Circuit Description

Heated Oxygen Sensor (HO2S) 2 refers to bank 1 sensor 2. When ignition is turned on, battery voltage is supplied to HO2S 2 heater to provide for faster sensor warm-up, thus allowing sensor to become active in a shorter period of time. PCM reads amount of time necessary for sensor to become active after start-up.

Conditions required to set DTC are:

• No ECT, IAT, MAF, MAP or TP sensor DTCs set.
• No EVAP system DTC set.
• No fuel injector circuit, fuel trim, misfire or transaxle DTCs set.
• MAF less than 24 grams per second.
• ECT and IAT less than 95°F (35°C) at start-up.
• Difference between ECT and IAT no greater than 11°F (6°C).
• HO2S 2 voltage remains within 0.15 volt of bias voltage (about 0.45 volt) for longer amount of time than it should.