Is it wrong to use an OBD device when inspecting used cars?

victorwilson on 08/06/2014 - 16:08
Last edited 08/06/2014 - 21:18

Hi all,

I am looking to buy a used car in the near future from a private seller (from Carsales). I want to make sure there are absolutely no problems with the car I wish to buy, and to avoid buying a car that would cost more than its value to fix.

Would it be unethical or rude to use an OBD2 diagnostic device (like this one) and an app such as Torque to check for any defects or problems in the car when I visit the seller to inspect the vehicle, assuming I ask permission beforehand?

Also, is there anything else that I should do to check if a used car isn't a lemon?

Automotive

Comments

  • tonyjzx on 08/06/2014 - 16:15
    +19

    ask first, if they say no, dont

    yes, you're gold

    your money, if you feel uncomfortable, walk

    if i was selling my car, i wouldnt mind a rude bastard buying it, their money is still good i'm told

  • DrStinge on 08/06/2014 - 16:42
    +2

    Another option is hiring a mobile mechanic to get an inspection; usually around $150.. not the cheapest option but I've done this in the past and have avoided a few lemons.

    • OzBLover on 10/06/2014 - 17:44

      That is damn cheap, I paid over $300 for the same service

      Are you in Vic btw?

      • DrStinge on 10/06/2014 - 18:31
        +1

        Currently yes, but this was when I was in QLD, have to shop around :)

  • p1 ama on 08/06/2014 - 18:16
    +1

    Would it be unethical or rude to use an OBD2 diagnostic device (like this one) and an app such as Torque to check for any defects or problems in the car when I visit the seller to inspect the vehicle?

    Nope, why would it be?

    As the buyer of a car, they should be providing you with all the information you want. If they don't want you to, then they have something to hide, so move along.

    If I was selling my car, I would be more than happy for you to use any device to check, as long as you don't damage my car of course :P

  • StewBalls on 08/06/2014 - 19:23
    +29

    Just for another perspective, as a seller, I wouldn't let you plug an unknown device into my expensive car computer.

    If you want diagnostic data you can have it done by a qualified mechanic by all means, but are you going to pay for auto electrical repairs if some cheap, crappy $5 device causes a fault in the system.

    Just something to bear in mind…

    • victorwilson on 08/06/2014 - 20:49
      +1

      Yeah, this is what I was worried the seller might think. I guess it won't hurt to ask?

      As a buyer, we should have a right to know what we're buying, but I definitely wouldn't want to be forced to buy a car which I damaged with a dodgy OBD device.

      I'm definitely no expert on cars; would there be any chance that a dodgy OBD device could irreversibly damage a car?

      • jace88 on 11/06/2014 - 07:26
        +1

        Nope but it might scare the seller into thinking you damaged the car if something went wrong later on.

        Agreed with first suggestion of asking first and seeing if they were comfortable. That being said, I think if you don't really know what you're doing or how to read the OBD codes, maybe just get a proper mechanic to do the checks.

  • blitz on 08/06/2014 - 19:53
    +4

    If I was selling a car and you showed up with such a device (I have two myself), I'd probably say no, or mount some way to even the transaction. See, if you test it and find no problem, well that's great for me too and I should be able to charge a higher price for the car. Likewise, I can also assert to other buyers that the OBD has revealed no errors, so it makes my car stronger in the market. All of this must be worth something to you, so I'd likely not budge on the asking price.

    Now let's say you test it, and find a problem (as would be the case with many cars, possibly even on spurious or negligible grounds). Now my car must be worth less on the market. Discovering that (and saving you the possibility of buying a lemon) must still be worth something to you, but I'd be out of pocket.

    As a seller I might consider running the OBD myself beforehand and supplying the readout with the car, but if you showed up with an OBD device and didn't look especially serious about purchasing I'd probably say 'no thanks'.

    • victorwilson on 08/06/2014 - 21:02
      +1

      Hmm true, that is a good point. If I were a seller and had no idea what an OBD was (probably the case with many ordinary sellers on Carsales), I would probably not trust the buyer.

    • NoApostrophePlurals on 09/06/2014 - 22:19
      +3

      Just because someone wants some peace of mind by using an OBD device, you shouldn't be seeking to "mount some way to even the transaction".

      It also doesn't make your car stronger on the market. This assessment only confirms what you are advertising. Your car is not the only faultless one on the market. Another seller who will allow an OBD diagnosis AND is willing to budge on the asking price would hold a stronger position than you, if you think your allowance of someone using such a device has some kind of magical intrinsic value.

      Whatever happened to goodwill and positive thinking?

        • sillyguy on 10/06/2014 - 13:19
          +8

          Wow, can I have your contact details so that I'll never buy anything from you.

        • blitz on 10/06/2014 - 16:50

          Why?

        • thejew on 10/06/2014 - 19:35
          +3

          LOL!

        • blitz on 10/06/2014 - 20:22
          +3

          Wow I really went off there, huh!

        • chukkii on 11/06/2014 - 09:31
          +3

          Well so you're saying that because the car your is fault free - as per your advertisement - I should have to pay more money when I confirm that?

          Say it wasn't an OBD device I used and I instead took it to a mechanic who confirmed the car is indeed faultless, should I also have to pay more?

          Would I have to pay more if I take it for a test drive and found it to be a smooth ride?

          Let me explain why your train of thought is so confusing. Let's say I buy a 2nd hand laptop that the seller claims is: "lightning fast, powerful and without any faults". I then ask to run diagnostics on the laptop which you then reply: "Sure, but if you run diagnostics and find that the laptop works as described, you will have to pay me more money"

          Your argument makes it sound like you're selling an unscratched ticket

        • whiznet on 12/06/2014 - 01:14

          blitz, you sound like you belong in a whirlpool forum.

  • ncmx5 on 08/06/2014 - 20:03
    +1

    good idea. never thought about doing this.

  • ferguscan on 08/06/2014 - 20:26
    +17

    Need consent before you insert anything into the seller's loved one.

    • victorwilson on 08/06/2014 - 21:03
      +1

      Yep, of course. Would be disastrous if the OBD damaged the car without the seller knowing exactly what I had done to it.

    • victorwilson on 09/06/2014 - 21:00
      +6

      I only just got the joke. Wow I'm slow.

      • DrStinge on 09/06/2014 - 21:15
        +3

        Better late than never ;)

        • NoApostrophePlurals on 13/06/2014 - 22:38

          not if you pull out. You'd wanna pull out earlier than later. Could end up being very time consuming. For both people involved. Pull out of the sale, that is.

  • Cheeper on 08/06/2014 - 22:40
    +2

    If you are asking this question ………
    "Also, is there anything else that I should do to check if a used car isn't a lemon?"
    ……….. then you should pay for the vehicle to be professionally inspected.

    It is the best assurance you can get to prevent buying a lemon. If you want to save the money then take the risk and wear the pain.

    An OBD will not detect every problem and a person half skilled in motor mechanics would find a lot more.

  • srhardy on 09/06/2014 - 08:14

    most RTA services do a presale inspection thats very compressive and if it turns up anything can be used to neg a better deal or you just walk and its a worthy outlay on anything over $5k IMO

    i know ozb like a deal and YES doing your own or taking a mechanic/mate can help and using something like the OBD can only help but lots more info than that needs to be taken into consideration IMO

    Ive learnt never to skimp on safety when it comes to things my immediate future hangs by! Whats your LIFE worth? Its ONLY a good deal if your alive to enjoy it and OZB is full of horror car scams stories and troubles; lives too short, who needs it!??!

  • thereyougo on 09/06/2014 - 08:23
    +1

    If I were the seller, I would clear any fault codes prior to selling then welcome any testing. An OBD isn't it going kill the computer it's when someone who doesn't know what they're doing by changing parameters causes damage.

  • Peck on 09/06/2014 - 09:18
    +1

    It is time for sellers of cars over a certain price to provide an inspection report from a professional body, rather than EACH buyer needing to pay for their own individual inspection. Sellers of houses should also have to do the same. It is time to throw out the 'buyer beware' mantra, and put more liablity onto sellers.

  • tanksinatra on 09/06/2014 - 09:58
    +2

    A lot of fear mongering about OBD scan tools. What do you think the professionals use? An OBD scanner!

    So long as the buyer only reads the data and doesn't do any calibration or changes there won't be a problem. If you don't trust the buyer to do that then you probably shouldn't be letting them test drive either.

    • zeomega on 10/06/2014 - 10:15

      Professionals use a proper OBD unit, not a elm327 type chip.

      It's like saying, a proper wood worker uses a table saw to cut wood, and so do you! When in actual fact you're using a cheapie ozito to cut a log where they use a proper full fleged industrial table saw.

  • PETEX on 09/06/2014 - 10:12

    If you are the seller and you read something like this

    http://www.extremetech.com/extreme/132526-hack-the-diagnosti…

    what would you do?

    • victorwilson on 09/06/2014 - 21:04

      Sounds concerning. I guess it depends how much the seller trusts the buyer.

  • Azn310 on 09/06/2014 - 23:07
    +2

    using OBD2 scanner to test used vehicle is perfectly fine. I would explain to the owner of the vehicles what I am doing and if he / she is comfortable with it.

    However, that bluetooth device that you show in the link is not safe for vehicle use. I have heard from mechanics that they sometimes cause a problem, especially on modern tech-loaded cars like the Europeans. Why? Because nowadays ODB2 is no longer a one-way report port, it actually let your car's brain interacts with the device to fix problems. So a device can do a lot of things, like turning off the cars fuel pump etc. Imagine if there is a miscommunication between your phone and the ECU..

    Best to invest in a more expensive OBD2 scanner, like Innova or Actron on Amazon. Autel is also a Chinese brand, best to stay away. IMO, if I were to sell my car, I wouldn't let the buyer plug in any cheap OBD2 device, it's just not worth it.

  • Mumbles on 10/06/2014 - 01:07

    I think the majority of owners won't be comfortable letting you attach anything to their car. Put yourself in the owners shoes. They are not knowledgable in car modifications or diagnostics. All they know is that any car problem will cost them thousands to fix. Based off that assumption its not worth the risk letting someone tinker with their pride and joy regardless of what is being said. There are other buyers who will come along who won't risk the car's electronics.

    With their lack of knowledge I wouldn't be surprised if they thought you were trying to defeat the car's immobiliser system.

  • lplau on 10/06/2014 - 09:19

    I think the only problem would be…. If the seller was already dodgy to begin with, and then let you use the OBD device.

    Then afterwards start blaming you for issues with the car.

  • fredz0r on 10/06/2014 - 09:30
    -3

    Why don't you just take the car on a test drive (by yourself) and when your around the corner do your test then. Seller doesn't even have to know….

    • Diesmile on 10/06/2014 - 09:37
      +2

      What? are you assuming you can test drive a car without owner sitting next to you when you are buying privately? lol

      If I am selling my car privately, I won't even let them test drive, instead I will drive them around, so no one can crash my car and walk away

    • victorwilson on 10/06/2014 - 11:50
      +2

      I'd rather be honest. Honest buyer + honest seller = smooth transaction.

  • matt_will_fix_it on 10/06/2014 - 09:58
    +3

    While you are inserting the OBD, also attach a GPS tracker and dashcam and mobile broadband device so you can track the car and check the owner doesn't speed or drive dangerously. You wouldn't want a car that has been abused either.

  • zeomega on 10/06/2014 - 10:09
    +1

    There is a chance the seller has a OBD and has cleared the fault codes as well. Not all fault codes pop up instantly. If you really want to know if you're buying a good car, get a proper mechanic. Obviously it boils down to economics of scale. You don't pay $150 for a $3k car etc.

  • Pacify on 10/06/2014 - 14:47

    If the owner refuses, dont buy the car. Its simple as that, theres no reason why any seller should deny you to be able to run any test you want, as long as u pay for it

    • gummibears on 11/06/2014 - 11:27
      +5

      I want to test if the car is fireproof.

  • t_c on 10/06/2014 - 14:53
    +5

    Love it when I'm selling a car and buyers rev the chit out of the motor when cold then make a low ball offer. Pure joy.

  • maybeamacy on 10/06/2014 - 14:54
    +2

    I programmed a spare key to my car with an OBD - how likely is it that a buyer could program a spare key to my card with an OBD and steal it later on? Slim but there's still a possibility haha.

  • MementoMori on 10/06/2014 - 21:29

    IMO you are over thinking your car purchase, IT style. An OBD scanner will not tell you many basic things, like the condition of the tyres, if the steering is out, if the exhaust is rusted through, etc.

    Just get a pre-purchase inspection from a mechanic - $150 or whatever.

    • Azn310 on 11/06/2014 - 14:27

      I think OP is asking beyond normal inspection of the car, not skipping the normal procedures. OBD2 does tell a lot about whats in the vehicle.

      Getting inspection mechanic would be great, but $150 would get me an OBD2 scanner that last my lifetime and full service for the vehicle I am purchasing. OZB style.

  • stumo on 11/06/2014 - 10:01

    Yeah. I wouldn't allow it. A buyer can easily flash program the ecu via the obd port. And suddenly its "oh noes, your car is faulty u need to drop the price by $4k because it needs a new ECU.

    Usually an obd fault will cause limp mode, so its kinda obvious if there is an obd readable fault with the car. If the mil light isn't on, there isn't much point reading the obd codes.

    • Azn310 on 11/06/2014 - 14:23

      What you say is very true indeed.

      However, I have an OBD2 scanner that actually does the State Emission readiness for cars in America (This is not required in Ozland). So it shows a bit more than diagnostic code, which is nice. For instance, it will show if the catalytic converter sensor (and a bunch of other sensors) is ready. I have never seen MIL light on in my car, but there were times the sensors just weren't functioning.

      Also, with a good OBD2 scanner, you get to see how the fuel pump and fuel filter is going, along with the coolant sensors, temperature sensors, without taking everything apart. Thats what inspection mechanics would do when they inspect the car for you anyways.

  • Shwayne on 11/06/2014 - 14:51

    As long as you're serious about buying the car, don't go OBD testing every car you come across.

    You can actually use one to CLEAR the defects, so that reading isn't actually going to do you much good.

  • MATTDAMON on 11/06/2014 - 16:34

    Any code will generally come with a CEL, so reading the OBD is useless (unless of course you have access to the manufacturers program which you wont, but then you can pull data such as hours switched on, max speed/max rpm etc)

  • steviee on 17/06/2014 - 13:30

    how would any of the information available assist with the purchase of the car ?

  • pegasusx on 09/02/2019 - 19:42

    Wow cant believe this came up in the search. I am about to do just the same thing when buying a used car. With OBDII you can pretty much access cleared Fault codes if you have the right software. Currently using free DDT4All + DT2000 DB to access all the ECU details for inspection. (Yes. You can do nasty stuff if you dont know what youre doing)

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