Guide and everything you need to know to buy an OBD self-diagnosis system for car faults

For several years, all cars have had a diagnostic system that searches for errors and faults in the vehicle’s engines and systems. Now we can get one and do a self-diagnosis, the problem is knowing which one we should buy.

The ODB (On Board Diagnostics) is a system that allows us to detect breakdowns and errors in our car. It is a technology that has evolved over the years and is currently working with OB3 and OBD2.

Its origin comes from when in California, back in 1988, it became mandatory to install it in order to control and reduce polluting emissions.

What this system did was control that the maximum stipulated in terms of contamination was not exceeded and if this happened automatically, it warned.

From 1996 it is mandatory in the United States and in Europe it adapts to ODB2 making it mandatory in gasoline vehicles from 2000, diesel cars from 2003 and trucks from 2005.

All this has evolved to the systems that we have today where we can see errors and breakdowns that the car has.

How does the OBD socket work?

The vast majority of vehicles have the ODB socket on the underside of the steering wheel or on the passenger door. Anyway, in the vehicle user manual It should indicate where it is.

It connects by cable to a diagnostic center which today is usually a tablet, although there are already smartphones that, having the necessary software, can work just as well.

Normally, the connection is made by means of a RG-232 con cable, although lately there have been technological advances in this regard and there are already models with Bluetooth and Wi-Fi.

The operation can be divided into three parts:

• Data collection: car systems such as the engine or other parts are monitored to verify that everything works well and collect data.
• data transfer: all the data collected from the different sensors are passed directly to the diagnostic center. If it is in a workshop or if it is you in a particular way, said data will appear in what you have used as the main device, as if it is the ITV that connects to the ODB.
• Data: the program analyzes the data and determines possible breakdowns or errors, as well as the solutions that can be applied to such problems. In the case of detecting an anomaly, it is identified by means of a 5-digit code.

These digits can be easily interpret, although, as usual, we must have some kind of bible where the numbers of said failures are located. But still the structure is always the same.

A letter always appears first.

This tells us:

• P: engine and transmission.
• B: bodywork
• C: chassis
• U: undefined

The first number will determine to whom the error is directed, that is, if it is standard or internal to the brand.

We have two options:

• 0: code common to all brands
• 1-9: only for the vehicle manufacturer

The second number tells us where the error is, that is, the area where we should look to solve it.

We have up to 7 possibilities:

• 0: electronic system
• 1- 2: air / fuel
• 3: Ignition system
• 4: auxiliary emission control
• 5: speed and idle control
• 6: ECU
• 7: transmission

The last two numbers are related to the specific error, so that’s why we should look at the list of failures that every workshop should have to know which one is exactly talking about.

At the user level, it is difficult to have this dictionary of errors, unless your workshop would like to share something unusual, or your ODB scanner already comes preconfigured with these errors.

What to look for when buying a diagnostic machine for the car

The first thing you should look at is the functions that the scanner is capable of, that is, not only be able to read, but also interpret different types of errors that may come out, in addition to being able to delete data (something that we do not advise you unless you are very expert in this subject), among other things.

Those that tell us that it is the error, even suggesting solutions they are the best, at least in operation.

Another thing we should pay attention to is that it is compatible with the brand of our car and the more manufacturers support the better, it will not be that we change the vehicle and it becomes useless.

The machine interface It is also something to take into account, since, if it is not easy to understand or the quality of the visualization is poor, the final result can be in danger, since we can interpret that it indicates one code and it turns out that it is another.

Another thing that seems essential to us is the fact that the updates that the scanner receives are regular and every so often. This will make it always up to date, so its interpretation should always be totally correct. Something very positive is that the vast majority come with lifetime updates.

Most are connected by cable, but we can also opt for other technologies such as Bluetooth and WiFi, although the latter requires a permanent Internet connection.

ODB you can buy on Amazon

Now that we know what we should look at and on top of that we have discovered how ODB systems work, you should know that there are some very interesting ones that we can buy on Amazon.

We are going to select a few for you and so you do not have to start looking for them:

Now that you know different models to buy and that you have all the necessary information to know which one you need, you will be able to buy without any fear of making a mistake.

You can tell us which one you have acquired and why on our social networks, so that we can know your opinion.