Automotive Computerized Diagnostics is
One major problem faced by automobile technicians and users as regards automobile repairs and maintenances is correct diagnosis of faults and errors. This has caused many drawbacks in the automobile technology industry as many technicians and users end up being frustrated. This could lead to abandoning of the vehicle or selling it off as scrap.
Due to this development various automobile manufacturers thought of creating a system in the vehicle that would aid self-diagnosis and prompt warning lights and alarms in the case of detection of a failing/failed component or system in the vehicle. This self-diagnostic system had to be computerized and needs various sensors and control units to send signals and interpret them.
This lead to the Evolution of the On-Board Diagnostics (OBD) system/protocol, this was integrated in to vehicles and provided a port in the vehicle where the process can be carried. Click here for our Free Courses
OBD stands for On-board Diagnostic, this is a software develop in car to help aid diagnostics, and reduce guesses (trial and error) in car repairs.
The computer inbuilt in the car sends message which can only be interpreted by some specific devices.
Firstly OBDI was first developed, it works by using the voltmeter to measure signal from the ECU (Electronic Control Unit) and the code display signifies a certain fault. This code is called a fault code.
When engines are built each component of the engine has installed a sensor within it, this sensors send electrical signals to the OBD system which helps to interpret this signal into various codes, which are the fault codes we know.
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Older cars used OBD I software, and this feature was first installed for the Engine and Gearbox. But with the advent of OBDII Protocol, we can not only diagnose fault codes from engine and Gearbox, but from all parts of the vehicle including wheels, lights, doors e.t.c. and the later the car the better it’s features.
In order to interpret the messages in OBDII Protocol you need either a Diagnostic Scanner or a Code Reader.
The On-Board Diagnostics (OBD I) system/protocol.
The OBD I Protocol works on a computerized system, in which sensors are placed in various components and system of the vehicle such as crankshaft, catalyst converter, engine block etc. the sensors send signals to an inbuilt computer known as the ECU (Electronic Control Units) or ECM (Electronic Controlled Module) or Brainbox. The ECU (brainbox) then interprets this signal (usually voltage) and send this information to the dashboard or other system where the warning lights and alarms are located, and then to the Diagnostic Port where various interpretation of the various faults detected in the vehicle can be accessed.
Although the OBD I technology has been neglected, several vehicles old vehicles that still operate on this technology are still in used till date especially in Africa and other developing countries of the world.
How to diagnostics using OBD I protocol works.
OBD I protocol works using the Multimeter to read fault codes from the diagnostic port. This code are read as voltage values, each values signifies a particular fault, in order to know the values and their implications we need to have the codes and their interpretations which is usually manufacturer specified, there are usually reference materials that has defines these codes and their interpretation.
Also different vehicles have different method of testing and proper knowledge of the testing operation is necessary before engaging in test operation. Some old vehicles had OBD I & II protocol incorporated which aid one to also test for OBD I protocol using OBD II port.
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On-Board Diagnostic (OBD II) System/Protocol
OBDII protocol is a software technology inbuilt in cars from 1996 till date that helps in diagnostics and programming of such cars. Just as OBD I, sensors are incorporated into almost all components and systems in the vehicle depending on the model or brand. When these sensors discovers any alteration in its proper value range, its send signals (messages) to an inbuilt computer known as the ECU (Electronic Control Units) or ECM (Electronic Controlled Module) or Brainbox. The ECU (brainbox) then interprets this signal (usually voltage) and send this information to the dashboard or other system where the warning lights and alarms are located, and then to the Diagnostic Port where various interpretation of the various faults detected in the vehicle can be accessed. The messages from the computer inbuilt in the car can only be interpreted or reprogrammed using a diagnostic scanner or a code reader.
(for more information on how to diagnose using OBD I protocol contact the author). Contact Us.
The interpretation of this message is from the scanner may be difficult for a novice in automobile diagnostic technology, but modern scanner are designed for easy comprehension, software have been designed to help displayed this messages in computers and smartphones.
