Test Description

NOTE: Test numbers refer to numbers on diagnostic chart.

Code P0135 (HO2S HEATER CIRCUIT MALFUNCTION) can cause Code P0133 to set. Repair heater circuit before proceeding with this chart.
An exhaust leak 6-12" away from sensor in either direction can cause Code P0133 to set. Thoroughly inspect exhaust system for leaks.
A sensor that is contaminated by oil will be Dark Brown in appearance. A sensor that is contaminated by coolant will be Whitish Green in appearance.
Certain RTV silicone gasket materials release vapors that can contaminate sensor. Silicone in fuel can cause silica contamination. If sensor appears to be contaminated by silica, and all other sealants are non-silica base, advise customer to select a different fuel company. A missing fuel filler restrictor indicates leaded fuel may have been used.

Fig 1: Code P0133 Schematic (Corvette) Bank 1 HO2S No. 1 Circuit Slow Response

Fig 2: Code P0133 Flow Chart (Corvette) Bank 1 HO2S No. 1 Circuit Slow Response