Experience has shown me it’s best to look for clues and ask some questions if needed before testing components. I’ll look for signs of recent accident damage, water leaks, heavy corrosion, or recent works carried out on the vehicle. It has all of the features of the other offerings in this test and displays monitor and I/M readiness status (which provide insight into the car’s emission control systems), O2 sensor info and evap system tests capabilities (mostly concerns US models with a charcoal canister to trap and store fuel vapours). What’s more, the tool gives live vehicle data readings and there’s a “Code Lookup” feature that provides a clear explanation of the diagnostics codes. So if the cheapest wired scanner – the Motorpower – is capable of scooping top honours, can the lowest-priced device in this test also achieve great things? The product is supplied with an in-depth user manual which explains all the diagnostic codes and operation instructions.

Hard codes, on the other hand, are current static faults that are affecting vehicle system performance. These types of codes need to be repaired before they can be cleared from the computer module. It all depends what app or other software you are using to receive the data and display that data in a meaningful way. Also depends what sort of data (which data items of the tens of thousands possible) it is that you want to read.

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Scan tool plug connector fault – I’ve worn out a few of these guys; they work hard and wear out. The tool’s plug spades can become bent or worn, which causes a poor connection or no connection. Wiggling the plug in the OBD port usually lets you know it’s time to change the cable.

The device will work with all OBD II certified vehicles from 2001 onwards (including CAN). Not compatible with motorcycles and hybrid & electric vehicles. Out of the box, Draper’s cheaper OBD reader here has a rather annoying beep on every button press. Fortunately this can be turned off in the system set-up menu. The reader requires no battery, it plugs straight into the vehicle’s connection point for it to power up. It is compatible with all petrol vehicles from 1996 and diesel vehicles from 2004 that are OBD II compliant (including CAN). This test won’t work for all vehicles; it will depend on how the vehicle’s communication system is configured. Some systems may use a gateway module that limits the usefulness of probing the DLC. In such a vehicle, reading at a module harness is more valuable.A technician may describe soft codes as historical anomalies or intermittent codes that don’t affect vehicle function.