[amidgeha]

O2 Sensor Slow Response - Lean to Rich

The Powertrain Control Module (PCM) or Engine Control Module (ECM) continuously monitors the Heated Oxygen Sensor (HO2S) activity. During the monitor period the PCM/ECM counts the number of times that the HO2S responds from rich to lean and from lean to rich and adds the amount of time it took to complete all transitions. With this information, the PCM/ECM can determine the average time for all transitions. If the average response time is too slow, a DTC sets.

Cause:
Faulty Heated Oxygen Bank 2 Sensor 1
Heated Oxygen Bank 2 Sensor 1 harness is open or shorted
Heated Oxygen Bank 2 Sensor 1 circuit poor electrical connection
Inappropriate fuel pressure
Faulty fuel injectors
Intake air leaks may be faulty
Exhaust gas leaks

Symptoms:
Check engine light
High Fuel Consumption
Excessive Smoke from Exhaust