Circuit Description

The exhaust pipe oxygen sensor monitors exhaust gas oxygen content and delivers an input signal to ECM. The ECM uses input signal to determine fuel injection system operation. Code is set when manifold mounted oxygen sensor signal voltage is .45 volt or more and exhaust pipe mounted oxygen sensor signal voltage is .45 volt or less under the following conditions:

• Engine coolant temperature is 176°F (80°C) or greater.
• Accelerator pedal is fully depressed for 2 seconds or more.