Circuit Description

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. DTC will set if PCM determines that too much time was required for HO2S 2 to become active.

For duplication of DTC, ensure:

• No active misfire, fuel injector circuit, EVAP, EGR, fuel trim, TP, IAT, MAP, ECT, MAF or CKP DTCs are set.
• ECT and IAT are less than 95°F (35°C) at start-up.
• Difference between ECT and IAT is within 43°F (6°C) of each other.
• AIR pump commanded off.
• System voltage 9-18 volts.