Simplest OBD reader for double-check mileage?


I’m a simple consumer considering to buy a test car (demonstrator vehicle), yet I’d really like to double-check the real mileage (from the ECU).

Also, would be great to be able to lookup any past error codes if any.

What is the simplest OBD reader option I can go for? Can I do this with a bluetooth interface with any free app?

(I searched the web, but most articles/videos shows live RPM display and current errors only)

Test car ? Don’t you mean a used vehicle ? Mileage rollback is just not that common anymore . This is where a Carfax report might help by showing past odometer readings . And if the vehicle is more than 10 years old it might be mileage exempt so the condition is what you need to be aware of and avoid anything will a rebuilt title .

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The phone apps I know that will provide the ECU mileage info is ForScan and it primarily works with Ford and Mazda vehicles and OBDEleven which works with VW and Audi vehicles. Neither cover all vehicles.

I have a couple more… Torque Pro and OBD Fusion and neither provide that.

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I’d be surprised if an OBD II reader would provide more accurate mpg estimates than the car does, it’d be using the same information.


Is there something that works well with Hyundai models?

Thanks for getting back! It is a new car (Hyundai i30 1.5 DPi) in a dealership used for test drives. I just want to be sure about the parameters, I thought an OBD reader could help me out.

I saw somewhere (can’t find the video now) that a car mechanic readed mileage from 6-8 various modules, and concluded that they are matching up. I thought that I could do the same somehow (?) with an app that have a similar template.

The OP wants to confirm the actual # of miles on the car to make sure the odo hasn’t been altered… read the miles from the ECU and compare to the instrument cluster.

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No suggestions, a web search would be your best bet.

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In the US of A that is called a demonstrator vehicle and it would be illegal to roll the mileage back. Also it will still have the factory warranty but I suspect you are not in the US . So I think you are worrying about something for no reason.

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Ah, my mistake. But wouldn’t the same still be true? Is there more than one ‘miles’ stored away in the ECU, one ‘real’ and one for display?

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For my Hyundai, I use a generic OBD to Bluetooth dongle that I got on Amazon for about twenty bucks. It sends the data to Torque Pro on my cellphone. It does provide the mileage stored in the ECU, but I have no idea if it will recover erased fault codes, since I don’t have any.

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Yes there is. The ECU has the correct mileage and the instrument panel carries its own to display. There may be other moduIes that save mileage as well on some cars.

I swapped instrument clusters in my Mustang to get a fancier dash from one year newer car. I had the mileage matched in the instrument cluster to my ECU so they would both read the same…or very close…I couldn’t get it perfect.

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That may be very well the case. Why would they risk?

Anyway, I think I should record the mileage into the agreement.

Thanks for pointing this out.

+Thanks people for all the inputs, :raised_hands: such a great community!

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That should be done on the title unless what ever country you are in does not do that . They will note the mileage so the warranty can verified . If you are this worried then buy completely new and not a demonstrator vehicle.

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Harbor Freight offers a bunch of code readers. Their website usually has a link to the user manual, so you can learn quite a bit about each of the product’s functionality from reading that.

For example I surfed to, typed “code readers” into the search box, and clicked on the first one in the list (ZR 13S). Halfway down that page, on the right is a link to a pdf version of the manual.

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I’m ok if the car is used and have some mileage count, I only want to pay the proportionate amount of money, though (as you said, Hyundai have 5 years warranty anyway). Same for error codes.

On Volvo you can open the console on the computer OBD II reader application and type in a binary/hex command that’s on somebody’s website on the Internet somewhere which retrieves the milage from the cluster. In theory it would work on any vehicle with an OBD II reader with a console, if you know what command to enter.