Oscilloscope, Scan Tool or Code Reader
Tech study | June 27, 2021
In their everyday professional activity, service specialists are confronted with the question of whether they need a special automotive oscilloscope or the standard scan tools and code readers would be enough. To answer this question, we must first see how each of these tools work and what are their purposes.
In every modern car, the main control and management of all units in the vehicle are carried out by the on-board computer (Engine Control Unit, ECU). It monitors all parameters and performance of the individual components in the system. If some problem occurs, the ECU records information about the current state as a number, called an error code. This is the so-called On-board Diagnostics (OBD). There are different interface standards for the communication between external devices and the on-board computer, and also the exact meaning of individual codes. The most common is the OBD-II standard.
Read more about vehicle oscilloscopes and the diagnostic software we offer.
Code reader
The code reader is an intelligent electronic device. It connects to the on-board computer via a standard port and can obtain the necessary information about errors been recorded in memory. These codes are useful in initially targeting the source of the problem, but they often can be confusing in further diagnostics. Experienced professionals know from their long-standing practice that such mistakes do not always indicate the exact cause of the problem and should be considered only as a very initial stage of the diagnostic process. The point is, the on-board computer manages all real-time engine tasks, system safety, and vehicle performance in general. Therefore, it is not a good idea for the ECU to be overloaded running sophisticated algorithms used to analyze the encountered problems and also requiring large computational resources. It simply monitors the system's basic parameters, and if it detects some deviation, it records the corresponding code. For example, it can monitor the signal level of the various sensors or their supply voltages, and if the values are out of range, it writes an error code. But this code can not say anything about the true cause of the problem. It can be found only after in-depth professional examination using different tools.
Read in more details about all technical specifications of BOSA car scopes.
Scan tool
The scan tool (or car diagnostic scanner) is essentially a code reader but has more capabilities and can perform some additional tasks. For example, it can not only read out the error codes but also delete them in the ECU's memory or change some of the system's on-board parameters. It can also show a real-time engine performance by continuously reading the sensor outputs and displaying data in graphical format, but in many cases, this type of instrument does not provide a detailed picture of the system’s current state.
Error codes provided by on-board auto diagnostics are a really useful tool in monitoring the operation of individual units in the vehicle, but essentially remain a simple numerical abstraction containing too limited information. On the other hand, using an automotive specialized oscilloscope is the only way by which the problems in the engine and the car, in general, can be explored in deep. It shows the exact form of the combustion process in the cylinders, the current in the primary ignition coil, the pressure and compression in each cylinder, the pulsations of the exhaust gases in the exhaust system, changes of the gas pressure in the inlet manifold, the signal shape of each sensor and so on.
Learn about different types of digital interfaces used in modern car scopes.
Sure, the modern car scanners and code readers are indispensable tools used by every automotive service expert. Investing some time and money in them is really worth it. But the professional diagnostics would not be possible without such a powerful and versatile instrument like the automotive oscilloscope.
On the library page you can read more about modern vehicle diagnostics and some of our interesting scientific works. Call us on our contact page if you have more questions.