What is engine trouble code 42 for a 95 Chevy silverado?

There isn't a universally standardized OBD-II trouble code 42. OBD-II systems (which became mandatory in 1996) use a 3-digit or 5-digit code system. A 1995 Chevy Silverado uses a pre-OBD-II system, which means the codes are manufacturer-specific and not standardized across different makes and models. Code 42 would be unique to General Motors' system for that year and model.

To find out what code 42 means for your 1995 Chevy Silverado, you need to consult:

* Your vehicle's repair manual: This is the best source. It will have a section dedicated to diagnostic trouble codes specific to your truck's year and engine.

* A GM service manual for that year: These are available online (often as PDFs) or from automotive repair supply stores.

* A Haynes or Chilton repair manual: These are more general but may contain information on your vehicle's diagnostic system.

Without access to one of these resources, it's impossible to say what code 42 means for your specific vehicle.