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OBD II UPDATE TRAINING COURSE

OBD II UPDATE TRAINING COURSE. 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. OBD II Module Outline. SESSION 1 OBD I FOUNDATION.

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OBD II UPDATE TRAINING COURSE

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  1. OBD II UPDATE TRAINING COURSE

  2. 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 OBD II Module Outline

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

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

  5. 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

  6. 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!!!

  7. 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

  8. 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

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

  10. OBD II Update Training Course Session II OBD II Foundation

  11. Session 1The 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

  12. 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!

  13. 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?)

  14. 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

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

  16. 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

  17. 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

  18. 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)

  19. 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

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

  21. 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

  22. 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!

  23. 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!!!

  24. 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

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

  26. 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

  27. 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!!!

  28. 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

  29. 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

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

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

  32. 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

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

  34. DTC Numbering • 4th & 5th Digits - tens & ones • Designate Specific Fault • Example • P0301 = Engine Cylinder # 1 Misfire Detected

  35. Diagnostic Trouble CodesOBD 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

  36. Diagnostic Trouble CodesOBD 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

  37. Diagnostic Trouble CodesOBD 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

  38. 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

  39. 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)

  40. 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.

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

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

  43. 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

  44. PENDING DTCs • If 2nd 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

  45. 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 Off One “bad trip” N/A Set N/A Set, but not displayed MIL Strategies & DTCsFirst Trip Failure

  46. MIL Strategy Exercise

  47. 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 & DTCs2nd Consecutive Trip Failure

  48. 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 Off Reset to zero N/A Set or cleared One “good trip” Displayed or not MIL Strategies & DTCs2nd Consecutive Trip Pass

  49. 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 & DTCsFault Repaired / DTC Not Cleared

  50. 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

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