INSTANT E XPERT
Saving money and working on a modern car from home is almost impossible without help from digital on-board diagnostics, leading Rob Marshall to investigate from where a novice should start.
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Like all DIY, decent tools are vital first investments. While good quality screwdrivers, socket sets and spanners are as relevant to maintain and repair your car from home as ever, you should also consider your digital needs. This feature will set you along the correct path, by explaining the basics of on-board diagnostics, why it has become necessary, how to marry the correct tools with your requirements, the cost implications, plus the scope and general limitations of home user equipment.
Defining diagnostics
Naturally, fault-finding of any type cannot be limited to a single parameter – and automotive applications are no different. Formal technician training emphasises the importance of being a detective, which tends to start by asking the customer basic questions about the nature of the issue, such as the conditions under which it occurs. By virtue of you dedicating time to read this feature, you are likely to be more perceptive mechanically than the average driver. Use this instinct to help you in your diagnostic process, which you can develop over time.
Be aware also of the many other diagnostic tools that can help you, including those taken for granted. Your body is a good start: being sensitive to
unusual smells, sounds and vibrations will stand you in good stead. Do not forget the plethora of non-electric diagnostic tools either, ranging from engine cylinder compression testers to brake fluid vapour lock assessors and fuel injector leak-back kits. Obviously, these items are not considered within this feature but you may consider purchasing them, should you choose to undertake more complex repairs.
Electronic diagnostics is also a multifaceted topic in its own right. Perhaps the best value purchase you can make is a digital multimeter. They may look daunting but it is worth buying, learning and experimenting with one, especially if it possesses a Direct Current (DC) clamp meter. Other equipment includes those for tyre pressure monitoring repairs and 12-volt battery analysis. You can also invest in mobile ’phone apps that rely on Bluetooth connectivity. An obvious example is LeafSpy, designed for the Nissan LEAF Battery Electric Vehicle. At the other end of the ability scale, more advanced DIYers will find an oscilloscope useful, more about which was covered in our January 2021 issue.
The important consideration, therefore, is to be aware that hand-held diagnostic hardware that plugs into a standardised sixteen-pin socket within
