Unfortunately any modern vehicle will almost certainly suffer a fault of some kind during its life (hopefully during the warranty period when you don’t have to pay for it to be fixed) and rattles and water leaks are the two most difficult faults to find.
There are many ways to find the fault and we use the following tools to help us get to the bottom of the problem
Diagnostic computer which plugs directly into the engine Electronic Control Unit (engine ECU)
Autodata software (information database) giving us fixes to known problems associated with a particular model of vehicle.
It all starts with accurate information gathering from the driver (probably the most important aspect). In some cases, it can often be easier to demonstrate the fault directly to the technician, especially if the fault is intermittent and only occurs under specific conditions. If the solution to the problem is not obvious, then we would need to spend a little symptomatic time on the vehicle, by plugging in several different diagnostic equipment into your vehicle.