If you’re into cars and want to find out what that ‘check engine’ light really means, or much more, then you need an OBD2 scanner. Here’s everything you need to know, and whether you should go hand-held or wireless.
Imagine you’re in the outback, far from home. You get in your car, and switch the engine on, but it turns over and dies, leaving you with just a a familiar but unwanted light on the dash. You’d better find out what’s going on, because otherwise you’re stranded. Or imagine you’re at a racetrack, hot-lapping your daily driver sports car. You come in off the track, cooling the car and your nerves, but you see that nasty light saying there’s a problem. That needs diagnosis and fixing before the next session in only an hour when conditions will be right for that personal best.
Maybe you don’t even have a problem but you do want to see what your car’s doing, access some information like oil temperature, mileage since the last DPF burn and make yourself a real-time display, or data log. Or maybe you want to overlay data like gear, revs and speed on a video of your best hotlap.
You can do all this and more with the right OBD2 scanner.
If you’ve ever spent much time around cars you’ll be familiar with a CEL, or Check Engine Light, or one of many other interesting, but vague lights that appear on your dashboard to inform you that Something Is Wrong, but not what. Your owner’s manual will be similarly vague, suggesting a trip to the nearest dealer, pronto.
But there’s an easy way for you to find out what’s actually wrong, and that’s to scan your car’s electronic brains, or as they’re properly known, the ECUs (Electronic Control Unit) or ECMs (Electronic Control Module) using an OBD2 scanner.
What is OBD2?
Ever since cars began to feature microchips in the 1970s, manufacturers have needed a way to connect computers to the car’s ECU and read the information within. As you can imagine, to begin with every carmaker had a different way to connect, but eventually one common standard emerged from the Society of Automotive Engineers (SAE) and that was OBD, or On-Board Diagnostics. The SAE standard specified a physical connector and commands to read ECU information, specifically DTCs or Diagnostic Trouble Codes.
The SAE released OBD2, the second version of the OBD specification, and in 1996 the United States made it mandatory for all new cars to be fitted with OBD2 ports. That meant that many carmakers fitted them to the models destined for the rest of the world for cost effectiveness. In 2001 the European Union followed suit, mandating the very similar EOBD (Euro) standard, but it took Australia and New Zealand until 2006 to demand their petrol cars were OBD2 compliant, and 2007 for diesels. The relevant ADR is ADR 79/01 Emission Control for Light Vehicles, 2005. Japan also has a version of OBD2, JOBD which again is very similar to OBD2.
Your car’s OBD2 port will be somewhere around the driver’s area, usually between the steering column and the pedals. Below are my three cars to give you and idea. Sometimes you may need to remove some trim, for example in the Ranger PX you have to pull the driver’s side storage compartment down.
How do you use an OBD scanner to read your car’s ECU?
You’ll just need an OBD2 scanner, and there are two basic types. You can buy a Bluetooth OBD2 reader, plug it into your car, then run an app on your phone or tablet, connect via Bluetooth and read your car’s data. Or, you can buy a handheld scanner that you simply plug in to the port and all you then need to do is read the screen and press a couple of buttons.
The app method is the most feature-rich as you’ve then got a powerful smartphone with a high-resolution colour touch screen that can look up diagonistic codes and display all sorts of data. You can also read OBD data without a physical cable, just using Bluetooth. But, the app method requires you to have a smartphone and connect via Bluetooth. So if you want something simpler and more robust, just use a handheld scanner which is literally plug in and read, doesn’t rely on a fragile smartphone or Bluetooth, but won’t have as nice an interface or the benefit of an Internet connection.
If you go for the app method then there are a huge range of OBD2 adaptors to choose from. I’d recommend one that’s very small so it can stay in the car all the time and doesn’t get in the way when trim panels are replaced, and definitely not an el-cheapo as I have seen them have problems. A good one is only about $60 so trying to save $20 just isn’t worth it. And don’t bother with the WiFi versions, Bluetooth is much easier to set up. There’s lot of good apps to use; two I use are Torque Pro (Android) and Carscanner (Android and IOS), and below you’ll see my review of the Autophix products.
Once you’ve connected your scanner, app or handheld, the next step is identical. You press a button or tap an icon to read the fault codes, which takes a several seconds. The scanner then displays what it’s found. The code will start with one of our letters – P for engine and transmission (powertrain), B for body, C for chassis, and U for network (CANBUS or other data communications system within the car).
As an example, on my 86 I had a check engine light which came on above 6000rpm when not at full throttle. I used a Bluetooth adaptor I bought from Jaycar with the Torque Pro app to scan the car. Torque Pro automatically looked up Troublecodes.net and showed me all I needed to know about the error code which was P0351, invaluable information so I knew whether to keep driving the car or panic.
Here are some examples of error codes cars might throw up, and you can see how useful that information would be:
- P0127 – intake air temperature too high;
- P0148 – fuel delivery error;
- P0169 – fuel composition incorrect;
- P0635 – power steering circuit malfunction;
- C0020 – ABS Pump Motor Control;
- C0049 – Brake Fluid Fault;
- B1410 – Driver Power Window Circuit Failure; and
- B1900 – Driver Side Airbag Fault.
Now all that’s standardised in the SAE’s specification, last updated in 2016 so it now includes codes for hybrids. Unfortunately, many codes are left open to the manufacturer and naturally each one has used the same code for different purposes. This means your scanner will read all the standard codes, but to get the best from any specific vehicle it’ll also need to understand that manufacturer’s specific codes which isn’t a given if you use a generic scanner. The best scanner for your vehicle is one which is made to understand all your carmaker’s specific codes – an example is Forscan for Ford/Mazda, JScan for Jeep and Nanocom for Land Rover. However, these specialised units may be more expensive than a generic scanner.
So you’ve got the fault code up on the scanner. You may need to do some more diagonsis, but at least you know where to start. Your basic options are now:
- Clear the code and just carry on – if it’s caused by something you know isn’t a problem, or maybe an intermittent code caused by a set of control inputs you can avoid or not use, or you just really need to keep going. But don’t just go clearing codes and forgetting, they’re there for a reason.
- Fix the root cause – complete diagnosis and fix whatever caused the code in the first place.
- Stop driving – if it seems like a dangerous problem and it’s unsafe to proceed.
Just knowing what the fault is could save you. Let’s say you have a C0023 Stop Lamp Control fault. You’re not going to worry about fixing that urgently. But, you would want to know about P00012, camshaft over-retarded. And even if you can’t fix the fault or understand it, you can at least quote it to someone who can help instead of just saying “funny light on my dash”.
Autophix OBD2 Scanner Reviews
I’ve got two OBD2 scanners on test from Australian company Autophix Australia and have used them my Subaru Forester SH, Ford Ranger PX and Toyota 86 including deliberately generating engine error codes to see if they would detect and clear the codes. That worked on all three cars, with both scanners.
Autophix 3210 Review
This is a Bluetooth OBD adaptor that you use with the companion OBDMate app for Android or IOS. The 3210 is $129.95 retail and the app is free. The adaptor itself is not the smallest on the market, but should still be small enough to tuck up behind trim panels so you can leave it permanently connected. A good feature is a little blue light which tells you its connected – wish all the others had that.
A downside is that the adaptor works only with the OBDMate app; so you can’t connect the adaptor to your favourite OBD scanner software, or programs such as RaceChrono or Harry’s LapTimer.
The OBDMate app works only with the 3210, and aside from reading and clearing fault codes has a wide range of features. There’s a trip meter, acceleration measurement test, highly customisable dashboard display so you can pick what information you want displayed and how, battery check, head-up display feature (HUD) and much more. Despite all that, it’s still behind the likes of Torque Pro and Carscanner for breadth and depth of features; for example it can’t integrate with video, send information via social media or data feeds to Excel, use a voice or sound recording for alerting, create custom PIDs (manufacturer-specific codes), and there’s no video function.
However, my guess is almost all users will find OBDMate’s features more than they will ever use – it will read and clear codes which is what you buy these things for, and much more beyond that.
The major advantage of the 3210/OBDMate is the all-in-one system and one-stop support. Every other system I’ve seen is buy the adaptor, buy the app separately, and generally they work but if not, that’s tough. With Autophix you have the advantage of both being by the same company, and local support in Australia by an Aussie company.
Autophix OM126 Review
This is a a hand-held unit with a RRP is $149.95. It’s relatively small, very robustly built and simple to use. Plug in, read the codes, clear the codes.
There’s some other functions such as emissions tests and vehicle information readouts, but realistically I can’t see many people using them and if you want that sort of feature, you’re better off using an app which can do all of that more cheaply, easier and with more features than a handheld unit. The advantage of the handhelds like the OM126 is that you could store this one away for years in a toolbox then pull it out and use it – try doing that with a smartphone. There’s also the Autophix OM123 which also has the basic read/clear code function for $84.95 but has a more basic LCD screen.
Why I’m convinced about OBD scanners
I have Bluetooth OBD2 scanners in all my cars, all the time, permanently connected. I do that not because I generally look at the interesting displays I can create on my phones, but because if there’s a problem with my car or another then I can at least diagnose it. Over the last few years I’ve had plenty of reason to use my scanners; clearing a fault code on an overheated WRX CVT transmission at a racetrack, my own 86’s ignition error, a Jeep with an ABS fault and a Nissan with a transmission fault. A Bluetooth OBD2 scanner costs around $50 and the apps are less than $10, so, very cheap, fit-and-forget insurance that I think no car enthusiast should be without, and nobody should be heading off into the outback without one. You should consider a more specialised scanner specific to your car if you’re going to do an extended Outback trip or modify your vehicle.
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