Functions must be standardized
OBD II Requirements PCM must store DTCs for detected faults DTCs 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 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 J2012
DTC Numbering 1st Digit Alpha Character P - Powertrain C - Chassis B - Body U - Uart / multiplexing / networking
DTC Numbering 2nd Digit or thousandth position Either 1 or 0 0 Codes are SAE / OBD II Controlled 1 Codes are Manufacturer Specific
DTC Numbering 3rd 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 3rd Digit or hundredth position System Fault 500 - Vehicle Speed and/or Idle Control 600 - Computer Output Circuits 700 - Transmission 800 - Transmission
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 P0134 - HO2S - 11 Remains At Center (B1 S1) 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 HO2S-11 signal was 0.5v (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
When 1st trip fails Code is pending or maturing Freeze Frame data is captured, but not displayed MIL is off TWO/THREE TRIP DTCs
If & When 2nd 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 TWO/THREE TRIP DTCs