Frequently Asked Questions

Tools do not fix faults. People fix faults using tools.

Good tools make it much easier to fix problems. The better diagnostic tools don't just read and clear fault codes, they also show live data and an array of vital information for analysis and fault diagnosis.

In practise, most hand-held EOBD readers are not updated because their functions do not change, therefore no updates are produced for them. However, the more expensive top level professional diagnostic systems can normally always be updated to provide extra functionality. Updates for professional diagnostic tools can be expensive but genuinely essential updates are not frequently necessary

Not if the tool is only an engine fault code reader as they do not have functions for any systems outside the engine. Engine Fault Code readers are available with functions for extra systems outside the engine, however, separate tools are normally required to link to each system in the car

The MIL is the “Malfunction Indicator Light.” It is also often referred to as the Engine Management Light or Engine Warning Light. The light switches on when the diagnostic system in a car detects a problem and stores a fault code.

The tool must be compatible with the diagnostic system in each car. There are tools available to link with both systems EOBD and older systems however they are usually much more expensive. It is imperative that you always make sure the diagnostic tool is compatible with the diagnostic system in the car as it is essential that the tool and the system match, otherwise it's impossible to get a link between the tool and the car

A diagnostic interface is more commonly known as a "diagnostic cable." One end of the cable is connected to a laptop, and the other end is plugged into the diagnostic port of a vehicle. This then enables the diagnostic data to be directly viewed on the laptop screen.

Freeze Frame is a snapshot of the car system taken at the exact time the car developed a fault. The snapshot is stored in the vehicle and shows the technician exactly what it was doing immediately before the engine warning light was triggered.

The technician can then compare the information with the manufacturers default settings to identify the cause of the problem.

Live Data should show you the cause of vehicle malfunctions when you connect a diagnostic tool and run the engine. It will show various sensor values alongside other information when the engine is running which you can then compare with the manufacturers default settings. By comparing the data from the car with the manufacturers default settings, you usually identify the problem.

The most common fault codes are known as Powertrain codes, or P codes. However, there are alos B Codes (Body Codes) and C Codes (Chassis Codes).

Generic P codes all start with "P0" and their categories are split into the following:

P0001 - P0099: Fuel and Air Metering & Auxiliary Emission Controls

P0100 - P0199: Fuel and Air Metering

P0200 - P0299: Fuel and Air Metering (Injector Circuit) 

P0300 - P0399: Ignition System or Misfire 

P0400 - P0499: Auxiliary Emissions Controls 

P0500 - P0599: Vehicle Speed Controls and Idle Control System 

P0600 - P0699: Computer Output Circuit 

P0700 - P0899: Transmission 

B codes all begin with "B0" and cover side airbags, seatbelt tension, seatbelts, seat recliners and seat sensors etc

C codes all begin with "C0" and cover mechanisms outside of the actual body of the car such as brakes, the suspension, steering, tyres and exhaust

Manufacturers trouble codes usually begin with the prefix “P1” and are unique to a vehicle of a specific year, make, model and sometimes engine size. They are generated by manufacturers to cover faults not already covered by the generic database. These extra fault codes for the benefit of dealerships which enable them to access more information from the car. There may be over 300 readings available in a car  depending on each manufacturer and each car model.

Basic diagnostic tools will show only the generic OBD and EOBD codes. The more expensive diagnostc tools can show the full range of generic codes and usually all of these extra manufacturers enhanced codes. 

Generic Fault Codes are codes that mean the same in all cars, regardless of manufacturer.

It is the diagnostic standard for European cars based on the original American OBD2 standard. EOBD is used in most new petrol cars from 2001 and most diesel cars from 2004.