OBD II. A connector that tells the truth

Modern cars are packed with electronics. This can be considered a disadvantage, since countless sensors and modules are not eternal. But engine diagnostics and control have never been so simple, quick and precise before.

In the second half of the 90s, cars began to receive an OBD II diagnostic connector. In the US it has been required since 1996. In Europe, cars with gasoline engines must have had a 16-pin socket from 2001. In diesels it became a necessity in 2005. Of course, they arrived aboard much earlier. Differentiating electrical harnesses and adapting them at the last minute to new regulations had no economic justification.

The on-board diagnostics system is a very advanced tool. It monitors exhaust gas composition as well as key engine performance parameters. The traces of memory remain, among others after excessive depletion or enrichment of the mixture, or problems with the throttle, flow meter, crankshaft position sensor and “falling out” ignitions. The driver is immediately informed about more serious problems – a yellow “Check Engine” icon appears on the instrument panel.


The great advantage of OBD II is the normalization of the socket and basic error codes. Universal, available for purchase even in a supermarket, the diagnostic device will allow you to read and delete errors related to key sensors and engine operating parameters as well as incorrect composition of exhaust gases.

In order to get to the information stored in ABS controllers, airbags, power steering, gearbox or transmission, it may be necessary to have an interface dedicated to vehicles of a given brand. Universal devices usually do little. They are unable to read specific protocols and codes.

You need to look for OBD II connectors in the car. Most often they are hidden in the lower part of the dashboard or in the fuse box. It happens that they were mounted in the center console – for example, behind an ashtray.

We will buy scanners for reading and deleting basic error codes in every decently stocked automotive shop. Prices? From several dozen zlotys and above. The information contained in the on-board diagnostic system can also be read in other ways. PLN 30-40 allows you to buy a cable terminated with OBD II and USB plugs. If we install the appropriate software on the computer, it will act as a diagnostic device.

Wireless interfaces are also available. Some store a complete set of information in the internal memory, others send data (Bluetooth or WiFi) in real time, which can be received e.g. by telephone with an appropriate application.


Since the sensors monitor almost all engine operating parameters, nothing prevents them from being presented to the driver. A phone with an application (e.g. Torque) transforms into a panel of additional indicators. It can provide information on RPM, speed, boost pressure, coolant temperature, combustion, current power used …

Nay. Applications can also specify acceleration times (e.g. from 0 to 100 km / h) or sprints over a specified distance (e.g. 1/4 mile). An interesting feature is the “virtual” dynamometer. Electronics measures acceleration times and related them, among others to the weight of the vehicle, trying to determine the maximum value of power and torque. Obviously, the obtained values will be less accurate than the results of professional measurements, but they are enough to determine whether the engine has lost an excessive number of horsepower due to defects or wear.

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