Mechanics That Have No Specialised Diagnostic Equipment, But Need To Check The Status Of The Engine Management System Before Service Work . Mechanics That Are Skilled In Diagnostics But Need A Very Quick Test Tool Before Becoming More Deeply Involved. The Tester Has A Simple Cable With Croc-Clip Battery Connection And One Signal Lead Terminated With A 4 Mm Plug. The User Will Need To Connect The Signal Plug To The Harness And We Recommend The Use Of Mini Break-Out Boxes Or Wire-Piercing Probes. These Connectors And Probes Are Not Included In The Kit To Keep The List Price At A More Modest Level, And Because If A User Purchases More Than One Type From This Series He Would Replicate The Connectors Several Times. What this tool is for: This tool allows you to get a quick check of the quality of the electrical signal created at the Throttle Pot [potentiometer] in a petrol engine management system.When to use this tool: When a vehicle has poor or erratic acceleration, When a vehicle has poor fuel consumption