Visual Check & Vehicle Preparation

Before connecting any equipment to diagnose electronic engine control system, perform following preparatory procedures:

• Verify condition of air cleaner and air ducts.
• Inspect all vacuum hoses for leaks, restrictions, or improper routing.
• Inspect electrical system for corrosion, bent or broken pins, loose wires or terminals, or improper routing.
• Inspect PCM, sensors, and actuators for physical damage.
• Check engine oil and coolant level.
• Observe all necessary safety precautions to prevent personal injury or vehicle damage.
• Set parking brake. Position shift lever into Park for automatic transmissions, or Neutral for manual transmissions. DO NOT  move shift lever during test unless specifically directed.
• Turn off all lights and accessories. Ensure vehicle doors are closed when measuring voltage or resistance.
• Start engine. Run at idle until upper radiator hose is hot and pressurized and engine is off fast idle. Inspect for leaks around exhaust manifold, exhaust gas oxygen sensor, and vacuum hose connections.
• Turn ignition off. Service items as required. Go to EQUIPMENT HOOK-UP below.