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The best OBD-II scanners in 2021

Included in this guide:

Best OBD-II scanners: SeekOne SK860 displaying main menu
(Image credit: Tom's Guide)

Need to save money on car upkeep and repairs? Stashing one of the best OBD-II scanners in your glove box or trunk may be crucial in those moments when your car's Check Engine light suddenly comes on, and you're on a lonely country road or just a week shy of getting the vehicle inspected.

Each on-board diagnostics (OBD) scanner plugs into an access port near the driver's seat and taps into the car's computer systems. It can tell you whether your Check Engine light is caused by an easily replaceable gas cap or by a faulty catalytic converter that's going to cost $1,000 to fix.

OBD-II scanners, sometimes written as OBD2 scanners, or EOBD scanners as they're called in Europe, also let you see what's going on with your car's engine, transmission and other critical systems — information that normally only your mechanic has access to.

Whether you're taking your ride into the shop for a routine checkup or for a major repair, knowing this vital information will prevent you from being bamboozled into green-lighting unnecessary fixes. 

In fact, once you know everything that's going on with your wheels, you can end up doing a lot of the smaller stuff yourself. That makes the best OBD-II scanners — which range in price from $25 to $200 — pay for themselves.

We've tried out and tested more than a dozen OBD-II scanners, and we've rated them based on features, size, warranty, setup, ease of use and — above all — value. The best OBD-II scanners can diagnose thousands of automotive problems. 

OBD-II/EOBD scanners work on almost all passenger vehicles sold in the United States since 1996, in Canada since 1998, in the European Union since 2004, and in Australia, Mexico and New Zealand since 2006. (Here's how to find your car's OBD-II port on North American cars, and here's how to find your OBD-II/EOBD port worldwide.)

Not all the best OBD-II scanners are created equal. There are two general types of devices.

  • Handheld OBD-II scanners come with their own screen and cable to plug into the car's OBD port.
  • Wireless OBD2II scanners plug into the port, but then connect via Bluetooth to a smartphone or tablet to display their findings.

Whichever type of device you choose, there are several high-performance OBD-II scanners that cost less than $200. A couple are less than $30. One of the best OBD-II scanners is no longer an unaffordable luxury, but something you need to have in your car. 

What are the best OBD-II scanners?

The best OBD-II scanner we used and tested is the Innova CarScan Inspector 5310. It has a color display, delivers a ton of useful data, shuts off the oil-change light and can run your car through a pre-inspection test. Unlike most scanners, it has both a handheld screen and the ability to connect to an app on your phone via Bluetooth.

The Innova provides code definitions to help you easily identify car problems and the Repair Solutions2 app helps you get verified fixes and will give you the exact parts you need, recall info and more.

The Topdon ArtiDiag500 is our second Editor's Choice. It has an unusual horizontal screen, has a full complement of functions and abilities, and is one of the few scanners that can connect to Wi-Fi.

The BlueDriver Pro Scan Tool is our top pick among Bluetooth-only scanners. It's a thick stubby plug that you can leave connected to your OBD-II port, but the app is elegant and well designed.

If you have a GM, Ford, Chrysler or Toyota car from the '80s or early '90s in your driveway, Bosch's OBD 1300 might be a godsend. It comes with specialized cables to connect to those pre-1996 "OBD-I" models.

Ancel's BD310 is another great OBD-II scanner. It does double duty by providing a small but efficient cabled handheld scanner for nosing around under the hood, and it can also wirelessly receive OBD data to serve as an auxiliary gauge inside the cabin to display key engine parameters. It's quite affordable.

See all of our picks for the best OBD-II scanners below.

The best OBD-II scanners you can buy today

Top Pick

(Image credit: Tom's Guide)

1. Innova CarScan Inspector 5310

Cheap, easy to use and offers repair suggestions

Specifications
Display/size: Color/2.8 inches
Bluetooth/handheld: Yes/Yes
I/M Readiness test: Yes
Displays live data: Yes
Number of keys: 9
Warranty: 1 year
Size: 6.9 x 3.4 x 1.2 inches
Weight: 10 ounces
Reasons to buy
+Great value+Resets oil light+Offers repair instructions and part pricing
Reasons to avoid
-Interface can be confusing-Lacks high-end features more expensive scanners have

The Innova CarScan Inspector 5310 beats its predecessor, the Innova CarScan Advisor 5210, by adding the ability to reset the oil-maintenance light. Like the 5210, the 5310 has the ability to provide readouts via Bluetooth as well as through a cable.

At $140, the Innova CarScan Inspector 5310 has all the features you would want from an amateur mechanic's OBD-II scanner. Its 2.8-inch color screen displays everything from live data to fault codes to a pre-inspection I/M readiness check.

If you'd rather use your phone, the Innova CarScan Inspector 5310 can connect via Bluetooth to the Innova RepairSolutions 2 app on an iPhone or Android phone. The app adds maintenance schedules, service bulletins and predictive-failure warnings.

The Innova CarScan Inspector 5310 may not have it all, but it should satisfy most weekend mechanics short on time. It's one of our two Editor's Choices.

Read our full Innova CarScan Inspector 5310 review.

Best OBD-II scanners: Topdon ArtiDiag500 displaying diagnostic trouble codeTop Pick

(Image credit: Tom's Guide)

2. Topdon ArtiDiag500

The best sub-$200 OBD-II scanner on the market

Specifications
Display/size: Color touchscreen/5-inch
Bluetooth/handheld: No/Yes
I/M Readiness test: Yes
Displays live data: Yes
Number of keys: 4
Warranty: 2 years
Size: 9.1 x 4.9 x 1.4 inches
Weight: 1.6 pounds
Reasons to buy
+Excellent array of diagnostic tests+Wi-Fi connectivity+Rugged design with soft edges
Reasons to avoid
-Heavy and cumbersome-Short cables

The Topdon ArtiDiag500 straddles the line between amateur and professional users with a large color touchscreen, Wi-Fi and an automotive health report. 

It looks like a rugged portable gaming console, feels like a brick and has a 47-inch cable that won't quite reach the engine bay (and won't fit into the carrying case when attached to the unit). 

Despite that, the Topdon ArtiDiag500 is one of the most capable consumer-grade OBD-II scanners we've seen. It can monitor the brakes, airbags and battery, run an I/M pre-inspection test and also display and graph live car data. The Android-based unit has its own rechargeable battery and can update its own software, two things you don't often see on handheld scanners.

It may be big and heavy, but the Topdon ArtiDiag500 might be the best $170 a car owner can spend on an OBD-II diagnostic scanner.

Read our full Topdon ArtiDiag500 review.

(Image credit: Future)

3. BlueDriver Pro Scan Tool

Full-featured and easy to use

Specifications
Display/size: None
Bluetooth/handheld: Yes/No
I/M Readiness test: Yes
Displays live data: Yes
Number of keys: None
Warranty: 1 year
Size: 2.2x 1.9 x 1.0 inches
Weight: 2.4 ounces
Reasons to buy
+Offers repair suggestions+Can read enhanced codes+Excellent phone/tablet app
Reasons to avoid
-Large transmitter-Specialty monitors don't work with all vehicles

The BlueDriver Pro Scan Tool is one of the most thorough Bluetooth-based automotive scanners, combining access to both basic and manufacturer-specific faulty codes and providing advice on how to fix problems.

The physical device is rather large, but that makes it easy to plug it into or yank out of an OBD-II port. An LED on the device lets you know whether it's in operation or in fault mode.

The BlueDriver mobile app is user-friendly and well laid-out, displaying data in automotive-style gauges and letting you export data to a spreadsheet. There's an I/M readiness test called a Smog Check, diagnostic tests for anti-lock brakes and engine timing, and Mode 6 in-depth diagnostic testing, although the amount of data collection may depend on your car's model and year.

Read our full BlueDriver Pro Scan Tool review.

(Image credit: Tom's Guide)

4. Bosch OBD 1300

The diagnostic scanner to get for older cars

Specifications
Display/size: Color/3.5 inches
Bluetooth/handheld: No/Yes
I/M Readiness test: Yes
Displays live data: Yes
Number of keys: 8
Warranty: 1 year
Size: 6.8 x 2.6 x 1.0 inches
Weight: 10.5 ounces (1.4 pounds with 84-inch cable)
Reasons to buy
+Comes with cables for pre-1996 vehicles+Includes repair suggestions+Can reset oil-change light
Reasons to avoid
-Can get heavy despite small size-No manual or quick-start guide

The Bosch OBD 1300 diagnostic scanner stands out by including cables to connect with pre-1996 Chrysler, Ford, GM and Toyota cars. It can get heavy once the 6-foot extension cable is attached, but the OBD 1300's small size hides its powerful range of abilities.

Unlike many handheld diagnostic scanners, the Bosch OBD 1300 doesn't get power from your car's OBD-II port. Instead, it uses AA batteries or your car's cigarette lighter to power its large color screen, which shows graphing data clearly. 

The scanner's database holds details on 26 million repair suggestions. It can check the anti-lock brakes and air bags on most cars released from 1996 to 2013, monitor the charging system and battery and run a pre-inspection emissions test. You'll need to get the instruction manual from Bosch's website.

With a list price of nearly $200, the Bosch OBD 1300 may seem expensive until you see how many cars it can work with. It's the diagnostic scanner to get if you have an '80s or early-'90s car.

Read our full Bosch OBD 1300 review.

(Image credit: Tom's Guide)

5. Foxwell NT614 Elite

Like having a Nintendo Switch to diagnose your car

Specifications
Display/size: Color/4.3 inches
Bluetooth/handheld: No/Yes
I/M Readiness test: Yes
Displays live data: Yes
Number of keys: 7
Warranty: 1 year
Size: 7.8 x 3.8 x 1.2 inches
Weight: 1.1 pounds
Reasons to buy
+Nearly complete array of diagnostic tests+Rugged design with soft edges+Includes hard case and SD card
Reasons to avoid
-Won't run on battery power-No touchscreen

Foxwell's NT614 Elite diagnostic scanner squeezes a large color screen into a small, rugged horizontal case. It's powerful and can probe many car problems, but we wish it had a touchscreen and could run on battery power.

Like the similar-looking but bulkier Topdon ArtiDiag500, the Foxwell NT614 is aimed at professional mechanics as well as car owners. It can graph data, cancel the oil-change light, and monitor the charging system, air bags, brakes and transmission. 

Two unique features stand out. Like a gaming keyboard, the Topdon ArtiDiag500 has programmable keys that can be set up to do different things with different makes of cars. It also has a microSD card slot for data storage. It may be the OBD-II scanner to have if you do a lot of work on cars from different manufacturers.

Read our full Foxwell NT614 Elite review.

(Image credit: Tom's Guide)

6. ThinkCar ThinkDiag TKD01

Dependable, but you've got to pay an annual subscription fee

Specifications
Display/size: None
Bluetooth/handheld: Yes/No
I/M Readiness test: Yes
Displays live data: Yes
Number of keys: None
Warranty: 1 year
Size: 3.1 x 2.0 x 1.1 inches
Weight: 2.7 ounces
Reasons to buy
+Reads enhanced codes+Lots of optional abilities available+Comes with hard case
Reasons to avoid
-App subscription costs $40 after first year-Heavy and hard to install

The ThinkCar ThinkDiag TKD01 is among the largest Bluetooth-based OBD-II automotive diagnostic scanners. It can show you extended fault codes or turn off the oil-change light, but be wary of the annual app-subscription plan.

At more than three inches across, the ThinkDiag is so big it won't fit into some OBD-II ports. You may need an extension cable to connect to your car's systems. On the upside, the rugged oval-shaped unit is practically indestructible.

The ThinkDiag app offers profiles for more than 100 automakers, letting you dig deep into manufacturer-specific codes. You get one profile for free for the first year, but after that each profile is $40 per year (and even more for Teslas). If you have multiple cars of different makes, you'll pay for each profile.

The app can turn off the oil-change light, check tire pressure, airbags and brakes, and predict which systems will go south soon. However, it doesn't tell you which replacement parts or repairs might be needed.

Read our full ThinkCar ThinkDiag TKD01 review.

Innova CarScan Pro 5210 (Image credit: Tom's Guide)

7. Innova CarScan Pro 5210

Puts more car data at your fingertips

Specifications
Display/size: Color/2.8 inches
Bluetooth/handheld: Yes/Yes
I/M Readiness test: Yes
Displays live data: Yes
Number of keys: 9
Warranty: 1 year
Size: 6.7 x 3.4 x 1.1 inches
Weight: 7.7 ounces
Reasons to buy
+Big screen+Lots of data+Repair explanations
Reasons to avoid
-Relatively pricey-Short cable

The Innova’s CarScan Pro 5210’s can tell you more about your car than many of its competitors, which is why it deserves to be among the best OBD-II scanners. 

The Pro 5210 scanner’s 2.8-inch color screen is bright and its narrow and long aspect ratio means it can squeeze in lots of automotive details, from fault codes to live data to a pre-inspection check. Its LED lights glow red for a permanent fault, yellow for an intermittent fault and green for no problems.

The CarScan Pro 5210 goes beyond displaying the expected fault codes with a Bluetooth connection to a phone or tablet and Innova’s Repair Solutions2 free app. The software explains the repairs and even the parts needed to fix the car. 

With a 9-key interface, the Pro 5210 is one of the easiest of the best OBD-II scanners to navigate. It found the fault I introduced to my 2014 Audi AllRoad and turned off the car's check engine light. 

On the downside, the CarScan Pro 5210 has a 27-inch cable, which is short, and its overall dimensions feel bulky, particularly compared to the smaller and lighter EDIAG YA-201. While pricey, the Innova CarScan Pro 5210 Pro 5210 is a must-have for those who want to know what’s wrong with their cars.

Best OBD-II scanners: Ancel BD310

Ancel BD310 (Image credit: Tom's Guide)

8. Ancel BD310

The best OBD-II that does double duty

Specifications
Display/size: Color/2 inches
Bluetooth/handheld: Yes/yes
I/M Readiness test: Yes
Displays live data: Yes
Number of keys: 4
Warranty: 3 years
Size: 5.1 x 2.4 x 0.6 inches
Weight: 5.4 ounces
Reasons to buy
+Small and light device+Designed as scanner and supplemental wireless car display+Can work as handheld scanner or with a phone
Reasons to avoid
-Minimalist interface-Small screen

Ancel's BD310 is just as good as a handheld scanner with a screen as it is when connected to a phone or tablet via Bluetooth. It can also augment the car's cockpit with a supplemental display of key engine parameters. Think of it as freedom-of-scanning choice.

Small and lightweight, the BD310 can live in your car's glove box. Its icon-based, 2.0-inch color display is a little skimpy but easy to figure out, regardless of whether you want an I/M inspection-readiness test or performance details, like coolant temperature, engine timing and engine speed. They can be shown as numbers or graphs.

It has a 56-inch cable that makes it just as good for hanging over the hood looking for an engine problem as monitoring the engine while driving. On the other hand, the BD310's rudimentary four-key interface can make navigation awkward. There's also a mode button on the side for selecting Bluetooth and cable operation.  

Read our full Ancel BD310 review.

Best OBD-II scanners: Autel AutoLink AL539

Autel AutoLink AL539 (Image credit: Tom's Guide)

A smart OBD2 scanner pick for diagnosing electrical problems

Specifications
Display/size: Color/2.8 inches
Bluetooth/handheld: Yes/no
I/M Readiness test: Yes
Displays live data: Yes
Number of keys: 8
Warranty: 1 year
Size: 6.7 x 3.6 x 1.4 inches
Weight: 10.6 ounces
Reasons to buy
+Includes electrical multimeter+Battery tests+Includes stand
Reasons to avoid
-Can't use OBD scanner and electrical meter at once-Need to recharge battery

Unlike most OBD-II scanners, Autel's AutoLink AL539 can check electrical connections with a built-in multimeter to uncover electrical shorts or burned-out cables. The device's lithium-ion battery powers it for checking fuses, the alternator's voltage or the gas gauge.  Just note that the multimeter doesn't work when the AL539 is connected as an OBD scanner.

The AL539 not only shows live data, like engine speed, coolant temperature and other items but also can run a comprehensive pre-inspection readiness test. It shows results as three lights for faults: red (permanent fault), yellow (temporary fault) or green (no faults).

Despite its soft rubber bumpers, the AL539 is fairly compact and light at 6.7 x 3.6 x 1.4 inches and 10.6 ounces. It has a unique pull-out leg so the device can stand on its own, as well as a generous 58-inch cable. Its bright, 2.8-inch color display has icons for major functions and an easy-to-follow, eight-key interface.

Read our full Autel AutoLink AL539 review.

Best OBD-II scanners: SeekOne SK860

SeekOne SK860 (Image credit: Tom's Guide)

10. SeekOne SK860

Get a large color screen and a lifetime warranty

Specifications
Display/size: Color/2.8 inches
Bluetooth/handheld: No/yes
I/M Readiness test: Yes
Displays live data: Yes
Number of keys: 8
Warranty: Lifetime
Size: 7.8 x 3.8 x 1.2 inches
Weight: 11.2 ounces
Reasons to buy
+Lifetime warranty+Rugged design+Icon-based navigation
Reasons to avoid
-Big and heavy-Few features you'll find on pricier scanners

Its large color screen, range of tasks, lifetime warranty and ease of use make the SeekOne SK860 a winner. 

The price for this is a handheld scanner that can feel bulky and heavy. Its soft rubber bumpers and rugged design mean you don't have to baby the SK860, and it comes with a 58-inch cord and bright, 2.8-inch color display. 

Its eight-button navigation scheme and icon-based interface are easier to use than budget scanners. The SK850 has a one-button I/M pre-inspection readiness check along with a green (no-fault codes), yellow (intermittent problems) and red (permanent-problem codes) LED scheme. 

The SK860 does much more than typical handheld scanners and comes with a padded case, but its lifetime warranty makes it stand out from the crowd.

Read our full SeekOne SK860 review.

(Image credit: thinkcar)

11. ThinkOBD 100

Small but powerful, the ThinkOBD 100 is a bargain

Specifications
Display/size: Color/1.8 inches
Bluetooth/handheld: No/Yes
I/M Readiness test: Yes
Displays live data: Yes
Number of keys: 4
Warranty: 1 year
Size: 4.7 x 2.6 x 0.8 inches
Weight: 5.6 ounces
Reasons to buy
+Small and light +Inexpensive+Shows live Data
Reasons to avoid
-Small screen-4-key interface

Small and inexpensive, the 5.6-ounce ThinkOBD 100 scanner is perfect for a quickie diagnosis, roadside repairs and running a pre-inspection test. However, it lacks the depth to explain deeper automotive problems.

The ThinkOBD 100 can disappear in a glove box and includes a USB cable for updating its firmware. On the downside, the scanner’s 1.8-inch screen is an inch smaller than many competitors and feels cramped. 

Its four-quadrant home screen is simple with entries for Diagnose, Lookup, Setup and Help, but the four yellow circles above do nothing. That leaves the rudimentary four-button keypad as the only way to interact with the scanner.  

In addition to displaying current fault codes, the ThinkOBD 100 shows live car data, like spark advance and engine speed, but it spreads the data over 38 pages. After I introduced a fault in my 2014 Audi AllRoad, this OBD-II scanner diagnosed the problem and I was able to turn off the Check Engine light. Unfortunately, I had to manually type the code into the Lookup section to find its meaning. 

The device offered no explanation or repair options, making it second best to more advanced (and expensive) handheld scanners, like the Innova CarScan Pro 5210.

Jethax OBD-II Scanner (Image credit: Tom's Guide)

12. Jethax OBD-II Scanner

Small and light, this OBD-II scanner makes it easy to connect

Specifications
Display/size: 1 LED
Bluetooth/handheld: Yes/No
I/M Readiness test: No
Displays live data: Yes
Number of keys: N/A
Warranty: 1 year
Size: 1.8 x 1.7 x 0.8 inches
Weight: 0.7 ounces
Reasons to buy
+Built-in flashlight+Easy to insert and remove from OBD port+Good Bluetooth range
Reasons to avoid
-No status LEDs

One of the easiest OBD-II scanners to install, use and remove, Jethax’s OBD-II Scanner stands alone with a built-in LED flashlight to illuminate the car’s diagnostic port. Its ribbed sides make it a snap to pull out.

The 1.8 x 1.7 x 0.8-inch unit is slightly bigger than Autel’s MaxiAP AP200 but at only 0.7-ounces, it’s significantly lighter. It has a single LED but it was always red.

The Jethax scanner uses Bluetooth 4.0 to connect to an iPhone, iPad or Android phone but lacks its own app. The QR code on the unit’s box points to several free diagnostic apps, including Torque Lite, which I used with my Samsung Galaxy S9 Plus phone.

After plugging the Jethax OBD2 Scanner into my Audi AllRoad’s OBD port and connecting the scanner to my phone, the app started showing live data. In addition to a series of automotive gauges and fault codes, the system can run acceleration tests.

The Jethax has a 28-foot Bluetooth range, which was on a par with other Bluetooth scanners. It found my introduced fault and turned off the check engine light. 

Don’t let its size or $35 price tag fool you. Jethax’s OBD-II Scanner not only tells what’s going on inside your car but lights the way to plug it in.

Best OBD-II scanners: Topdon ArtiLink 500

(Image credit: Topdon)

With many manufacturer codes, the Topdon ArtiLink 500 is versatile but lacks repair information

Specifications
Display/size: Color/2.8 inches
Bluetooth/handheld: No/Yes
I/M Readiness test: Yes
Displays live data: Yes
Number of keys: 8
Warranty: 1 year
Size: 6.6 x 3.7 x 1.1 inches
Weight: 10.2 ounces
Reasons to buy
+Big screen+Includes manufacturer specific codes+OBD plug light
Reasons to avoid
-Big and heavy

With many of the abilities of a professional OBD scanner, Topdon’s ArtiLink 500 does a lot for its $59 price tag.

Big and bulky, the ArtiLink 500 weighs 10.2 ounces and its 54-inch cable has a lighted connector at the end that helps with plugging the scanner in. The scanner can be updated using its included USB cable.

The ArtiLink 500’s bright 2.8-inch color screen shows fault codes, a pre-inspection readiness report and definitions of what its fault codes mean. The 8-key interface is efficient and lets you pick from the major categories. This OBD-II scanner shows live car data, can graph it and lets you print it. 

ArtiLink 500’s OBD database has many of the manufacturer specific codes that widens its scope compared to those that only use only generic codes. After I introduced a problem with my 2014 Audi AllRoad, the scanner showed the fault and zeroed in on the problem. I was able to turn off the check engine light but the scanner stopped short of providing repair advice that the CarScan Pro 5210 does.

At $59, the Topdon ArtiLink 500 provides many of the abilities of a scanner costing much more but is on the big and heavy side.  

Best OBD-II scanners: ThinkDriver Bluetooth OBD-II Scanner

(Image credit: ThinkDriver)

14. ThinkDriver Bluetooth OBD-II Scanner

Easy to plug in or remove, the ThinkDriver Bluetooth OBD-II Scanner puts an emphasis on maintenance

Specifications
Display/size: 1 LED
Bluetooth/handheld: Yes/No
I/M Readiness test: Yes
Displays live data: Yes
Number of keys: N/A
Warranty: 1 year
Size: 2.1 x 1.8 x 0.9 inches
Weight: 1.3 ounces
Reasons to buy
+Soft grips on sides+Maintenance functions+Excellent software
Reasons to avoid
-App cost-Need to activate

Easy to use, the ThinkDriver Bluetooth OBD-II Scanner ironically is a slow starter. It not only requires an account, an email verification and hardware activation but you’ll need to update the app and firmware. The first time you use it, figure on spending 20 minutes before you get any automotive data.

It’s worth the wait because the ThinkDriver app is more thorough than its competitors. Its dark interface shows all the data needed, including fault codes, live car data, a pre-inspection I/M readiness test and a comprehensive Health Report. It’s one of the rare apps that can reset the maintenance light on your car for things like changing the oil or replacing the EGR valve. 

The ThinkDriver Bluetooth OBD-II Scanner’s soft grips make it easy to install and remove and it connected quickly with my iPad Pro and had a 30-foot range; there’s also an Android app. It quickly found my introduced fault and allowed me to turn off the Check Engine light. 

Unlike those that supply free software, the ThinkDriver app expires after a year and costs $15 a year for one car after that. Still, at $70, the ThinkDriver Bluetooth OBD-II Scanner is worth it for those who prefer to change their own oil.

(Image credit: Tom's Guide)

15. EDiag YA-101

Reliable and inexpensive

Specifications
Display/size: Color/1.8 inches
Bluetooth/handheld: No/Yes
I/M Readiness test: Yes
Displays live data: Yes
Number of keys: 4
Warranty: Lifetime
Size: 4.8 x 2.6 x 0.9 inches
Weight: 6.1 ounces
Reasons to buy
+Excellent for the low price+Battery and I/M tests+Lifetime warranty and updates
Reasons to avoid
-Limited interface-Few high-end features

The EDiag YA-101 is small and light, and its inexpensive price belies its wide array of diagnostic functions that include a battery-test sequence and an I/M inspection-readiness test. It has a lifetime warranty that includes endless firmware updates.

What you won't get are the manufacturer-specific codes and routines available on OBD-II scanners that costs many times more than the EDiag YA-101. This scanner has a color screen and a fairly intuitive interface, but it doesn't graph data and can't turn off the oil-change light. Nor can it suggest repairs or replacement parts.

The EDiag YA-101's 32-inch cable isn't enough to reach the engine bay. If you want to get under the hood while the scanner is plugged in, you'll need an extension cable. Nonetheless, this is a great way to get started with using OBD-II devices, and you'll get a lot of bang for the buck with this cheap but reliable scanner.

Read our full EDiag YA-101 review.

Launch CR529 (Image credit: Tom's Guide)

16. Launch CR529 OBD-II Scanner

This OBD-II scanner delivers pro-level features for an affordable price

Specifications
Display/size: Color/2.8 inches
Bluetooth/handheld: No/Yes
I/M Readiness test: Yes
Displays live data: Yes
Number of keys: 8
Warranty: 2 year
Size: 6.5 x 3.8 x 1.2 inches
Weight: 10.5 ounces
Reasons to buy
+Rugged design+2-year warranty+Lifetime updates
Reasons to avoid
-Big and heavy-Slow to respond

With a rugged design, easy-to-use interface and lifetime software updates, Launch’s CR529 comes close to being a professional OBD scanner at a bargain price. On the downside, at 10.5 ounces and 6.5 x 3.8 x 1.2-inches, it’s bigger and heavier than Innova’s CarScan Pro 5210 and can be a lot to hold during repairs.

Solidly built, the CR529’s ribbed case can protect it if dropped. Its 2.8-inch color screen shows everything from engine misfires and oxygen sensor status to live automotive data and fault codes. Anything can be printed via its USB port but the CR529’s explanations of the problems it finds pale compared to the in-depth repair details of Innova’s 5210. 

The scanner’s eight-key format has a dedicated pre-inspection readiness test key, and the scanner’s LEDs light up red for a permanent fault, yellow for an intermittent fault and green for a clean sweep. 

The Launch’s CR529’s 43-inch cable quickly connected to my Audi AllRoad, picked up my added fault and let me turn off the check engine light. Unfortunately, it took upwards of 15 seconds for the scanner to respond at times.  

The CR-529’s 2-year warranty is combined with lifetime software updates. At less than $50, it’s priced like a DIY unit but has the abilities of a professional scanner.

Best OBD-II scanners: Nexpeak OBD2 NX501

Nexpeak OBD2 NX501 (Image credit: Tom's Guide)

17. Nexpeak OBD-II NX501

Built tough with a bright color display

Specifications
Display/size: Color/2.8 inches
Bluetooth/handheld: No/yes
I/M Readiness test: Yes
Displays live data: Yes
Number of keys: 8
Warranty: 3 years
Size: 7.6 x 3.8 x 1.3 inches
Weight: 1.6 pounds
Reasons to buy
+Bright icon-based display+Long cord+Lifetime software updates
Reasons to avoid
-Big and heavy

The Nexpeak NX501 may be big and heavy, but it goes beyond the expected car checks with a long 5-foot OBD cable and lifetime software updates.

With soft rubber bumpers, the NX501 is ruggedly built and comfortable to use. Its three LEDs for the I/M preinspection test show green for no faults, yellow for a temporary problem or red to show a permanent fault. 

In addition to examinations of the battery and oxygen sensor, the NX501 interprets generic and many manufacturer-specific fault codes. The device quickly noticed the introduced fault on my car and turned off the car's check engine light.

At 2.8 inches, the NX501's display is bright with colorful icons for different features, and it can show everything from engine speed to coolant temperature along with colorful fever graphs. The tool's eight-key navigation makes it easy to move between scanning tasks. With its padded case, lifetime software upgrades and one of the longest OBD cables, the NX501 is one of the best OBD2 scanners for the money.

How to choose the best OBD-II scanner for you

If you're looking for insights into how your vehicle is working or what's wrong under the hood, there's no better way than to plug in one of the best OBD-II scanners and read the results. 

After all, it's how your car dealer or repair shop would figure out what's wrong with your car when you drive (or are towed) in. Why shouldn't you have the same information?

The best OBD-II scanners provide the right mix of size, weight and the ability to read your car's fault codes and live data. The most important criteria are:

  • Easy setup. If it takes forever to set up the scanner, you probably won't use it to diagnose a problem early.
  • Faults and explanations. The best OBD-II scanners not only tell you the faults your car has but also can explain the meaning so you can either fix it yourself or tell a mechanic.
  • I/M Readiness check. A good scanner will run the major engine and emissions tests to see if you'll pass your state's inspection.
  • Accuracy. A scanner is worthless if its results aren't accurate, because the only thing worse than no information is incorrect information.
  • Size and weight. If the scanner is heavy and bulky, chances are it'll stay in your toolbox and not in the car to help you on the road.
  • Live data. By tapping into the car's engine speed, timing and other parameters, the right scanner can help track down an intermittent problem.
  • Graphs. Numbers are good, but a visual representation of it is much better, particularly if you're comparing before and after.
  • Warranty. You expect your car to last at least eight or 10 years, so why shouldn't your OBD-II scanner? That said, the best offer a lifetime warranty that should outlast your ride.

There's a gas tank full of criteria used to determine which OBD scanner is the best one for you. The most important is whether you want one that connects with your phone or tablet's screen over Bluetooth or a handheld unit with its own display and cable. 

Next, think about longevity and get one that includes lifetime warranty or software updates so the scanner will stay current with changing automotive tech. 

Then, how about screen size for a handheld scanner? Get the biggest, brightest and easiest display to read that is icon based for easy changes. If you're clumsy, look at rugged scanners with rubber bumpers to absorb the shock of being dropped.

Look for extras that are included on some models, like an electrical multimeter, the ability to read a manufacturer's proprietary codes or export documents as Acrobat PDF files. 

Finally, the price for these sophisticated devices is right on par with professional-level scanners that are available for under $100. That's barely an hour's labor for a qualified mechanic, making it a win-win purchase.

How we test OBD-II scanners

To test the best OBD2 scanners, I used my 2014 Audi A4 Allroad vehicle while it was in the garage or on the road over a period of several weeks. After connecting each scanner to my car's OBD-II port, I made sure they could report the car's vehicle identification number (VIN). 

For the wireless scanners, I connected to my Apple iPad Pro, Microsoft Surface or Samsung Galaxy S9+ phone via a Bluetooth or Wi-Fi connection. The handheld scanners only needed to be plugged into the OBD-II port, which provides power.

Next, I measured the cord's length on the handheld scanners and the wireless range on the others. With the car running, I monitored the engine and other vital systems, and then disconnected the engine's oil temperature sensor. 

Finally, I checked the details provided by the scanner, fixed the problem, turned off the check engine light and erased the error code.

Then I hit the road to see if the scanner could display operating data such as engine speed, timing and coolant temperature. I paid attention to whether the device reported the data as numbers, graphs or auto-style gauges.

Regardless of which OBD-II scanner you use, you'll need to crack its code. All fault codes have four numbers and a letter prefix:

  • Powertrain (P)
  • Body (B)
  • Chassis (C)
  • Undefined (U)

Of the roughly 5,000 diagnostic fault codes available, some are generic and apply to all cars, like air temperature and throttle position. For these, the numeric section starts with a 0. Others are specific to individual carmakers and represent either a special piece of hardware or a more in-depth analysis of the problem. These start with a 1.

For instance, if you get a P0098 code, chances are there's something wrong with the engine's intake air temperature sensor. By contrast, a Ford that displays a P1112 specialty fault code means that the intake air temperature sensor is reporting values intermittently and should be replaced.

Brian Nadel

Brian Nadel is a freelance writer and editor who specializes in technology reporting and reviewing. He works out of the suburban New York City area and has covered topics from nuclear power plants and Wi-Fi routers to cars and tablets. The former editor-in-chief of Mobile Computing and Communications, Nadel is the recipient of the TransPacific Writing Award.

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