Jeep Wrangler Owner's Manual

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Onboard Diagnostic System — OBD II
Your vehicle is equipped with a sophisticated onboard diagnostic system called OBD II. This system monitors the performance of the emissions, engine, and automatic transmission control systems. ...

Selection Of Lubricant
Use only the manufacturer’s recommended fluid. Refer to “Fluids, Lubricants, and Genuine Parts” in “Maintaining Your Vehicle” for further information. ...

Materials Added To Engine Oil
Do not add any supplemental additives, other than leak detection dyes, to your engine oil. Engine oil is an engineered product and its performance may be impaired by supplemental additives. ...