All you need to know about vehicle digital diagnosis

The diagnostic test can reveal existing flaws including problems with the exhaust, transmission, oil tank and other systems. Photo by Rachel Mabala

What you need to know:

According to, OBD stands for On-Board Diagnostic, a standardised system that allows external electronics to interface with a car’s computer system. It has become more important as cars have become increasingly computerised, and software has become the key to fixing many problems

“The need to diagnose any mechanical problem with ease caused me to opt for digital diagnosis,” Simon Were, owner of a VW says. He adds that it not only saves him money but time.
Jimmy Etyang, a mechanic at S-Line Motors LTD, says the amount of time spent on locating car problems, the hefty sum spent on the repairs or the sudden case of car malfunctions is very annoying. Etyang explains that the OBD is an automotive term referring to a vehicle’s self-diagnostic and reporting capability.
OBD systems give the vehicle owner or repair technician access to the status of the various vehicle subsystems, an intelligent system where different types of sensors are integrated into the vital areas of the vehicle that monitor the performance and report the system whether those areas are working according to the designed specifications of the vehicle or not.
When any anomalies are found, the sensors trigger an error code that is stored in the responsible controllers to be retrieved by the technician; and those that require immediate attention illuminate on the vehicle’s dashboard.
“There are several diagnostic codes and these are stored in the relevant controllers simply awaiting to be triggered by a fault within the system, which then is reflected on the dashboard panel. However, they are different for various error types while others will not show on the panel unless retrieved with a diagnostics tool,” Samuel Okello, a mechanic specialising in German cars explains. To eliminate the confusion, Okello says mechanics have the car’s OBD II port at their disposal, which when connected to the diagnostics machine, the codes are retrieved and the technical skills of interpretation and repair come into play.
He adds that this software offers several benefits such as:

Early diagnosis of malfunctions
Detecting small issues before they get out of hand may not be easy for any driver. However, delayed diagnosis could make repair so costly. But with this system, the car owner is saved a great deal, not only moneywise, but also regarding time. For example, detecting misfiring before catalysts get damaged helps in taking the proactive decision such as replacement.

Reduce pollution
One of the main reasons that this system was recommended was to create a healthier environment. “Without guess work or delayed diagnosis, cars work at optimal functionality and therefore the amount of emissions produced are less,” Etyang shares. He adds that it is a little wonder that works manufactured lately are more electronic than those manufactured in the past.

Workshop and reputation saved
Previously, mechanics fiddled with cars in the hope of finding a problem only for them to return the car and the issue persists. “However, with this system, problems are diagnosed and their urgency detailed which saves the mechanic’s time and name in the long run,” Okello says. That also helps the mechanic to get more referrals.
The ease of use is second to none. Simply plug the cable that is connected to a computer with the diagnosis software into the adapter, start the engine up, and watch the information screen change with updates, and more. The errors are retrieved and a simple additional research gets you fixing your car in no time.

Finding the root cause of a given fault
Just a little additional delving into error codes and understanding them will help a long way with locating the root cause of a fault. A car that is overheating can be doing so because of a wiring fault of one of the numerous temperature sensors. Only OBD can save you to locate it. With persistent problems, Etyang mentions that some clients may not be willing to pay you. However, with OBD, unnecessary spare parts do not have to be purchased, which saves the mechanic their money.

Longer road life
Given that there will be no guessing where the problem in the car lies, the car will be able to serve its owner for a longer time.However, despite the improvement in car diagnosis, Okello and Etyang point out that the expertise of the user matters a lot for success to be attained.
Otherwise, one will not easily interpret the codes or know where to open to correct an issue.
At S-Line Garage, OBD is at Shs50,000 for smaller cars such as Golf while commercial cars have it at Shs120,00. However, Etyang says it is only charged as a stand-alone service if that is all the client needs.
“Otherwise, it is usually embedded in the labour,” he adds. The same service can also be got at Ranger Motors, Wamuco Motors, among others.