HB - Testing Notes

Testing Schematic:

DESCRIPTION

The Heated Oxygen Sensor (HO2S) reacts with the oxygen in the exhaust gases and generates a voltage based on this reaction. A low voltage indicates too much oxygen or a lean condition. A high voltage indicates not enough oxygen or a rich condition. The fuel injector is a typical on/off device. The amount of fuel delivered is determined by how long the injector is held open.

NOTE: You should enter this Pinpoint Test only when you have been directed here from Quick Test or Pinpoint Test S.

REMEMBER

To prevent the replacement of good components, be aware that the following non-EEC areas may be at fault:

- Ignition System

- Electrical System

- Evaporative Emission (EVAP) System

- Fuel System

- Positive Crankcase Ventilation (PCV) System

- Intake Manifold Leaks

- Exhaust Gas Recirculation System

- Exhaust Manifold System Leak/Plugged

- Air Intake System/Filter

- Engine Cooling System

- Fuel and Engine Oil Contamination

- Base Engine

This Pinpoint Test is intended to diagnose only the following:

- HO2S/heater

- Fuel injector

- HO2S Connection

- Powertrain Control Module (PCM)

- Vacuum Systems

- Harness circuits: HO2S GND, HO2S, INJ. 1-6, VPWR and SIG RTN

- Cold Start Injector