Sudden acceleration: is it for real? - Weekend

Sudden acceleration: is it for real?

Jerome NeriAtty. Jerome G. Neri
The Scrutineer

IN THE past, month I have seen three pictures on social media of crashed Mitsubishi Montero Sport SUVs. In all these photos, the poster blamed the SUV, claiming that it has a sudden acceleration issue. There was one particular Montero that crashed into a car in the rear and then crashed to a building in the front, with the poster claiming that when he engaged reverse, the car suddenly accelerated and he hit a car behind hard, so he put it into drive, then the car accelerated to the building. It seemed that the engine was on full power that no matter how hard he stepped on the brakes, the Montero kept moving forward.

This sudden acceleration issue of the Montero Sport has been going around since 2010, so that in 2011 Mitsubishi Motors Philippines issued a press statement that they have conducted thorough tests on all the electrical systems of the Montero Sport and have found no problems with it.

CLOSURE NEEDED. What’s the best way to resolve once and for all the “sudden acceleration” allegations made by some Mitsubishi Montero Sport unit owners in the Philippines since 2010? (AP FOTO)
CLOSURE NEEDED. What’s the best way to resolve once and for all the “sudden acceleration” allegations made by some Mitsubishi Montero Sport unit owners in the Philippines since 2010? (AP FOTO)

Mitsubishi further explained that the probable cause of this issue is that the driver must have stepped on the wrong pedal — instead of hitting the brakes, the driver stepped on the accelerator thereby causing an accident.

What bothers me is the sheer number of claims from Montero Sport owners claiming that they crashed due to this sudden acceleration problem. But as a lawyer, I know too well that the huge number of complainants is not evidence enough to conclude that there really is a defect with the Mitsubishi Montero Sport. Likewise, determining whether or not there is some electrical gremlin within the Mitsubishi Montero Sport that can cause this sudden acceleration would be extremely difficult.

I’ve spoken to colleagues in the motoring media and fellow tuners and car technicians regarding this problem and opinions are well divided. There are those who think that the problem does not exist and it is owners/drivers who made a mistake and are trying to escape liability. The others think that Mitsubishi Motors has not done enough to assure the motoring public that this problem does not exist. No one can conclusively say that the problem exists.

On the technical side, modern cars such as the Mitsubishi Montero Sport do not have accelerator cables anymore. Throttles nowadays are drive-by-wire, meaning they are electronically controlled. The accelerator pedal in a modern car is a foot position sensor. It senses how much it is depressed and this signal will be sent to the engine control unit (ECU), which will then send an output signal to the engine and tell it how much power to give.

The foot position sensor is a 0-5 volt sensor. It works like a potentiometer: there is a 5-volt reference input voltage to the pedal, while the output voltage, which goes to the ECU, is between 0-5, depending on how much the accelerator is pressed.

For sudden acceleration to happen, the foot position sensor must give out a voltage signal to the ECU telling the ECU that the accelerator pedal has been pressed even if it has not been pressed. This can happen with a defective foot position sensor, but when there is such a defect, it should not just be a one-shot or one-time deal — the defect should keep on manifesting itself.

Another scenario would be that there is stray electricity that goes to the signal wire of the foot position sensor, thereby telling the ECU that the accelerator was pressed. Electrical gremlins like these should be able to manifest more than once.

I have not seen a sudden acceleration post of the same Montero Sport more than once. Moreover, ECUs have a failsafe system to prevent things like this from happening. In fact, I have experienced an electronic throttle failure with another car brand. What happened was the check engine light lit up and the engine stayed at idle no matter how I pressed on the accelerator pedal. After scanning for the problem with an OBDII engine scanner, the error recorded was “Electronic Throttle System Malfunction.”

The failsafe kicked in and had to have the car towed to the shop. All modern cars have failsafe features programmed in their ECUs.

With the numerous claims of sudden unintended acceleration of the Mitsubishi Montero Sport, there are not many cases filed against Mitsubishi Motors Philippines. I know of three and one has already been dismissed. The fact that there are not even 10 percent of those who claim to have been victims of the sudden unintended acceleration has filed a case does not mean that those alleged victims are making false claims. It is just it is a very difficult claim to prove in a court of law, as it would mean that the claimant would need a battery of electrical engineers and software engineers to look for and show the defect. This will cost a whole lot of money.

If there really is a defect with the Montero Sport, there should also have been similar reports from other countries, something that I have not heard of. I did some searching for this problem over the Internet and all the complaints I see are from the Philippines.

Mitsubishi Motors did what it is supposed to do: they conducted an internal investigation and had all the systems of the Mitsubishi Montero Sport checked by engineers in their mother company in Japan. The problem is such a self serving-investigation will never be enough to give the consuming public full confidence on the Mitsubishi Montero Sport.

The appropriate thing to do here is for government to step in and do an investigation on the matter. With the sheer number of complaints and for public safety, the Department of Transportation and Communication should be duty bound to put this matter to rest.

10 thoughts on “Sudden acceleration: is it for real?

  • November 14, 2015 at 1:29 am

    Nov 10,2015 @9 am, from parking when shifted to drive, without stepping the accelerator yet, my MONTERO ran so fast ( leaving skidmark) hitting a tricycle then two motor bikes that was dragged under,it continued accelerating and no matter how I step on the brake didn’t work then it turned turtle, when we crawled out I noticed that the engine continue running wild til it emits huge black smoke. I assume that when we turned turtle, the speed was approx 100kph and the distance from where I parked is 60 meters so therefore in a distance of 60 meters it gained speed of @100kph. That is unusual, hard to attain even intentionally for a matic, this happened in the vicinity of public market of sta maria bulacan, a crowded place

  • November 21, 2015 at 2:41 am

    It may not be entirely a Montero issue because other brands have experienced the same. Montero may have been on the forefront because so many people are using them now-a-days.

    Whether it is the fault of the driver or some sensor issues with the car, Mitsubishi really has to exert all efforts to see what is going on. Otherwise, they may lose a substantial market on this make.

    What I want to know are: Can the driver shift to neutral during this alleged episode? Is it possible to switch off the engine jeopardizing the braking pressure (as a result)? Mitsubishi speak up and do something to appease your customers. Make it immediate on what to do in case of this unintended acceleration? You said the drivers may have stepped on the gas pedal instead? How sure are your?

  • November 21, 2015 at 7:36 pm

    I entirely agree with Atty. Neri’s proposition for the DOTC to step in and do a separate investigation on this matter. An internal investigation by the Mitsubishi engineers is not credible enough as they can cover up any malfunctions there may be for the sake of their own company. They realize how much it will cost them if they make a false move of admitting that there is a jinx on their own vehicle, so this investigation (Mitsubishi’s) will be deemed useless.

    I do not own a Mitsubishi Montero Sport but I was planning to purchase one in place of my good Mitsubishi Adventure reason why I am trying to find any pros and cons prior to acquiring one then I found this. In due course, if I do not see any related matters or any development regarding this hiccup, I may have to think twice in buying this unit considering a different brand of SUV.

  • November 23, 2015 at 12:03 am

    Just like to know if all these accidents happened in GLS V Montero which has a turbo that could probably trap the air and cause this Sudden Unintended Accelerations. Were there any modifications done like EGR Blanking? if none, did it happen among none EGR BLANKED cars only? Does our weather condition here in the Philippines have an effect on Mitsubishi Transmission? If MMC wouldn’t give us an investigation I think we should do our investigation here by doing SURVEY QUESTIONNAIRES among those who experienced it and those who have not. I’m no expert on this but it would be a good start if somebody who has a background on engine and stuff to start making survey questionnaires.Thank you

  • December 1, 2015 at 4:50 am

    Sa experience ko ay maraming nga pong depekto ang Mitsubishi monterosport una po ay nakakaadik po yung amoy na nakakaadik po makipagtalik sa babae.Pangalawa ay nababasag mag isa ang side mirror at may suggestion po ako…Bigyan niyo po ang lahat ng may Monterosport ng 2 miliion pesos each..Ako po si Joel Bagang na nagsasabi wag po monterosport FJ Cruiser nalang..

  • December 1, 2015 at 4:53 am

    Marami na po akong na experience sa Monterosport una ang landi ng monterosport kailangan niyo pong tanggalin ang pagkalandi ng unit ninyo.
    At huli kailangan niyo pon gbigyan ng 2.5 million pesos ang lahat ng may monterosport eto po si Joel Bagang

  • December 1, 2015 at 6:48 pm


    Thank you for your interesting coverage of this “unintended acceleration” issue; we actually had been looking at a Montero purchase til we came across some of these crash histories.

    As you stated, very difficult to prove an issue that seems to occur “only once” and is never reproducible in a lab environment.

    I am reminded of some of the coverage of the Toyota Camry “sudden acceleration” issues of a few years back here in the USA. I saw at least one TV special where a researcher was able to “induce” a fit of sudden acceleration in the Camry by modifying the throttle circuit “just a tad” (adding a small resistance or something); their test Camry took off like someone lit its trunk on fire…

    But Toyota said, “that’s cheating”, that could never occur in real life, said they were trying to defraud the company.

    Well, maybe they were and maybe they weren’t — but what they “had” discovered was a “vulnerability”, i.e. a little bit of resistance decrease in the wrong circuit, and the car would go crazy.

    Having been involved in electronics for many years, I’ve seen the hazards of what they call a “condensing atmosphere”, where the air is perhaps just at or above the dewpoint where moisture in the air can condense out on surfaces. If this happens to be inside an electronic circuit then all sorts of “gremlins” can occur (in radios, TVs, presumably even in car electronics).

    Unless the CPU or control box is hermetically sealed (and also the sensors such as the throttle sensor), they “must” be prone to resistance changes in the circuit caused by moisture.

    It occurred to me that since the Philippines often has very high humidity in the atmosphere, then “if” there’s a vulnerability in the control system there is where you would most likely encounter it.

    A suitable test regimen might involve placing the vehicle in a controlled “damp” condensing environment, “then” see if the gremlin can be induced. (needless to say, don’t get anywhere near the vehicle while testing it…)

    If it can, then you’ve got a weather sealing issue, they need to improve the design of their sensors — or perhaps owners over-enthusiastically washed the vehicle before the accident occurred, etc. (you know computer and running problems can often be caused by someone trying to spray-wash an engine compartment)

    (I’ve seen transmission sensors fail, where they’re mounted underneath the vehicle and if the seal goes bad, road moisture can leak in and cause all sorts of weird shifting and other symptoms)

    After the Camry exposure, I’m surprised Toyota didn’t go back and try some experiments on their own — but seems nowadays all the mfg. will do is stonewall any possibility that they didn’t cover all the possible scenarios…

    Just some “amateur” thoughts for you to toss around —

  • December 2, 2015 at 4:27 am

    nakakabahala lang po na may nakaka adik na amoy na parang gusto mong kumantot refund ng 2m or fj cruiser nlng po…….

  • December 3, 2015 at 12:05 pm

    In other words, as a lawyer, you have no idea what tests, what type of tests, or what analysis Mitsubishi has done. Further, if this has only occurred in the Philippines (a BIG IF), that should aid MM PHILIPPINES in using their databases to verify that “fact”, THEN CONDUCT APPROPRIATE TESTS.

    As an automotive engineer, versed in statistical techniques, I would question whether a DOE with FULL FACTORIALS was conducted, and at what confidence interval? Further this situation lends to other statistical reviews. A thorough review of the design DFMEA would be helpful to start a proper investigation. I will not bother you with the notion that you could not possibly see the control plans for the sensor features production facilities. In a long career of supplying electronic and other components to auto manufacturers, I find your conclusions at best misleading. People will die or get seriously hurt following your advice.

    By the way, what is it you would want the govt to do? Any good consulting team, at the request of a good lawyer, can petition MM Philippines for the necessary data. If MMP refuses, then maybe the govt should be called in. In fact a good lawyer can use the judicial system to pursue these basic things.


    1. You have no basis for stating Mitsubishi has done all they should do.
    2. Further you are impugning the integrity of those who did report, thereby scaring away others who may have experienced the problem, but perhaps not as severely.
    3. I question your impartiality. It is blatantly foolish to suggest that the extreme acceleration reaction of the vehicle due to a potentially faulty foot sensor (if one is to take your word for this being the root cause, absent any real analysis) should not happen only once suggests you have been tracking each claimant over a period of time, and have seen not even a small symptom of the claim of unintended acceleration. Have you done this?

    You actually suggested that one driver may have improperly pressed the gas pedal on two occasions repeatedly. As absurd as that sounds electromagnetic devices can react to electromagnetic impulses from other signal delivery systems that happen to be engaged at the same time, in the same location, which I’m sure would suggest a re-design to prevent unwarranted electrical interference.

    All stated, such a review of MMPs surety programs regarding this matter should not be expensive a all. what might incurr expense is the degree to which a verification examination is executed. the document review is relatively inexpensive, and does not require a single software engineer, though one may be useful.

  • December 27, 2015 at 11:23 am

    A friend of mine owns a 2010 M-Sport V version. The accelerator pedal failed and the throttle was program via the ECU with a limited go home speed of 30kph no matter how fully depressed the accelerator pedal. This function varies because another golfmate’s Montero with similar complaint can only idle and not enough RPM to move the vehicle.

    My wife owns a 2011 with a 16K in the odometer. It visited Diamond 4 times for routine maintenance. No manifestation of SUA.


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