What are diagnostics?

There is a common misconception that a vehicle code read is the same as vehicle diagnostics. The issue with this is that when a warning light comes on, it is because one of the vehicles control units has a fault code due to a component or wiring issue that is no longer within manufactures tolerances built into the control units. This is where a code read often happens. Unfortunately a code in a control unit does not necessarily mean that the component the code is relating to is at fault.

Where a diagnostic test procedure differs from a code read is due to what happens after a code has been extracted from a control unit. A code read stops after that and can cause unnecessary replacement of components due to no diagnostic test procedures being carried out. Diagnostic test procedures are more in-depth, and all possible components are tested individually to confirm the correct function and signals to the control units. By testing all components relating to a trouble code, we are able to identify and repair the correct components rather than fitting a part and hoping it will fix it. We also test any repairs carried out after to confirm that the repair has resolved the issue.

Do I need to have my vehicle diagnosed straight away?

This is a question that is asked a lot. Our answer is always the same: we advise that all warning lights or unusual noises are investigated as soon as convenient, for numerous reasons. Firstly, it could potentially save money in the long term due to one component failure leading to overexertion of other components. In certain cases, components becoming over stressed causing premature failure due to having to compensate for the original component failure. Furthermore, when a warning light is illuminated on the dash it can cause a decrease in fuel economy due to the fault. Fixing this early will improve your vehicle’s fuel economy, returning it as close to the manufacturer’s specifications as possible. Finally, if you have a modern diesel vehicle fitted with a DPF (Diesel Particulate Filter), a fault code in the engine control unit will prevent the DPF from regenerating, therefore causing it to block and in turn result in an expensive repair bill.

Colin Post Motor Engineers vehicle diagnostics service:

  • State of the art diagnostic equipment that is constantly updated.
  • Constant training of mechanics to efficiently and effectively diagnose faults on vehicles.
  • 98% first time fix rate.
  • Test procedures carried out before and after repairs to confirm fault has been correctly repaired.
  • Print outs available.
  • Free advice given in regards to faults.
  • 99% vehicle coverage of all electrical systems from battery testing through to control module repair/replacement.