Cheap OBD diagnostic equipment?

Why don’t more people who work on their 96+ vehicles that are having issues immediately consider this. Readers that poll data and send it to a laptop or cell phone are cheap and readily available. I mean OBDlink starts at like 30$ and who knows what other stuff is out there. The information they provide is invaluable. Is it really not that well known?

I use the Torque app for Android and a $15 OBD bluetooth dongle. Works great and displays about all the info you can imagine.

Many people don’t utilize these because having the information isn’t enough to get the job done. You need to know what to do with the information. A quick scanner will mention a sensor and an inexperienced person will just replace that sensor just to find that it didn’t solve the problem. I wonder how many 02 sensors and catylitic converters have been mistakenly replaced.


The torque app only goes so far. It won’t help with ABS or SRS codes. Just the basic engine codes. But as @tcmichnorth points out… reading the codes is one part… understanding the total picture is important.

There are low cost apps for specific cars, Forscan for Ford, OBDeleven for VAG vehicles. Lots more functions. Also cheap.

Consider how many people who post here that they have changed the battery, alternator and starter because the CEL is on. And without even owning a voltmeter to check the basics.

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As others said, you have to know what to do with the data

What are normal values?

What are abnormal values?

Does the data even correlate to your complaint?

I’ve known professional mechanics that don’t even know what they’re supposed to be looking for

Do you know what values a map sensor, maf sensor, upstream- and downstream-oxygen sensor is supposed to have? Do you know the difference between open loop and closed loop? Do you know what limp mode and reduced power are? Do you know the difference between short term and long term fuel trim values? Do you know what a fuel trim cell is?

And that was just VERY basic stuff

Do you know what to look for, when it comes to cylinder shut off, variable cam timing, and so forth?

Do you know how to diagnose evap systems? Do you know how the systems work, how they test themselves, etc.?

What about if you’ve got a hybrid . . . ?!


Some folks make things happen

Some folks watch what happened

Some people wonder what happened

Some folks disconnect the battery (more than once) to reset the CEL, these folks would be hopeless with a code reader


I agree code readers are fairly useless alone. My point is it’s all pretty standard data. Fuel trims, coolant temps, O2 readouts. I can plug in a 3.0 duratec and tell you within a minute what bank is misfiring, and exactly why and I have only been working with this tool for less than 3 years. The way they present data is super easy to understand. It’s all converted to degrees and percents.

I disagree

There’s plenty of very useful pids that a cheapo scanner, code reader, etc. will NOT give you


For basic engine diagnostics the standard OBD2 PIDs are extremely valuable to anyone scratching their head over an intermittent misfire or hesitation under load with no CEL or why it idles rough in cold weather. This is just my experience with things.

Agree! A perfect situation to take the car to a professional equipped with a professional scan tool, especially if there is no CEL! The cheap tools can sometimes point you in the right direction if you know what you are doing and the problem no so complicated. Their live scanning abilities leave a bit to be desired.

I like strip charts that display several PIDs in at a time. That takes a decently big display (8 inch tablet) and a fairly powerful tablet to process. But that is still no substitute for a pro scanner.

From someone who has used not just a general OBD2 to USB cable but also specialized cables like a ft232 for data logging while tuning I can tell you that you are really giving much of this expensive “professional” equipment too much credit. With the exception of manufacturer specific applications which in most cases you would only find at a dealership service center I haven’t seen anything an expensive scan tool can log that I can’t. Knock sum and MDP output are the only reasons I bought the ft232 and that’s only because my ECU was only designed to send that data over MUT.

This is not about data transmission speed. This about access to vehicle or manufacturer specific PIDs.

Take your Torque Pro to any Ford with a 6 speed auto trans. Find the transmission temperature output. You must have that temp to check the trans fluid temp is high enough when checking the fluid level. Go on, check. I can tell you it isn’t there. Now run a data stream on the left front wheel ABS wheel speed sensor for any car or truck. Torque can’t. It cannot communicate with the ABS. Same for the SRS.

Now stop and ask any professional shop with a $4000 scanner and a subscription service if they have access to Ford’s trans temp. They do. These are not dealer only PIDs. They are Ford PIDs not accessable by many apps. Forscan has this access but it won’t help you with a Chevy.

As we’ve been trying to tell you, the cheap phone app tools do not have access to a lot of data floating around on the car’s network.


At no point did I mention data transmission speed and I have never used a Torque pro nor did I mention it. I also never mentioned information in regards to the transmission. I said engine operation and have only referenced issues pertaining to engine operation. I also thought I clearly mentioned manufacturer specific applications somewhere in there. Not every professional shop can afford a 4000 piece of equipment and a subscription so yeah, a dealership is where you are more often than not going to find that sort of thing with exception to a shop that specializes in one or even a few makes. Look I dont know why your making such a big deal about this. I never said they where the holy grail of tools. I was only trying to make the point that for 30$ they provide a lot of useful information.

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A shop that does claims to do diagnosis which can’t afford a $4000 professional level scanner . . . something tells me maybe they shouldn’t advertise that they can do diagnosis :thinking:

That’s like saying your shop can do tires, but all you have is tire spoons . . .

I don’t even own a shop, yet I’ve got a roughly $4000 scanner . . . I think it was about $3800 for the scanner, plus a few hundred for the european software, plus software updates every year for several hundred dollars


Okay, nobody said anything about advertising anything. It’s obvious you two are just trolling. I guess thank you for killing time with me.

I’m not trolling you

Just pointing out that this free data isn’t the same thing as having a professional level tool . . . and all the free data in the world isn’t going to give you the knowledge and experience to know what you’re looking for, how to process the data and so on

I’ve seen a lot of guys show the data they’ve retrieved, but they don’t know what it is, how to interpret it, and so forth. Plus, as @Mustangman said . . . they literally don’t know what they don’t know. They aren’t aware that some of the most important pids aren’t even being displayed on their device

it’s as if I were to try to become a licensed plumber tomorrow. I literally don’t know what I don’t know. I would have no clue how inadequate and/or wrong I was

I’m working with a young guy at work these last several weeks . . . he throws around a lot of technical terms, but I’ve seen right through it and realize he doesn’t actually know what he’s doing. He doesn’t even know what to look for, much less interpret it, if he does see something. He’ll eventually gain experience, but I frown upon guys bragging about how smart they are, when in fact they couldn’t even diagnose a flat tire. He constantly asks me for advice, and I tell him what I’m doing, why I’m doing it, and so forth. I even told him what websites he can access for free, so that he can try to learn this stuff on his own time. I’ve even showed him the website, for goodness’ sake. Yet he hasn’t done it, and he’s told me so. If you can’t . . . or won’t . . .help yourself, then that might mean you’ll continue being blissfully ignorant

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Dude, I’m talking about basic information here and had expressly narrowed the conversation hours ago to avoide any confusion. In my initial post I wasn’t comparing it to anything. I never described it as a professional anything nor did I attempt to glorify it. I’m really quite confused as to what you gained by comparing 30$ and a + 1000$ products. I’m only going to say it again because it seems as if your missing the point of all of this. If people really care enough to ask why don’t they use it and learn?

I would expect any licensed professional shop to have access to professional-level tools, including professional scan tools. I would not expect a professional mechanic to use a $100 Harbor Freight scan tool, or equivalent, any more than I’d expect a DIY’er to invest $3000+ to buy a factory scan tool.

Also, most of the really cheap “OBDII scanner tools” costing $50 or less are useful for little more than viewing and erasing trouble codes, and seeing if enough of the emissions monitors have “set” to pass a state emissions test. Few of these really cheap tools can display any live data, or freeze frame data. Of course, even a DIY’er scan tool costing $60-150 cannot display nearly as much information as a professional-level scan tool, and few scan tools costing less than $500 will let you run bi-directional tests.


YOU are the one who bragged that your stuff can pretty much do everything the professional level tools can

Let’s quote you . . .

I’ve seen lots of cases where guys try to properly diagnose a car with non-professional scanners and equipment . . . and it simply couldn’t be done, because the tools didn’t display the stuff they needed and they weren’t capable of running the tests and functions that were needed to properly diagnose and fix the problem(s)

And these vehicles I’m thinking of weren’t exotic, luxury, sporty or anything along those lines. They were Fords, Chevys, Toyotas, and other such common vehicles.


Come on now, this guy is obviously a troll. If a $30 Bluetooth OBDII reader could really do the same thing as a $3000-4000 professional scan tool–or even a $150 DIY’er scan tool–then what fools we must all be for spending more than $30 on a scan tool. That is like saying a set of Pittsburgh wrenches from Harbor Freight Tools is as good as a similar set from Snap-On costing 10 times as much.

Only an idiot would believe that, however the Pittsburgh set may very well be adequate for home use. In fact, I have many Pittsburgh automotive tools at home, including impact sockets, Torx sockets, Allen sockets, breaker bars, ratchet extensions, pulley pullers, disc brake service tool set, and so on. I am of course, not a professional mechanic, and these tools are used strictly for working on my personal vehicles. For my actual job, which is HVAC, I have NO Harbor Freight tools of any kind. I use professional tools for my professional job.