Circuit Description
WARNING: This page is about a different car, the 2000 Isuzu Hombre. However, it is still accessible from the selected car via links, so may be relevant.
Vehicle Control Module (VCM) provides about 0.45-volt reference to HO2S high and low circuits. HO2S sensor signal voltage varies from about one volt when exhaust is rich to about 0.1 volt when exhaust is lean. When ignition is turned on, battery voltage is supplied to HO2S heater to provide for faster sensor warm-up, thus allowing sensor to become active in a shorter period of time. VCM reads amount of time necessary for sensor to become active after start-up.
Conditions required to set DTC are:
- MAF less than 27 grams per second.
- Engine running greater than 2 seconds.
- ECT and IAT less than 89.6°F (32°C).
- Difference between ECT and IAT no greater than 41°F (5°C).