DTC P0133 & P0153: Ho2S Circuit - Slow Response - Bank 1 & 2, Sensor 1 (6.0L W/Isolated Ground): Description

WARNING: This page does not describe the selected car, but rather 11 other vehicles, including the 2002 GMC Yukon XL, 2002 GMC Yukon, 2002 GMC Sierra, 2002 GMC Cab & Chassis Sierra, and 2002 Chevrolet Tahoe. However, it is still accessible from the selected car via links, so may be relevant.

This diagnostic applies only to vehicles built with isolated grounded Heated Oxygen Sensors (HO2S). The Powertrain Control Module (PCM) continuously monitors the HO2S activity for 100 seconds. During the monitor period, the PCM counts the number of times that the HO2S responds from rich to lean and from lean to rich and adds the amount of time necessary to complete all transitions. With this information, the PCM can determine the average time for all transitions. If the average response time is too slow, a Diagnostic Trouble Code (DTC) sets. The PCM determines the lean to rich transition when the HO2S voltage changes from less than 300 mV to more than 600 mV. The PCM determines the rich to lean transition when the HO2S voltage changes from more than 600 mV to less than 300 mV.