(Automotive engineering: Design and performance) Diagnostic testing is the testing of a vehicle, or one of its systems or parts, in order to identify why it is not working properly.
⇒ A facility offering diagnostic testing will give you specific information about how well the carburetor, battery, alternator,
etc, are functioning. ⇒ Diagnostic testing showed that the engine produced less power than expected because the ignition timing
was too retarded. ⇒ He was unable to find why his car ran unevenly, so he took it to the dealer for diagnostic testing.
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