Tuesday, September 25, 2018

Potentially deadly automotive software defects

Here's a list of potentially deadly automotive software defects, mostly from NHTSA Recall notices.

There is still a lot of resistance to the idea that car software can have fatal defects that result in deaths not due to driver error. In fact such defects do exist, and for many of them we've just gotten lucky that few or no people have died as a result. Recently we've been seeing more deadly software defects being reported. This posting is intended to give a taste of what's been going on in automotive software quality. This is a very partial list of bad software that was deployed on production vehicles in the US.

This list includes a variety of subsystems including unintended acceleration, steering failures, brake assist failures, headlights going out while driving, and quite a lot of air bag failures. There are software defects, configuration management errors, leaving the module in "factory mode" when shipped, and even EEPROM wearout. Overall this paints a picture of an industry that is shipping a lot of safety critical software defects.  In fairness, yes, these are all ones that are being fixed, and there are certainly other causes of fatal accidents. (Presumably there are others not yet being fixed, if for no other reason than that the cars are still new on the road. But at least some of these recalls sure look like mistakes that simply should not be happening in life critical software.)

The list is almost certainly much, much longer, and I simply ran out of time trying to go through the full NHTSA database.  And even that doesn't include everything that happens. The list is heavy in 2013-2015 mostly because that was the most convenient source material I found. There is no reason whatsoever to believe things have gotten dramatically better since then.

The purpose of this list is not to call out any particular company or software defect. Rather, the point is that safety critical software defects are both pervasive and persistent across the automotive industry.  Yes, we can have discussions about how many vehicles vs. how many defects. But it still does not instill confidence about life critical software in a self-certifying industry that in the US is not required to follow international software safety standards.
  • "Automatic braking systems in some Nissan Rogues are going rogue, safety group says" / Mar 2019
  • "Alfa Romeo recalling 60,000 vehicles to repair cruise management fault" / Mar 2019
  • "Ford recalls 1.5 million Ford Focus cars that could stall with fuel tank problem" / Oct 2018
  • "Toyota recalls trucks, SUVs and cars to fix air bag problem" / Oct 2018
    • "Toyota says the air bag control computer can erroneously detect a fault when the vehicles are started. With a fault, the air bags may not deploy in a crash. The company wouldn't say if the problem has caused any injuries."
    • https://www.abc57.com/news/toyota-recalls-trucks-suvs-and-cars-to-fix-air-bag-problem
  • "Toyota isssues second prius recall in a month on crash risk" / Oct 2018
  • "Safety systems may be disabled when in use" (Mitsubishi) / Sept. 2018
    • "Inappropriate" software in the hydraulic ECU causes the pump to generate electrical noise that resets the ECU. That reset can cause: automatic braking to be cancelled, wheels lock momentarily, stability control to be momentarily cancelled, release break of brake auto-hold is active.
    • NHTSA recall 18V-621
  • "GM recalls more than 1M pickups, SUVs for power steering problem" / Sept. 2018
    • 30 crashes; two injuries, no deaths attributed
    • Voltage drop and return causes momentary power steering failure; fixed via software update
    • https://www.freep.com/story/money/cars/general-motors/2018/09/13/gm-recall-pickups-suvs-power-steering/1287911002/
  • "Expert investigation says BMW software to blame" / Aug 2018
  • "Fiat Chrysler recalls 5.3 million vehicles for cruise control defect" / May 2018
  • Incorrect Speed Limitation Software (Mercedes-Benz) / 2018
    •  These vehicles may be equipped with the incorrect reverse speed limitation software. While in reverse, any abrupt changes in steering while exceeding 16 MPH may cause the vehicle to become unstable.
    • NHTSA recall 18V-457
  • Cruise control may not disengage (Mercedes-Benz) / 2017
    • ESP software malfunction may cause engine not to reduce power regardless of speed, driving situation, or brake application.
    • NHTSA recall 17V-713
  • "Fiat Chrysler recalls 1.25 million trucks over software error" / 2017
  • Unintended vehicle movement (Ford) / 2017
    • Quick movement of gear shift can cause up to 1 second selection of reverse gear when shifting into intended drive (forward) gear.
    • NHTSA recall 17V-669
  • Air bags may not deploy in a crash (Mitsubishi) / 2017
    • SRS ECU misinterprets vibrations, disabling air bags from deploying in a crash
    • NHTSA recall 17V-686
  • Unintended acceleration failsafes "missing" (Dodge) / 2016
  • Inadvertent Side Air Bag Deployment (Chrysler) / 2015
    • Unexpected side airbags may unexpectedly deploy due to incorrect software calibration; may result in crash or injury
    • NHTSA Recall 15V-460 and 15V-467
  • Radio Software Security Vulnerabilities (Chrysler) / 2015
    • Exploitation of the software vulnerability may result in unauthorized remote modification and control of certain vehicle systems, increasing the risk of a crash.
    • NHTSA Recall 15V-461, 15V-508
  • "Toyota recalls 625,000 hybrids: Software bug kills engines dead with thermal overload" / July 2015
    • Software settings for motor/generator ECU cause thermal damage, then propulsion shutdown
    • https://www.theregister.co.uk/2015/07/15/toyota_recalls_625000_hybrids_over_enginekilling_software_glitch/
    • Note previous recall 14V-053 for similar sounding problem
  • Tire pressure monitoring system message (Ferrari) / 2015
    • TPMS displays 50 mph speed limit warning instead of "do not proceed" warning due to software defect. Driving on punctured tire would cause loss of vehicle control and crash.
    • NHTSA Recall 15V-306
  • Airbag Incorrect Deployment Timing (BMW) / 2015
    • Driver front air bag timing incorrect / fails to meet FMVSS 208 due to programming error
    • NHTSA Recall 15V-148 
  • Passenger Air Bag may be disabled (Jaguar) / 2015
    • Light weight adult may be misclassified, disabling air bag
    • NHTSA Recall 15V-093
  • Unintended side air bag deployment (Chrysler) / 2015
    • Unintended side curtain and seat air bag deployment during operation / software reflash
    • NHTSA Recall 15V-041
  • Brake controller might not activate trailer brakes (Ford) / 2015
    • Trailer brakes not activated when towing, lengthening stopping distance, increasing risk of crash. Fixed via powertrain control module reflash.
    • NHTSA Recall 15V-710
  • On but unattended vehicle may cause CO poisoning (GM) / 2015
    • Vehicle may turn on gasoline engine to recharge hybrid battery, causing carbon monoxide poisoning (e.g., if car is in garage)
    • NHTSA Recall 15V-145
  • Incorrect electric power steering software setting (Jaguar) / 2015
    • Power steering set in factory operating mode. Vehicle can experience additional steering inputs from EPS causing driver to lose ability to control the vehicle.
    • NHTSA Recall 15V-569
  • Air bag may not detect passenger in seat (Nissan) / 2015
    • Configuration management error: incorrect occupant classification software version installed, resulting in no air bag deployment
    • NHTSA Recall 15V-681
  • "Honda admits software problem, recalls 175,000 hybrids" / July 2014
  • Transmission calibration error (Ford) / 2014
    • Due to software calibration error vehicle may be in and display "drive" but engage "reverse" for 1.5 seconds.
    • NHTSA Recall 14V-204
  • Headlights may unintentionally turn off (Motor Coach Industries) / 2014
    • A mux controller may unintentionally turn off headlights while vehicle is in gear
    • NHTSA Recall 14V-370
  • Brake vacuum pump may stop functioning (Mitsubishi) / 2014
    • Software defect causes false detection of stuck relay, disabling brake power assist
    • NHTSA Recall 14V-522
  • Loss of brake vacuum assist (GM) / 2014
    • Loss of power brake assist; fixed with software reflash
    • NHTSA Recall 14V-247
  • Reprogram sensing and diagnostics module (GM) / 2014
    • Module left in "manufacturing mode" when shipped, disabling airbags
    • NHTSA Recall 14V-247
  • Passenger airbag may be disabled (Jaguar) / 2014
    • EEPROM wearout (which is due to a software defect) causes airbag to be partially or totally disabled
    • NHTSA Recall 14V-395
  • Hybrid transmission software (Champion Bus) / 2014
    • Software may improperly raise vehicle's engine speed during downshifts without the driver's input. The increase in speed may result in unintended acceleration.
    • NHTSA Recall 14V-303  (See also 14V-043; 14V-043 Navistar; 14V-026 Kenworth)
  • Cruise control unintended continued acceleration (Chrysler) / 2014
    • Unintended continued acceleration after releasing accelerator due to adaptive cruise control software; may increase risk of crash
    • NHTSA Recall 14V-293
  • Side-curtain rollover airbag deployment delay (Ford) / 2014
    • Errors in the programming software which may result in delayed deployment of side-curtain rollover airbag
    • NHTSA Recall 14V-237
  • Improper seat belt restraint software (Toyota) / 2014
    • Improper software can use insufficient force in crash (e.g., 110 pound passenger force for larger passenter)
    • NHTSA Recall 14V-272
  • Air bag may not detect passenger in seat (Nissan) / 2014
    • Software may incorrectly classify passenger seat as empty; airbag will not deploy
    • NHTSA Recall 14V-138
  • Vehicle may gradually accelerate unexpectedly (Nissan) / 2014
    • If lost signal from throttle position sensor is regained (intermittent fault) fail-safe mode is deactiveted, opening throttle resulting in "gradual" acceleration due to software error.
    • NHTSA Recall 14V-583
  • Inadvertent Air Bag deployment (Ram) / 2014
    • Side air bags deploy when hitting potholes; fixed via software update
    • NHTSA Recall 14V-528
  • Side airbags may deploy on the incorrect side (Chrysler) / 2013
    • Airbag on the wrong side of the vehicle could deploy, leaving occupants with no airbag protection at point of impact due to a software defect
    • NHTSA Recall 13V-283
  • Delayed deployment or non-deployment of airbags (Chrysler/Jeep) / 2013
    • Airbag deployment delayed or no airbag deployment in rollover due to software defect
    • NHTSA Recall 13V-233
  • Airbag deployment software (Chrysler) / 2013
    • Incorrect software installed; air bags may not deploy or might deploy improperly
    • NHTSA Recall 13V-291
  • Improper occupant classification / 2012
    • Incorrect software installed that misclassifies passengers; airbag might not deploy when it should, deploys incorrectly, or deploys when it should not
    • NHTSA Recall 12V-198
  • Occupant classification system (Hyundai) / 2012
    • Software might miss small stature adults and not deploy airbag.
    • NHTSA Recall 12V-354 
  • Cruise Control System/Brake Switch Failure (Mercedes-Benz) / 2011
    • Brake pedal may not automatically disengage cruise control as expected. (Other methods still work.)  If driver pumps brakes it will take unusually high force to stop vehicle.
    • NHTSA Recall 11V-208
  • Engine stall prevention assist software (Honda) / 2011
    • Unexpected vehicle movement from ECU software providing hybrid electric power and unexpectedly moving vehicle in reverse direction if the engine stalls.
    • NHTSA Recall 11V-458
  • Loss of steering power assist (Toyota) / 2010
  • "Toyota: software to blame for Prius brake problems" / 2010
  • ABS ECU Programming (Toyota) / 2010
    • Inconsistent brake feel; increased stopping distances for a given pedal force due to ABS programming, raising the possibility of a crash.
    • NHTSA Recall 10V-039
  • Restraint control module (Land Rover) / 2009
    • Passenger airbag disabled as a result of temporary loss of CAN network messages and a software defect
    • NHTSA Recall 09V-467
  • Double Clutch Gearbox (BMW) / 2008
    • Engine stall increasing risk of a crash due to software multistage downshift defect
    • NHTSA Recall 08V-595
  • Passenger sensing system (GM) / 2008
    • Software condition within passenger sensing system may disable passenger air bag (or enable when it should be disabled).
    • NHTSA Recall 08V-582
  • Passenger air bag fail to deploy (Nissan) / 2008
    • Passenger air bag might not deploy due to low battery voltage combined with software defect
    • NHTSA Recall 08V-066
  • Engine Control Module Software Update (VW) / 2008
    • Software defect can cause unexpected engine surge that can "result in a crash without warning."
    • NHTSA Recall 08V-235
  • SRS Electronic control unit software (Maserati) / 2007
    • Passenger air bag might not deploy if car battery is not fully charged due to software defect
    • NHTSA Recall 07V-550
  • SRS control unit software (Volvo) / 2007
    • Two software errors result in late deployment of side airbags
    • NHTSA Recall 07V-500
  • Passenger side airbag does not deploy (Volkswagen) / 2006
    • A weak battery could cause air bag control unit to deactivate due to a software defect; airbag will not deploy in a crash
    • NHTSA Recall 06V-454
  • Electronic Throttle Control (GM) / 2006
    • ETC torque monitoring failsafe disabled, permitting throttle opening greater than commanded (i.e., UA) due to a software defect
    • NHTSA Recall 06V-007
  • Powertrain control module (DaimlerChrysler) / 2006
    • Software can cause momentary lock up of drive wheels at speeds over 40 mph if operator shifts from drive to neutral and back.
    • NHTSA Recall 06V-341
  • BMW/Driver's seat occupant detection system / 2004
    • Software can't reliably determine if driver seat is occupied; airbag may not deploy.
    • NHTSA Recall 04V-379
  • Jaguar/Forward drive gear / 2004
    • Selecting forward drive gear could select reverse while in forward motion, without indication. (Apparent limp home mode logic defect.)
    • NHTSA Recall 04-024
  • BMW/ENgine Idle Speed/DME Idle Control / 2003
    • Increase of idle speed up to 1,300 RPM. If a gear is selected, the driver may feel as if the vehicle is being pushed.
    • NHTSA Recall 03V124
  • KIA/ABS Electronic Control Module / 2003
    • A programming error in ABS cases reduced braking force at speeds below 25 mph, extending stopping distances
    • NHTSA Recall 03V-158
  • "GM Admits Brake Flaws After Inquiry" / July 1999
  • Chrysler/Interior systems: air bag / 1996
    • Air bag software error which can delay air bag deployment
    • NHTSA Recall 96V-060

Noteworthy: These are software-related problems with cars that are worth knowing about, but less black and white because, for example, there has been no general recall issued.
  • To access NHTSA recalls you need to visit https://www.nhtsa.gov/recalls then select Vehicle then select "search by NHTSA ID" which can take a few mouse clicks to find on the indicated NHTSA web site.  (It might be the interface has changed since I posted this; you might need to poke around to find the lookup function.)
  • This is a work in progress and a VERY incomplete list.  I thought this would be a one-day exercise, but, well, no. If you know of something really important I've missed, please let me know!  More importantly, if you know of someone who is interested in maintaining a list like this, especially as a more rigorous academic study, I'd be happy to collaborate.  I simply don't have the time to keep up with this.
  • Reasonable people can perhaps disagree about the inclusion or exclusion of some items. But the point is really more about the volume rather than any individual item. By definition each recall is a defect that should not have been shipped, because it resulted in a recall.  I've paraphrased the recall reports. If you want to know more be sure to look at the supporting documents on the NHTSA web site, which often have more details than the summaries.
  • To be "deadly" these defects have to be software faults that either have caused, could reasonably cause, or should have reasonably prevented significant injury or death. (This includes defects in failsafes, for example) A partial list includes: un-commanded acceleration (UA), stalling at speed (dangerous when merging onto a highway), failure to deactivate cruise control, extended braking distances, airbag disablement, and incorrect airbag deployment.  What happens in practice depends upon the circumstances.
  • This should not be construed to be an expert opinion of root cause of any particular mishap. I am summarizing publicly available information and have not independently verified the technical facts in each case. Those public sources might be incorrect, or I might not have fully understood the implications of the statements in those sources. Again, this is more about the overall trend and not any particular incident report.
  • There are plenty of commenters who say things for unintended acceleration like "just apply the brakes, because brakes always overcome the engine." First, this is simply not true in many situations due to loss of vacuum assist, drivers with weak leg strength etc. A single point fault or sufficiently likely multi-point fault should not be trying to kill the occupants in the first place, so it's still a defect.
  • The air bag software problems were found in: https://www.autosafety.org/staging/wp-content/uploads/import/Historical%20Airbag%20Recalls_1.pdf  I independently verified them on the NHTSA database.
  • I independently verified on the NHTSA database some drivetrain recalls found here: https://www.autosafety.org/sites/default/files/imce_staff_uploads/Exemplary%20Vehicle%20Software%20Recalls.pdf
    and here: https://www.autosafety.org/wp-content/uploads/2016/04/2014-15-Software-Recalls.pdf
  • If you want to go exploring, you can download a copy of the raw database here that I used for some of the other defects: https://www-odi.nhtsa.dot.gov/downloads/


  1. We wrote a survey paper a couple years ago on such issues (to early 2015 data), & also looked at other regulatory bodies (Transport Canada, RAPEX), which you might find interesting: Survey of Electrical & Electronic (E/E) Notifications for Motor Vehicles: https://www-esv.nhtsa.dot.gov/Proceedings/24/files/24ESV-000063.PDF

  2. Thanks for a great article Phil! If you don't mind I'll share this article in my robotics newsletter (https://weeklyrobotics.com/), I believe lots of those lessons could be useful for anyone working on any kind of robotics system.

    1. Yes, it is fine to share it with attribution.
      -- Phil


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