A bidirectional scan tool is a device that you use to send commands to a control module and receive feedback.
But what is the right bidirectional scan tool for yourself?
In this post, I’m going to help you choose the best bidirectional scan tool.
- 1 10 Best Bidirectional Scan Tools Review
- 1.1 1LAUNCH CRP429 Bidirectional OBD II Scanner with Full System Functions
- 1.2 2LAUNCH X431 V (X431 Pro) OBD2 Bidirectional Diagnostic Scanner
- 1.3 3LAUNCH X431 V+ Diagnostic Bidirectional OBD2 Scanner
- 1.4 4Autel MaxiDAS DS808 OBD2 Bi directional Scan Tool
- 1.5 5Autel MaxiSys MS906 Automotive Diagnostic OBD2 Bi-directional Scan Tool
- 1.6 6Autel Maxisys Pro MS908P Automotive Diagnostic Bidirectional Scan Tool With J2534 Reprogramming
- 1.7 7Autel AL519 AutoLink Enhanced OBD2 Affordable Bidirectional Scan Tool
- 1.8 8Autel AL619 Autolink OBDII Affordable Bidirectional Code Reader
- 1.9 9FOXWELL NT630 Elite OBD2 Affordable Bidirectional Diagnostic Tool
- 1.10 10FOXWELL NT510 Automotive Affordable Bidirectional OBD2 Scanner for BMW
- 2 Best Bidirectional Scan Tools: Editor’s Top 3 Picks Comparison Chart
- 3 FAQs
- 3.1 What is Bidirectional Control?
- 3.2 What is a Bidirectional Scan Tool?
- 3.3 What are the various bidirectional diagnostic functions?
- 3.4 Can I get a car to perform an action by itself?
- 3.5 Do I need a high-end scanner to perform bidirectional functions?
- 3.6 Which bidirectional functions can I do myself?
- 3.7 Which is the best bidirectional scan tool for me?
10 Best Bidirectional Scan Tools Review
1LAUNCH CRP429 Bidirectional OBD II Scanner with Full System Functions
Why Buying LAUNCH CRP429?
The CRP429 from Launch Tech is debatably the best bidirectional scan tool so far on this list. Why do I say that? Because it’s the first that supports all three bidirectional functions.
It can perform actuation tests in the ABS. Such tests include ABS motor test, ABS manual control test, ABS version test, ABS auto-bleed test, and the gear tension relief test.
In addition to ABS actuation tests, the CRP429 also supports injector coding. This process involves feeding the ECU with a calibration code so that it can do proper and accurate injection control. It’s mainly done on diesel-powered vehicles.
The final bidirectional function that you will get is reprogramming. In this case, the CRP429 offers two types: key reprogramming and battery reprogramming.
Popularly known as IMMO, key reprogramming refers to clearing the information of a lost key from the ECU and feeding a new key with new information. By doing so the ECU and new will be able to communicate.
Battery reprogramming, on its part, simply referrers to registering a new battery after replacement. This is a common procedure that’s used to make the new battery and ECU compatible.
To summarize that, this bidirectional scanner offers actuation tests for the ABS, coding for the injector system and reprogramming for a new key and/or battery.
The scanner is OBD2-compatible. It works on US-made vehicles that are 1996 or newer models and 2000 or newer models of EU-made cars. While it supports some Asian-made brands, you may experience compatibility issues when trying to connect the scanner and car’s ECU.
- Supports the most important bidirectional functions
- Powered by an AS quad-core processor for fast operation
- Can connect wirelessly using Wi-Fi
- Can diagnose other systems, including engine, ABS, SRS, SAS, and transmission
- Supports various service functions like EPB reset, CEL reset, SAS calibration, DPF regeneration and oil service reset
- Software updates are only free for 12 months
- A bit hard to navigate its menus
Who Should Buy Launch CRP429?
You will find the LAUNCH CRP429 easier to handle once you get the hang of its menus. With plenty of basic and advanced diagnostic functions, it’s the best bidirectional scan tool for DIYers and enthusiasts.
2LAUNCH X431 V (X431 Pro) OBD2 Bidirectional Diagnostic Scanner
Why Buying LAUNCH X431 V (X431 Pro)?
If you like your devices sleek then the LAUNCH X431 V is the best bidirectional scan tool for you. Featuring an 8-inch screen, this device runs on Android 7.1, the same software used in smartphones and tablets.
More importantly, it supports tons of bidirectional tests, starting from component activation to actuation, coding and even reprogramming.
Unlike the CRP429 which only supports actuation tests for the ABS and SRS, the X431 V does so for the ABS, SRS, engine, and transmission. In addition to that, it can do IMMO matching (key reprogramming), SAS relearn, gear learning, new battery registration, electronic throttle position relearn, and injector coding.
With regards to other functions, this bi-directional scan tool supports all 10 OBD2 test modes, can scan all the major systems (engine, ABS, SRS, transmission & SAS), performs oil service reset, TPMS reset, EPB reset, SAS calibration, DPF regeneration, etc.
Built with a 1.4GHz processor, the X431 V works on all OBD2-compliant vehicles. It can connect wirelessly via Wi-Fi. The package includes a dongle for that.
- Nice and attractive design
- Very fast in processing data and reporting results
- Packs plenty of basic and advanced diagnostic functions
- Multilingual menu
- Tablet-like apps for quick access and ease of navigation
- Compatibility issues with Asian-made cars
- Costlier than most other bi-directional scan tools
Who Should Buy Launch X431 V (X431 Pro)?
The high cost of this unit boils down to its wide range of functions. In light of that, it’s perfect for professional users and auto shop owners.
3LAUNCH X431 V+ Diagnostic Bidirectional OBD2 Scanner
Why Buying LAUNCH X431 V+?
It’s hard to go wrong with a Launch scanner, especially if it’s the LAUNCH X431 V+. Featuring a 10-inch screen and Android 5.1 OS, this device could easily rate as the best bidirectional obd2 scan tool.
For starters, it supports bidirectional control of modules. Whether you want to perform an EVAP leak test, roll windows up/down, turn the fuel pump on/off, set the A/C clutch on/off, it can do all that and more.
Secondly, it supports ECU and injector coding. We’ve already looked at these two in details, so no need to discuss them further. Just know that with coding the ECU is able to communicate with a component/module properly.
Finally, you can use the LAUNCH X431 V+ to program new keys, relearn TPMS sensors, do throttle matching and relearn a new battery. All these are reprogramming functions that are crucial to professional mechanics.
Needless to say, this scanner supports a variety of other diagnostic functions. It gives you access to all onboard systems (engine, ABS, SRS, SAS, transmission etc.) and offers multiple reset services. They include EPB reset, SAS calibration, BMS, ABS bleeding, DPF regeneration and TPMS reset among many others.
The scanner is compatible with OBD2-compliant vehicles. It features a built-in Bluetooth module that you can use to connect to the ECU wirelessly. That may prove critical when you need higher mobility as you work.
- Can connect wirelessly using Bluetooth. Comes with a DBScar 5 for that.
- Built with a superfast processor for quick operation
- Auto-VIN saves time by automatically identifying a vehicle
- Compatible with virtually all vehicles sold in the US after 1996
- Nicely built with a colorful and bright screen
- Software updates are only free for 2 years. After that, you have to pay
- After purchase, you have to contact Launch Tech to activate the unit from their end. Otherwise, it will only be capable of reading codes.
Who Should Buy LAUNCH X431 V+?
The LAUNCH X431 V+ is ideal for professionals. If you are an auto mechanic or manage an auto shop then this is the best bidirectional scan tool for you.
4Autel MaxiDAS DS808 OBD2 Bi directional Scan Tool
Why Buying Autel MaxiDAS DS808?
Autel makes some of the best scan tools on the market. It should not come as a surprise that the MaxiDAS DS808 is a fully-fledged bidirectional scanner. Capable of activating monitors, performing actuation tests, coding and reprogramming, this device has everything you may need for successful bidirectional diagnostics.
For starters, it does actuation tests for ABS and SRS. As explained earlier, these tests check whether the mentioned systems operate as they should. If not they will pinpoint faulty components (especially sensors, actuators and relays).
Other tests that you can perform are a leak-down test, power balance test, and all active tests. Together they single out faulty sensors and components in a system. In case you need to know, these tests are in fact bidirectional.
When it comes to coding, the MaxiDAS DS808 does ECU coding. This is where the ECU is ‘taught’ new ways of controlling a module/system. One specific coding that you can do with this scanner is injector coding. In that case, the ECU is reconfigured to do a proper and accurate injection control.
Finally, the MaxiDAS DS808 can reprogram a new key (fob), TPMS sensor, weight sensor. That’s pretty much all the programming you need, especially since you can do ECU relearning (coding) for other systems.
Like any other scanner in its price range, the MaxiDAS DS808 comes with additional functions for basic and advanced diagnostics. It’s a full-system tool that can check the engine, SRS, ABS, transmission, SAS etc.
Besides, you can perform several service functions. They include ABS bleeding, oil reset, EPB service, SAS calibration, and DPF regeneration to name a few. The scanner works on over 80 domestic and foreign car brands.
- Impressively wide vehicle coverage
- Packs several bidirectional functions
- Performs basic as well as advanced (service) diagnostics
- Nice design that resembles a tablet
- Very simple to navigate its menus
- This version is not supported by Autel USA, so in case of any issues you have to reach Autel China
- Comes with a premium price tag
Who Should Buy Autel MaxiDAS DS808?
In all fairness, the premium price tag matches the premium functions of the scanner. That’s why it’s the best bidirectional scan tool for professionals.
5Autel MaxiSys MS906 Automotive Diagnostic OBD2 Bi-directional Scan Tool
Why Buying Autel MaxiSys MS906?
In case you are worried about the fact that the MaxiDAS DS808 (above) is not supported by Autel USA you can opt to buy the Autel MaxiSys MS906. It offers the same exact functions as the MaxiDAS DS808, but with the added advantage of support from Autel USA.
To sum up the functions, you can perform ABS and SRS actuation tests, leak down test, power balance test, and all active tests. It performs ECU coding for the injector as well as crankshaft position. Finally, the MaxiSys MS906 can reprogram new keys, a new TPMS sensor, and a new weight sensor.
As you would expect, the MaxiSys MS906 performs other diagnostic functions too. It can check the engine, SRS, ABS, transmission, SAS and other onboard systems.
Additionally, the scanner can do ABS bleeding, oil reset, EPB service, SAS calibration, DPF regeneration etc. One thing of note is that for this product Autel gives you the option to include the Autel MaxiTPMS TS401 as a bundled product.
The latter gives you tons of functions that are specific to the TPMS (tire pressure monitoring system). It can activate TPMS sensors, show sensor data, reprogram sensors and code the ECU. It’s a deal well worth your consideration, especially if you are a professional mechanic.
- Compatible with over 80 domestic and foreign car brands
- Sleek design with a tablet-like shape
- Diagnostic apps are neatly organized and simple to use
- When you buy this product you get support from Autel USA
- Offers several bidirectional, basic and advanced diagnostic functions
- Most expensive bidirectional scan tool so far on this list
- Doesn’t offer as many programming functions as one would like. E.g. it can’t disable perimeter alarm
Who Should Buy Autel MS906?
Like the MaxiDAS DS808 above, this tool is suitable for professional use. It’s the best bi directional scan tool for mechanics and auto shop owners.
6Autel Maxisys Pro MS908P Automotive Diagnostic Bidirectional Scan Tool With J2534 Reprogramming
Why Buying Autel Maxisys Pro MS908P?
The final bidirectional scanner in our review is the Maxisys Pro MS908P from Autel. This high-end unit costs in excess of $1,800. At that price, you would think there’s nothing it can’t do. You would be absolutely right.
It does everything from sensor activation to advanced ECU coding and everything in-between. By that, I mean active tests, key programming, injector coding, throttle matching, actuation tests, adaptations, matching and everything else that all the other 9 scanners can do.
The one thing that’s important to mention is that this scanner can utilize the J2534 Box to do ECU coding and programming. The only issue here is that you have to buy the box separately. It’s not part of the package.
Is it a worthy purchase?
Absolutely! If you can code or program the ECU you can get any new parts to communicate with the ECU effortlessly.
Alongside bidirectional functions, the Maxisys Pro MS908P offers full-system diagnostics. Meaning you can use it for basic functions like resetting the Check Engine Light and reading/clearing codes.
Additionally, it can perform a variety of service functions like oil service reset, SAS calibration, BMS, EPB function, DPF regeneration, ABS auto-bleeding and many more. In short, it can do most of the things that a scanner can possibly do. That includes coverage for OBD2-compliant vehicles sold in the US since 1996.
- Built with a 1.4GHz quad-core processor for fast operation
- Can connect wirelessly via Bluetooth.
- Compatible with over 80 domestic and foreign car brands
- Has a sleek, tablet-like design
- Offers bidirectional functions as well as basic and advanced diagnostics
- Free software updates are for one year only
- Doesn’t support programming of Benz and BMW vehicles
Who Should Take Autel Maxisys Pro MS908P?
With its price tag and range of functions, you can clearly see that the Autel Maxisys Pro MS908P is a tool for professionals and auto repair shops.
7Autel AL519 AutoLink Enhanced OBD2 Affordable Bidirectional Scan Tool
Why Buying Autel AL519?
Autel AL519 AutoLink is perhaps the most affordable bidirectional scan tool on the market today. Built with a full-color screen this device lets you perform bidirectional actuator tests on monitors.
It features a special ‘Control Mode’ that tests the EVAP, catalyst monitor, O2 sensors and I/M readiness. These are mainly related to emissions, but they are bidirectional tests nonetheless.
Besides that, this Autel bidirectional scan tool configures monitors that you want to test. In other words, it prepares (readies) them for bidirectional tests. So while it might not support many tests, it can act as a great tool for setting monitors.
In addition to bidirectional tests, the Autel AL519 AutoLink offers several other basic diagnostic functions. Top on the list is resetting the Check Engine Light. It also displays vehicle information, freezes frame data and live sensor data.
With regards to vehicle coverage, the scanner is compatible with all OBD2-compliant cars. That includes domestic and foreign (European and Asian) brands.
- Reliable for smog tests (drive cycle verification and Federal/State emission readiness checks)
- Can prepare monitors for bidirectional tests
- Wide vehicle coverage that includes all mainstream OBD2 car brands
- Solid construction with rubber sleeve for extra protection
- Very affordable
- It’s a discontinued Autel scanner, therefore you won’t find newer software updates
- Autel seems to be abandoning customer support for this product
Who Should Buy Autel AL519?
The AL519 AutoLink is arguably the best bidirectional scan tool for ordinary car owners, especially beginners. If you’re on a tight budget you will love just how affordable it is.
Why Buying Autel AL619?
The AL619 Autolink is another Autel bidirectional scan tool. It has plenty to offer despite its low price tag. As far as bidirectional tests go, this unit offers the same exact functions as the Autel AL519 above.
In short, you can use it to perform bidirectional actuator tests on monitors. That includes the EVAP system, catalyst monitor, O2 sensors and I/M readiness tests. Additionally, it configures (prepares) monitors for bidirectional tests.
So, what sets the AL619 Autolink apart from the AL519 AutoLink?
Mode 6! While the former supports viewing of Advanced Mode 6 data, the latter doesn’t. Mode 6 is very important, especially in bidirectional tests that relate to emissions.
It basically indicates whether emission-related monitors are ready for bidirectional tests. If they are (ready) Mode 6 will give a “Complete” or “Ready” feedback.
For example, if you run a test to set I/M monitors “Ready” for a bidirectional test. It is Mode 6 data that will confirm whether they are in fact ready. And if they are ready you can go ahead and perform the I/M readiness test.
The other thing that sets these two devices apart is the number of additional functions. The AL519 AutoLink can pull and clear engine codes only. However, the AL619 Autolink can do the same for the engine, ABS and SRS.
Beyond that, it can display vehicle information, freeze frame data and live sensor data. In terms of coverage, this device is compatible with all OBD2-compliant cars, domestic and foreign. That’s one of the reasons why it can easily rank as the best bidirectional scan tool for car owners.
- Supports viewing of Advanced Mode 6 data
- Wide vehicle coverage
- Very affordable despite the many functions
- Reliable for smog tests (drive cycle verification and Federal/State emission readiness checks)
- Can prepare monitors for bidirectional tests
- Some compatibility problems with certain car brands like Fiat
- Auto-VIN database needs updating to include 2017 and newer car models
Who Should Buy Autel AL619?
Like the AL519, this unit is perhaps the best bidirectional obd2 scan tool for ordinary car owners. If you want to prepare monitors and run emission readiness tests then this is the perfect buy for you.
9FOXWELL NT630 Elite OBD2 Affordable Bidirectional Diagnostic Tool
Why Buying FOXWELL NT630 Elite?
Coming in third is the FOXWELL NT630 Elite. This entry-level bi-directional scan tool allows you to perform active tests mostly for the ABS and SRS. You can activate and control components in any one of those two systems.
The components include sensors, switches, relays, and actuators. That basically means you can perform actuator tests by sending commands to the ABS control module or SRS control module. And the module will respond by imitating an action.
Such a test is important when you’re trying to determine how the two modules respond to commands from the ECU. If the response is not normal, you can figure the problem by performing specific active tests for each component (sensors, switches, relays, and actuators). Doing that will help you pinpoint which component is faulty.
The specific tests that you can perform include ABS motor test, ABS manual control test, ABS version test, ABS auto-bleed test, gear tension relief test, and lamp test just to name a few.
So basically that’s what the FOXWELL NT630 can do in terms of bi-directional tests. Besides that, this scan tool also supports other functions that may come in handy during diagnostics. They include reading and erasing engine, ABS, SRS and SAS codes as well as ABS bleeding.
It works on all mainstream OBD2-compliant vehicles. If your car is a 1996 or newer model then it’s almost certain that you can use this scanner.
- Easily the best bidirectional scan tool for ABS and SRS
- Can diagnose other systems, including engine and SAS
- Has entry-level price
- Comes with free updates for product’s lifetime
- Very powerful for the money
- Noted compatibility issues with some cars like Jeep Wrangler and GMC Savana
- FOXWELL doesn’t offer reliable customer support for this device
Who Should Buy Foxwell NT630 Elite?
Despite the few drawbacks, the NT630 Elite remains to be the best bidirectional scan tool for ordinary car owners who want to do bidirectional tests for ABS and SRS.
10FOXWELL NT510 Automotive Affordable Bidirectional OBD2 Scanner for BMW
Why Buying FOXWELL NT510?
First things first, the NT510 is a brand-specific bidirectional scanner that covers BMW, Mini, and Rolls Royce vehicles. It works on both OBD1 vehicles (made from 1987 to 1995) and OBD2 (from 1996 to date).
For other brands of cars, you can only view and clear trouble codes. So what can you do with an NT510 on a BMW, Mini or Rolls Royce?
You can activate or control onboard systems. That’s a fancy way of saying that the scanner performs actuation tests. Not sure what that means? Read the ‘What is a Bidirectional Scan Tool?’ section (above) for more info on actuation tests.
Some of the components that you can activate/control using the NT510 include switches, relays, actuators, and sensors. Note that it can also activate a full system. For example, if you want the ABS to be active you can do so using this bi-directional scan tool.
In addition to actuation tests, the FOXWELL NT510 can also reprogram new parts. As mentioned already, reprogramming is the process of matching a new component with the ECU. In the case of the NT510, it can reprogram a new battery and TPMS, as well as recalibrate the SAS.
Away from bidirectional functions, the NT510 can check and clear codes in all the major systems. It also performs oil service reset, EPB service, DPF regeneration and so much more.
- A wide range of bidirectional functions
- Covers almost every BMW, Mini and Rolls Royce car
- Quite affordable when you compare price and functionality
- Clear screen with intuitive menus
- Well-built for durability
- Battery registration only works if the new battery is the same type as the old one
- Reported compatibility issues with some BMWs, like the 1999 528i
Who Should Buy Foxwell NT510?
All in all, the FOXWELL NT510 can be termed as the best bidirectional scan tool for BMW, Mini, and Rolls Royce vehicles. It’s perfect for enthusiasts and DIYers on account of its many advanced functions.
Best Bidirectional Scan Tools: Editor’s Top 3 Picks Comparison Chart
LAUNCH CRP429 Bidirectional OBD II Scanner with Full System Functions
LAUNCH X431 V+ Diagnostic Bidirectional OBD2 Scanner
Autel MaxiDAS DS808 OBD2 Bi directional Scan Tool
4.7 / 5
4.3 / 5
4.1 / 5
|Check Engine Light Reset||Yes||Yes||Yes|
|ABS & SRS Scan||Yes||Yes||Yes|
|Bottom Line||With plenty of basic and advanced diagnostic functions, LAUNCH CRP429 is the best bidirectional scan tool for DIYers and enthusiasts.||LAUNCH X431 V+ is ideal for professionals. If you are an auto mechanic or manage an auto shop then this is the best bidirectional scan tool for you.||In all fairness, the premium price tag matches the premium functions of the scanner. That’s why Autel MaxiDAS DS808 is the best bidirectional scan tool for professionals.|
What is Bidirectional Control?
In onboard diagnostics (OBD), bidirectional control refers to sending and receiving information between a scanner and a car’s ECU. The scanner achieves that in two ways.
First, it can request information from the ECU. A good example of that is in case it pulls sensor data from a system like ABS, SRS or transmission. Secondly, it can command a module to perform some tests or functions.
The latter is what we’re more interested in. In that case, you can instruct a module (basically a car system) to do certain things. At times it’s an easier option than having a second person to sit on the driver’s seat and perform an operation.
For example, if you want to know the speed at which the transmission changes gears you can command the transmission module straight from the scanner. From a mechanical point of view, that’s much better than having someone else manually shift the gear.
Bidirectional control is at times known as a functional test, actuator test, system test or inspection test. Regardless of how you want to call it, you need the best bidirectional scan tool to achieve the test.
What is a Bidirectional Scan Tool?
A bidirectional scan tool is a device that you use to send commands to a control module and receive feedback. For example, in the case of the transmission control module, you can use the scan tool to command the module to perform an action. That action can be something as simple as changing the gear.
The module will respond by shifting the gear. In the process, the bidirectional scanner will display helpful information (like shifting speed) that can help you diagnose the system. That is what is known as a bidirectional actuator test.
The second type of function is bidirectional coding or bidirectional adjustment. This refers to changing how a module is currently operating. For example, if the transmission currently has a shift time of 650ms (which is long), a mechanic can use a bi-directional scan tool to recalibrate the hydraulic control and lower the time to, say 550ms.
Essentially the mechanic has changed a component – hydraulic control (and shift time). So the car won’t operate the same way it was before. It will now shift gears faster than it used to.
The third and final type of bidirectional function is reprogramming. Also referred to as J2534 reflashing, this function involves relearning a new component so that it works like the old one.
A good and popular example is TPMS reprogramming. If you buy a new TPMS sensor, you will have to reprogram it.
That not only recalibrates the sensor to match the ECU but it also gives it the same parameters as the old TPMS sensor. The ECU will recognize and work with the new sensor just as well as it worked with the old one.
The best bidirectional scan tool should offer at least one of those three bidirectional functions.
What are the various bidirectional diagnostic functions?
There are three main bidirectional functions, namely actuation tests, coding, and reprogramming. Please check the introduction section for more details on each.
Can I get a car to perform an action by itself?
Yes. With a bidirectional scan tool, you can send commands to on-board systems and get them to perform certain actions like rolling windows up/down without you doing it yourself.
Do I need a high-end scanner to perform bidirectional functions?
No. There are some very affordable bidirectional scan tools. Kindly check the review above for tools that cost under $250.
Which bidirectional functions can I do myself?
You can perform active tests, actuation tests, coding, and reprogramming. That said, please don’t try any of the tests unless you know precisely what you need to do. Otherwise kindly consult a professional mechanic for help.
Which is the best bidirectional scan tool for me?
That depends on your budget and range of functions you need. The review above features 10 of the best bi-directional scan tools. Kindly check to see which one suits your needs.