Code Reader

A Code Reader is an Automotive device used by Technicians to read OBD and EOBD fault Codes, most associated with Cars, Light Commercial Vehicles, HGV Trucks and even some late model Motorcycles. For these applications the term OBD Code Reader or Automotive Code Reader and even EOBD Code Reader are used to describe these handheld devices used by most garages and repair shops anywhere in the World today.

These Code Readers connect to the vehicles Electronic Control Unit (ECU) using a universal 16 Pin OBD (On Board Diagnostic) port or socket, this type of connector has been commonly used from about 2001. Not all 16 pins of the vehicles OBD port have wires connected to them whilst some of them are used for connection to other systems in addition to the vehicles Engine Management System ECU.

Some Code Readers and Deleters are capable of reading and deleting codes in other vehicle systems, these include ABS, SRS, Auto Gearboxes, Central Electronics etc., to name just a few. This type of Code Reader is sometimes called a Scanner or Scan tool, it’s a bit misleading as the name Scanner is normally associated with the tool company Snap On USA.

Code Readers communicate with the vehicles ECU using one of several languages or protocols as they are known and there have been many types over the years. Most recently there has been K-Line, and the most common language in current use is the Can Bus protocol of which there are several types and speeds. Even the most basic and inexpensive types of Code Readers communicate with K-Line and the Can Bus protocols, some even cover the very early KWP 2000 and J1850 PWM system types.

Code Readers vary in price and the different functions they perform and there are many different low costs makes and types available to the general public. Low cost or budget type Code Readers are usually capable of only reading and deleting OBD or EOBD codes and not Manufacturer codes, these require Manufacturer Specific Code Readers or Scan Tools to read and delete these specific codes.

A very important point for the general public to be aware of is that when using an OBD Code Reader and Deleter to delete EOBD fault codes, some Manufacturer codes may also be unintentionally deleted. This is not always the case, but during development of the OBD X BOX it was found that some fault codes, and normally those only visible when using a Manufacturer specific Code Reader, could also sometimes be deleted.

The lesson here to the general public is quite simple and obvious when considering booking your vehicle in for repairs with a professional garage. Do Not Delete Any Codes with your Code Reader When the EML Is on.

Instead, ignore the fact that your EML is on and drive your vehicle for as many miles as you can to give the ECU as much time as possible for it to register any current or pending codes.

Registered fault codes read through OBD will often result in the EML coming on but Pending fault codes generally do not illuminate the EML.

Some Code Readers have a separate menu (sometimes hidden) for these pending fault codes, others do not, as an example the Snap On Scanner displays “DTC’s Detected During Last Drive Cycle” or something very similar. Pending fault codes are often overlooked by most Mechanics and Vehicle Technicians, in actual fact, these pending codes are probably more important than the registered codes that bring on the EML. Pending codes are a means of warning the Technician that the fault(s) hasn’t been fixed and that sooner or later the Engine Management Light is going to come back on, How Can You Afford to Ignore This?

As manufacturers of the OBD X BOX Selective Code Reader and Deleter we’d like to give you just one piece of valuable advice that will probably change your diagnostic approach forever. Make sure you purchase an OBD Code Reader in addition to any Manufacturer level specific Scan Tools you already have that support pending fault codes. If you really want to experience something unique and completely different, consider buying the OBD X BOX and check out it’s Unique DTC Alert Feature.

Rather than trying to explain why you should purchase an OBD X BOX we think it might be more beneficial for you to read a press release we recently had published in The UK Car Mechanics Magazine Feb 2023.

OBD X BOX Ltd has launched its unique Selective OBD code Deleter. Supplied to industry professionals only, it’s a brand new two-stage diagnostic concept. As the Technicians Tool is initially used, it auto refreshes at up to once per second, both pending and registered fault codes. These can be automatically deleted and allow limp-mode to be temporarily overridden for diagnostic purposes.

Overriding limp-mode can be used to help clean blocked DPFs, while also solving any sticking turbochargers and EGR valves. Some Emergency Breakdown Services, for example the AA, RAC or Green flag, will find the OBD X BOX useful in keeping vehicles driveable while reducing their recovery costs.

The much smaller low cost Fix Assist module is programmed by the Technicians Tool to also delete selected OBD codes; this can be temporarily or permanently installed to the vehicie. Should a further non-selected fault code appear, the OBD X BOX pauses deletion allowing the EML to come back on. This alerts the driver that some new and maybe more important fault codes may be present.

The OBD X BOX records individual OTC frequencies and can be set to pause deletion when a selected max code delete counter is reached. This assists Garages in when to re-book vehicles for repairs based on their DC re-occurrence.

Its unique DTC Alerter feature bleeps when a DTC occurs, which alerts the technician or customer to make mental notes of precisely when an intermittent fault occurred. Analysing under what engine temp. load. RPM and driving conditions a pending fault occurred (even without the EML on) can often help technicians to re produce and fix the fault.

Bert Clegg Managing Director says this remarkable new tool takes fault diagnosis to a new level.

Full technical details and video are available here.