This device is designed to connect the interface of the car with the computer interface and convert the streaming signals that go along the K- and L-lines. You can purchase this device at any auto parts store for a fairly reasonable price. In the event that it is possible to do it yourself, first of all you need to purchase components and have a reliable information base.
The operation of an electronic device significantly reduces the risk of possible damage to car systems and promptly informs the driver about this. In this article, we will talk about using the K-Line adapter, as well as how to make one yourself.
The K-L-Line adapter is used for diagnostic work and determining the operating parameters of engines on foreign-made cars, as well as domestic cars that are equipped with electronic control units for engine systems.
After connecting the adapter and running the appropriate program on the computer, you can perform the following diagnostic operations:
It is also possible to control and monitor systems while driving:
Diagnostics with a K-line adapter is possible only if there is special software that will correspond to the brand of the car.
Diagnostic measures on domestic cars of the GAZ and VAZ brands are often carried out using the Open Diag program (1.3.9). It is the latest version, perfectly suitable for VAZ, UAZ, GAZ car models.
Also, for the diagnosis of VAZ models, the Motor-Tester and Diagnostic Tool v 1.3.1 programs are used.
Engines equipped with an electronic fuel injection control system with IKAS-5.4 control and their modifications, as a rule, GAZ and UAZ, are diagnosed by an adapter using the GAZ-DIAGN software.
Checking imported cars is carried out using various diagnostic programs that correspond to this manufacturer. As a rule, they are rarely interchangeable due to the design features of engine systems. So, for Chevrolet cars, the "Chevrolet Explorer" v 1.6 software is perfect. With this adapter, you can read information about the status and operation of engine, automatic transmission, chassis systems. This software has various modifications and the ability to work on many Chevrolet models.
Daewoo manufacturer's cars are diagnosed using the Research Daewoo program and its modifications.
There are many different programs for computer diagnostics of vehicle systems. In turn, these contribute to the correct conduct of diagnostic operations. Also an important aspect is the vehicle on which they are used. It is on these basic parameters that the programs differ from each other.
Motor-Tester software, VAG-Tool, Com K-Line VAG adapter and Uniscan have different characteristics, unique interface and are designed to work with certain car brands.
Vehicles manufactured by VAG (Volkswagen, Seat, Audi, Skoda including) with an electronic fuel injection system work with the VAG Com program. The K-line adapter reads and processes the information of all engine components, which allows you to prevent and eliminate various problems in a timely manner.
The "Motor-Tester" diagnostic tool is widely used for diagnostic operations of domestic transport systems.
It is not whimsical and can be used in almost various conditions. Through the software, it takes indicators from the electronic control unit. At the same time, it is possible to save the indicators that the tool visualizes both in digital terms and in graphical form.
Uniscan is a program that has proven to be more versatile. The use of this is possible on vehicles manufactured in the United States, Asia and Europe with a year of manufacture up to 2001 inclusive. By downloading this program to a computer, you can easily carry out diagnostic operations of machine systems and determine with high accuracy the cause of a malfunction of a particular part.
This tool can also be made by hand. The circuit on Com is simpler, but due to the lack of this connector on laptops, it is less practical, and therefore unpopular.
As for schemes with the ability to connect via USB, the situation is different here. They are more practical, but have a complex design. To facilitate this task, the craftsmen began to use a data cable from unusable mobile phones.
For work, we need the following tools and materials:
The process of assembling a circuit can be carried out in three ways: using a breadboard, with the manufacture of a printed circuit board, and by surface mounting. In this review, we will talk about how to make a K-Line adapter with your own hands for surface mounting, according to a schematic image, using a cable from a mobile phone. In a radio parts store or in an old computer unit, you can find transistors VT1 and VT2, as well as other radio components.
We use the VD1 diode, it is important that it has a low voltage drop. To protect against interference, it is important to install capacitor C1 on the adapter.
After the circuit is assembled, you should move on to the data cable.
First, we load the PL2303 K-Line adapter driver with the ability to support non-standard speed. After the driver is installed, you need to connect the cable and make sure it is working. In this case, it will appear in the device manager on the computer display. Next, you need to remember under what value it is tied. To test the port, install the B&B Com Test program.
The next operation concerns the conversion and connection of the data cable. To do this, you need to disassemble the plug from the side of the phone and unsolder it. We determine the functionality of the wires. To do this, connect the cable to the computer and run the program. Next, select the appropriate one. As a rule, the black wire of the cable corresponds to a negative value and should be heard on the body of the USB plug. Then, using a voltmeter, you need to find a wire whose value will correspond to 3.3 volts. When measuring the voltage on it, you need to write something in the corresponding program window. If the voltage readings change, this means that the cord matches the TxD pin.
Then we connect it to the remaining two, and when connected to the correct wire in the program window, the previously entered information will be copied. This is the output of RxD. After the values are set, they should be soldered according to the scheme.
Before turning on the K-Line adapter, it is important to make sure that the device is installed correctly and that there are no short circuits in the circuit and wires.
You can check the operation of the device as follows.
We connect the adapter to the computer port (having previously powered it with 12 W) and use the same program to check. If the information entered in the upper window is duplicated, then the device is working and it can be connected to the vehicle's electronic control unit.
The K-line adapter is used not only as a method for additional diagnostics of machine systems, but also for flashing the power unit control unit. On certain brands, the firmware is made through the diagnostic plug, while on others it is necessary to dismantle the engine control unit itself and upgrade it. The original version of Gionix is supplied as a standard firmware program, which has proven itself well on Euro-4 generation Lanos cars.
So, we found out what the K-line adapter is for, and how to make it yourself. As you can see, this is a very useful device for every motorist.
About one day I had a desire to do a chip tuning to my top ten. But at that time I didn’t know how to do it, and I didn’t want to contact anyone who does this, because I was used to doing everything myself. I spent a couple of days studying the topic of chip tuning and methods for its implementation. Required for firmware k-line adapter, you can buy it on the site, or you can make it yourself. Buying an adapter is long and uninteresting, so I decided to do it myself.
The first and most interesting, at least for me, was PCB manufacturing .
In order to make the board, I needed: a piece of board 5/5 cm., a laser printer, an iron, blue vitriol, salt and water. I found an unnecessary rear light board from a VAZ 2104 from a friend in the garage, cut off a piece of the right size from it and removed the varnish from the surface of the board with fine sandpaper and water. It’s better, of course, to buy in a radio store, a sheet of getinaks or fiberglass for a printed circuit board, but I didn’t have free time to go. Using the Nero PhotoSnapViewer program, I printed out the adapter diagram in its original size. Before printing, you need to set the printer to the maximum consumption of toner.
Then he transferred the pattern to the board in the following way, lowered the sheet of paper with the pattern into water for a couple of seconds, leaned the pattern against the copper side of the board, dried the sheet on the board with an iron (thus the toner melts and sticks to the board), lowered it for 10-20 minutes water, removed the water-soaked paper with a finger.
For board etching used the most accessible method. For 250 ml. water heated to 80 degrees, two tablespoons of table salt and one tablespoon of copper sulfate crushed in a mortar. For best efficiency, you can let the solution sit for a couple of days, this will speed up the pickling time by a couple of hours. I poisoned the board in an ordinary plate, periodically stirring the solution and looked at the board. The etching process lasted about 5 hours, the main thing was not to miss it, if you overdo it for 10-20 minutes, there may not be a trace from the tracks. When the board was ready, I washed it under the tap and dried it. You need to drill holes for the parts on the board, but it’s not so easy to do this, you need a very small drill in diameter, which I didn’t have and there was nowhere to take it, however, I quickly found a way, not really as effective as drill, but the holes turned out. I took a needle from a sewing machine and sharpened the tip of the needle under a triangle, inserted the needle into a drill, 10 minutes and you're done.
Payment of the future k line adapter is ready, you can buy items, but there was still no time to go to the store, a friend helped me out. The soldering of the adapter took a maximum of 20 minutes. For everything about everything, the budget is about 300 rubles.
Adapter diagram on two chips, max232 And ms33199 .
The location of the elements on the board, the blue arrow indicates the location of the element from the side of the tracks, and the red arrow indicates the opposite side.
Before, there were no skills in etching, soldering, arrangement of elements, I understood everything myself. I used a case for the adapter case, under the car radio panel. To connect to a computer and a diagnostic connector, I used COM port cords (they are also RS232 ).
The adapter worked the first time without any problems. Only the electronic engine control unit (ECU) failed, it turned out that I had January 4.1 with ROM memory, which requires a special programmer 27ХХХХ series ROM(permanent storage device). Of course, I didn’t give up right away, I bought an electro-erasable Winbond 27c512 ROMs from other manufacturers, disposable or erased with an ultraviolet lamp. I unsuccessfully tried to upload a new firmware to the microcircuit using a network card, video card, motherboard, by updating the BIOS. 27ХХХХ series of ROM is flashed only by the programmer, verified !!! All the same, I tried not in vain, now I diagnose periodically. With the advent of the laptop, it became possible to diagnose a car in dynamics. Since modern laptops do not have a COM port, I purchased a COMport-USB adapter for 250 rubles.
IMPORTANT!!! Power for the k-line adapter must be taken from the on-board network.
Adapter COM port USB
Homemade K-line cord - car diagnostic connector.
Cigarette Lighter Adapter Power Cord, borrowed from a car TV.
Connecting a car to a laptop.
Car diagnostics.
Adapter diagram, PCB drawing, parts list, user manual
The K-Line USB adapter cable allows you to connect a PC, laptop and tablet to most cars with a standard OBDII diagnostic connector. Designed to diagnose the operation and reset errors of various auto systems.
It differs from many similar cables in the use of an FTDI converter chip (operating with a non-standard baud rate of 10400) and the presence of a switch that allows you to connect to various OBDII pins to expand the adapter's applicability on different cars. A useful feature of such an adapter is the ability to diagnose not only the ECU (ECU), but also many SRS (AirBag), some ABS, BCM, etc. - the main thing is that they have K-Line and the appropriate program is at hand.
This seller has run out of these cables, but you can easily find them, for example here 
The case is made of translucent blue plastic, quite durable.
The USB cable is quite long - 1.5m.
The red indicator lights up when connected to the on-board network and winks slightly when information is exchanged.
Nothing of value was found on the disk - there are drivers for 2004, VAG COM 2004 and FiatECUScan16.
There are a lot of programs that work with this cable, for example: CASCADE, Vasya Diagnostic, ScanMaster, OpenDiagPro, OBD Scan Tech, TECU, Diagnostic Tool, EasyOBDII, Digimoto, Chip tuning, PCMSCAN, KWP_D, Tiggo Diag, etc.
The cable is not compatible with the 24V electrical system.
Of course, it was not without disassembly 
The adapter is well made.
Real cable diagram. 
U1 - USB to COM TTL converter (FT232RL)
U2 - comparator for level conversion (LM393)
The Chinese have managed to screw up here as usual.
1. Incorrectly designated connection contacts in the right position of the switch. Instead of 12/13, 11/12 are actually connected 
Corrected 
2. Incorrectly organized threshold for switching input comparators. Instead of ISO 9141 and ISO 14230 specifications for K and L lines - 70% of on-board power (about 8.5V) fixed it at 65% of USB power (3.1V). Those. actually used levels for GM's ancient ALDL protocol. This is probably done to increase compatibility with older GM ECUs at the expense of stability, although in most cases, such a scheme will work fine. It would be more correct to add a 5/12B switch. To fix the jamb, I dropped out the SMD resistor R9 and soldered the usual 2kOhm resistor as follows: 
In some cases, the device will work normally without alteration, and if not, a soldering iron in hand ...
3. There is no level switching hysteresis. Under severe interference conditions on long lines, the device may become unstable. I didn’t fix it - it works like that, too. line is short.
4. Lines K and L are absolutely identical, i.e. if the K line is interchanged with the L line, nothing will change. Here the Chinese have overdone something, because the L-Line always works only for the transfer of information, moreover, from the RTS line. We can assume that in this adapter, instead of the L-Line, another K-Line was installed according to the logic OR, hard-wired to 15pin OBDII
Modern L-Line cars are no longer used, so they didn’t remake them.
It was not possible to install the non-original FTDI FT232RL chip - the adapter works with both old and new original drivers under WinXP x86 and Win8.1 x86
Just in case - old drivers
New drivers are installed automatically
After installing the drivers in the properties, we reduce the waiting time from 16ms to 10ms, after which you need to restart the PC. After that, the adapter works more stably.
Conclusion: a useful device for amateur car diagnostics.
I plan to buy +51 Add to favorites Liked the review +27 +71At the request of some readers, I decided to post the simplest one, probably K-line adapter via a COM port (in this case, USB is not an option). It's excellent and proven adapter, its dignity; cheap, unpretentious and can be well poked around in the brains of your car. In this case, only the K-line is taken, we do not need the L-line.
The adapter itself is assembled on only two transistors, here is the diagram - you won’t find it easier ...
First I made a test version of the K-line adapter
So to speak, I started with experiments on a breadboard, I assembled everything haphazardly, the main thing was to hold on and the details fit, there weren’t some details, for example, instead of a capacitor of o.47 microfarads, I put 220 nF, but in parallel ... well, and so on.
I took the variable at 500 ohms, that's what a miracle board turned out at first 
Well, you need to check the performance of this device ...
How to check the adapter without connecting to a car?
So first download the softinka Check It 3.0
We connect our adapter to the computer and apply 12 volts to it. We do it in this sequence, otherwise you can burn the Com-port. We do not connect the K-line itself, since we did not connect to the car.
DOS interface, press any button, press). Then - "skip". Again we press any button and lo and behold)
We get to the menu, where by typing (trial and error - intuitively) we find test \ serial ports \ com1
Then Press Enter
There will be a port test, unless of course you have assembled everything correctly. First, the test will go at a speed of 300 bits per second, then 1200, 4800, 9600, in short, all speeds will be sorted out.
here is an example of a test at a speed of 300 (bps)
If the test passed at speeds of 300 and 1200 bits (baud), this is quite enough for us to make our adapter work normally.
If the test fails, a window like this will pop up...
This indicates that the adapter is not assembled correctly or there is no power on the adapter. Well, the test is over, (it was so, one might say informative) now let's move on to the working version of the adapter.
Working version of K-line adapter
All we need...
Parts list:
First we draw a signet in Sprint ...
2. We print several pictures on a glossy printer to choose a good one. All options were normal - we make three seals.
If there are any jambs, we correct it with a marker. before pickling.
Each car owner at some point is faced with the problem of diagnosing his iron horse, which suddenly stops starting and working normally. To solve this problem, most people use the services of car services, in which a specialist with a miracle device can easily decipher the fault code of your car and help make a qualified repair.
What should a car owner do on the panel of a car whose “Check Engine” lamp lights up, but who does not have the time or money to pay a car service every time for diagnosing his car. There is a solution, of course, manufacturingk linedo-it-yourself adapters.
If you are the owner of a budget foreign car like Daewoo or Chevrolet, as well as any domestic car, except for the latest models of 13-14 years old with a CAN bus, then to diagnose your car, you will be quite satisfied with the usual k line diagnostic adapter, which you can assemble with your own hands.
Currently, on the Internet you can find a huge number of schemes for self-assembling k line adapters made to work via a COM port. Since this connector is currently not available on modern computers, the schemes for assembling k line adapters without virtual COM port converters will not be considered in this article. If your PC has a COM port, you can download diagramsk line adapter for COM port.
Let's take a look at the build process do-it-yourself k line adapter for PC with USBports.
This scheme was assembled and finalized by the Veteran Scooter user.
For assembly we need:
Capacitors:
1) 100nF - these are SMD 1206 non-electrolytes (there are 3 of them)
2) 4.7uF. x 10V - tantalum chip capacitor, powered by USB (you can use a higher voltage value, use a lower value is unacceptable)
3) 10uF. x 16V - tantalum chip capacitor, powered by +12V (you can use a higher voltage value, use a lower value is unacceptable)
As electrolytes, you can use any from 4.7 microfarads to 100 microfarads. Their task in this circuit is to filter interference. Please note that in terms of voltage they are not less than 10V and 16V, respectively.
Resistors size 0805:
1) 27 ohm (2 pcs)
2) 270 ohm (2pcs)
3) 510 ohm (2pcs)
Microcircuits:
Adapter diagram
Both adapters are factory assembled and come with a one year warranty.
