530 likes | 541 Views
ECMs and Air Bag Modules:. By Patrick Riedlinger , P.E., ACTAR. Electronic Data Recorders. Data recorded in certain situations Collision Hard braking / “sudden stop” Diagnostic “snapshot” Data can be used to assist in collision reconstruction or mechanical failure analysis
E N D
ECMs and Air Bag Modules: By Patrick Riedlinger, P.E., ACTAR
Electronic Data Recorders • Data recorded in certain situations • Collision • Hard braking / “sudden stop” • Diagnostic “snapshot” • Data can be used to assist in collision reconstruction or mechanical failure analysis • Passenger vehicles – ACM and/or PCM • Commercial vehicles – electronic control module (ECM)
Passenger Vehicles • Bosch Crash Data Retrieval (CDR) system • Images crash data from air bag control module (ACM) and/or powertrain control module (PCM) • Download through vehicle’s electrical system • Electrical system mostly intact and need key • Some newer GM vehicles don’t require a key • Can do workaround for download w/o key
Passenger Vehicles • Download directly from module • In-vehicle: Electrical system damaged • Out of vehicle (“Benchtop” download): Vehicle damaged, or model not supported at time of investigation • Caveat: Can set trouble codes on Ford and Chrysler vehicles • http://www.boschdiagnostics.com/testequipment/cdr/Pages/CDRHome.aspx
Available Vehicles • 1994 – 2017 General Motors • 2001 – 2017 Ford, Lincoln & Mercury • Some 2005 – 2017 Chrysler, Dodge & Jeep • Some 2001 – 2017 Toyota, Lexus & Scion • 2012 - 2017 Fiat 500 • 2012 - 2017 Honda, Acura • 2011 – 2017 Volvo
Available Vehicles • 2012 -2017 Nissan and Infiniti • 2013 – 2017 BMW • 2013 – 2014 Rolls-Royce Ghost • 2013 - 2017 Kia & Hyundai (after 9/1/2013) (Not Bosch) • 2011 – 2017 Mazda • 2014-2017 Mercedes Benz (extra equipment needed) • 2014-2017 Mini
Available Vehicles • 2013 – 2014 Suzuki • 2005 – 2009 Saab 9-7X (Chevy Trailblazer) • 2009 – 2013 Volkswagen Routan (Chrysler) • 1998 – 2000 Isuzu Hombre (Chevy S10) • 2007 – 2010 Suzuki XL-7 (Chevy Equinox) • 2003 - 2008 Isuzu Ascender (Chevy Trailblazer)
Available Vehicles • 2005 – 2010 Mitsubishi Raider (Dodge Dakota) • 2008 – 2009 Sterling Bullet class 4/5 truck • Jaguar / Land Rover - send to manufacturer
Bosch CDR • Airbags need NOT deploy to have data • Deployment event • Collision severe enough to deploy airbags • Data “locked” and cannot be erased • Non-Deployment event • Collision severe enough to “alert” system but not severe enough to cause deployment • Data can be erased by ignition count or another Non-Deployment event
Bosch CDR • Type of impacts to record data • Frontal impact: all vehicles (some need air bag deployment) • Rear-end impact: some vehicles • Side impacts: some vehicles • Rollovers: some vehicles
Stored Data • What data is stored on your vehicle? • Dependent on the vehicle’s year, make and model. • Data may be identified by ignition cycles. • Data IS NOT date/time stamped • Some data can be overwritten
Potential Data Stored • SIR warning lamp status • Driver and passenger seat belt switch status • Ignition cycles at Event • Ignition cycles at investigation
Potential Data Stored • Time from algorithm enable to airbag or pretensioner deployment • Indicate which stage and when the deployment command was issued • Time from Non-Deployment to Deployment • Time between recorded events • Longitudinal and/or lateral speed change (Delta-V) vs. time
Potential Data Stored • Diagnostic codes active at event • Lateral and longitudinal acceleration • Air bag module configuration • What components are installed in subject vehicle • Parking brake switch ON/OFF status • ABS warning light ON/OFF status • Driver’s seat track position
Potential Data Stored • MIL (malfunction indicator light) ON/OFF status • Cruise Control ON/OFF status • Air bags deployed or not • Roll angle, lateral acceleration, longitudinal Delta-V, lateral Delta-V: depends on the type of event recorded
Potential Data Stored • Pre-Crash data (length of time recorded varies) • Vehicle speed • Measured at transmission, not ground • Engine speed • Throttle position • Accelerator pedal position
Potential Data Stored • Pre-Crash data continued • Brake switch circuit status • Not brake level, just “On” or “Off” • Steering wheel angle • Yaw angle/rate
EDR Laws • Federal: 49CFR563 • Applies to passenger vehicles manufactured after 9/1/2012 • Specifies what must be recorded IF any data is recorded
EDR Laws • Several states have laws governing EDR data • AR, CA, CO, CT, ME, NH, NY, NV, ND, OR, TX, VA & WA • Laws are different in each state • Some laws apply to vehicles manufactured after a certain date • State laws need to be followed for admissibility
Commercial Vehicles • Event data is stored in the Engine Control Module (ECM) and possibly other modules • Detroit Diesel, Mercedes, Caterpillar, Cummins, Mack and International • Volvo: Configuration data only • “Hard Stops” must be enabled • Mack modules must be sent to authorized company (2)
Commercial Vehicles • Electrical system needs to be somewhat operational and need the key • If truck significantly damaged or no key: • Connect directly to modules. • Remove module(s) and download on benchtop or in surrogate truck • Benchtop download may set diagnostic codes
Types of Data in an ECM • Fault Data • Assists in maintenance & diagnosis • May include “snapshot” of speed, RPM, etc. • Historical Data • Calibration Settings • Vehicle configuration • Important for validating reported speed
Types of Data in an ECM • Event Data • Typically, Quick Stop / Last Stop events • Easily overwritten • “Quick Stop” must be enabled
Relevant Configuration Data • Governor speed limit (fuel cutoff) • Soft speed limit (tattle-tale) • Top engine RPM • Hard brake threshold (0=no hard brake events) • Min/max cruise control set speed • Tire size (revolutions per mile) • Axle ratio
Historical / Trip Data • Trip start and end date • Trip distance • Odometer at download • Average and highest speed • Time and date of highest speed • Number of vehicle overspeeds • Date and time of diagnostic codes
Pertinent Event Data • Date and time of event • MUST reconcile ECM clock with “real time” • Sometimes must use engine hours (Cummins, Mack) • Odometer reading • Vehicle and engine speed • Cruise control (on/off) and set speed
Pertinent Event Data • Brake and clutch application • Percent throttle applied