Car computer diagnostics

With the advent of injection and electronically controlled diesel engines, it became possible to diagnose the control unit by reading errors from a computer. A constant increase in the number of various control units (engine, transmission, suspension, comfort), demand for computer diagnostics is born, which in a few minutes will indicate possible malfunctions.

Car computer diagnostics: what is it

Computer diagnostics is a process that includes connecting a scanner equipped with a special program that determines the state of electronic systems, the presence of errors and a lot of other information that indicates the characteristics of the car in real time.

The control units began to appear long before the injector, for example, many carburetors and fuel systems like “Jetronic” were equipped with the simplest ECUs, in which the fuel card tables with specific proportions of the air-fuel mixture were laid. This greatly facilitated the life of the driver, since he no longer had to constantly adjust the carburetor, as well as select the jets, in addition, electrodiagnostics of the fuel system became available.

Then a single-injector appeared, which was equipped with a full-fledged control unit, but its design was so simple that the ECU gave a minimum of information about the state of the internal combustion engine and fuel system due to the absence of a mass air flow sensor, an oxygen sensor, and the use of a distributor instead of an ignition module. 

The end result, which is still being improved to this day, is the injector. The fuel injection system allowed not only to flexibly change the parameters of the fuel-air mixture, relative to the engine operating modes. Now the engine ECU, before starting the engine, independently conducts self-diagnosis and, when started, on the on-board computer screen or the “Check” indicator indicates the detected errors or malfunctions. More advanced control units can remove errors on their own, but they remain in memory, which makes it possible to more widely study the condition of the engine and the fact of quality of service.

Among other things, computer diagnostics are performed on all devices controlled by the ECU (climate control, electric power steering, active suspension, automatic transmission or preselective gearbox, multimedia, comfort control system and so on.

What does it do?

Computer diagnostics allows you to accurately determine the malfunction of the electronics or other vehicle systems, so we get:

• a clear picture of the technical condition of individual components and systems;
• a rough plan for troubleshooting, starting from resetting errors;
• real-time monitoring of engine operation;
• the ability to change some parameters in real time.

What does computer diagnostics of a car include?

First of all, electronic diagnostics begins with an examination for external damage, or by the sound of rotating parts. Next, a scanner is included in the operation, which must be connected to the diagnostic connector located in the cabin under a torpedo or under the hood. Diagnostics includes the following steps:

• reading error codes;
• analog check;
• analysis of the information received, resetting errors and re-reading if errors reappear.

Equipment for computer diagnostics

There are three types of specialized equipment:

dealer - is a scanner that is designed exclusively for one brand of car, it is equipped with service stations of all official dealers. Such equipment allows not only to make correct diagnostics, but also to see possible interventions in control units, exact mileage, error history. The equipment is high-precision, which means that diagnostics is carried out quickly and accurately to determine the malfunction, correct the operation of electronic systems;

• The Universal Scanner is a portable device that is compact and easy to use. The device shows errors, it is possible to remove them, however, the functionality is not so wide, but an acceptable cost allows every car owner to have such a scanner;
• multi-brand scanner - can be of two types: in the form of a laptop computer, or a unit with a tablet. It is usually used at various service stations, due to its wide functionality it performs 90% of the necessary operations. Depending on the brand and cost, it is possible to adjust the operation of control units.

Remember that for personal use, cheap Bluetooth scanners that pair with your smartphone rarely show the correct information about the technical condition of the car, it is better to install an on-board computer that in real time will monitor almost all the processes of the car.

Types of computer diagnostics

Types of computer diagnostics differ in units and assemblies, namely:

• engine - unstable operation, excessive fuel consumption, power drop, starting is impossible;
• transmission (automatic transmission, manual transmission) - delay in gear shifting, jerks when shifting gears, one of the gears does not turn on;
• chassis - uneven wear of rubber, suspension knock, suspension skew (pneumatic), inadequate behavior of the ABS unit.

Methods of computer diagnostics

There are several ways in which you can do electronic diagnostics:

• specialized service station - there is the necessary and certified equipment that will give accurate data on the condition of the car. As a rule, specialists in electronic diagnostics are highly qualified. The cost of checking the machine is appropriate;
• on-site diagnostics is an indispensable service for those who are “stuck” far from the nearest service station. Specialists come to you with the necessary equipment, which will accurately determine the malfunction. It is extremely important to order such diagnostics in large service centers;
• self-diagnosis - allows you to determine the malfunction yourself thanks to the use of an OBD-ll scanner. Depending on the cost of the scanner, its functionality is determined, if you need more than just reading and deleting errors, such equipment will cost from $200.

Diagnostic steps

First Stage - reading errors. Connecting to the diagnostic connector, the specialist reads fault errors from digital media. This allows you to determine the location of the malfunction, where more attention is needed, for example, if the computer showed misfires, you should carefully inspect the candles, BB wires, coils, fuel injectors, in extreme cases, perform a compression test.

Step two – analog test. At this stage, an additional check of the electrical circuit, wiring and connectors is carried out, in the event of an open or short circuit, the ECU may show incorrect information about the current state of affairs.

Stage three – analysis of the received information and troubleshooting. In fact, it is possible to directly deal with the place of failure, after which another connection to the computer is required, where errors are reset and a test drive is performed.

When to go through the diagnosis

Reasons for computer diagnostics:

1. The inadequate behavior of the car or its individual systems is clearly felt, or some unit refuses to work (the engine does not start, automatic transmission gears do not switch, the ABS unit redistributes the efforts).
2. The purchase of a used car. Here you can find out the real mileage, error history, and generally compare the real condition of the car and its history with what the seller says.
3. You are going on a long trip. In this case, you need a comprehensive diagnosis, including computer. Thanks to this, it is possible to carry out preventive repairs, as well as bring along the necessary parts that are suspected of an early failure.
4. Prevention It is useful to carry out diagnostics for each MOT, which will save money in the future, as well as save a ton of time by eliminating sudden malfunctions.

Questions and answers:

What are the features of computer diagnostics of a car? It allows you to check the software of the vehicle control unit (or ECU of all systems) for errors, their decoding, reset and elimination of electronics malfunction.

What is included in computer diagnostics? Search for errors, reset them. An accurate assessment of the health of the on-board system and electronic systems of the car is carried out. Based on the results, it is determined what work needs to be done.