The linear O2 sensor is mounted on the front side of the Catalytic Converter (warm-up catalytic converter) or in the front exhaust pipe. It detects a wide range of air/fuel ratios in the exhaust gas from the rich to lean regions. This linear O2 sensor produces a current that corresponds to a specific air/fuel ratio. The PCM monitors this signal and determines whether the air/fuel mixture is rich or lean. The PCM constantly monitors the linear O2 sensor and increases or decreases the fuel injection duration using this signal. This is called closed-loop fuel control operation.
The PCM monitors front oxygen sensor amplitude level and compares it to predetermined minimum amplitude value which could increase emission or disturb lambda control by the effect of aging on the oxygen sensor. The PCM sets DTC P0133 when the amplitude of oxygen sensor is equal to or less than minimum amplitude threshold.
Item
Detecting Condition
Possible Cause
DTC Strategy
Lambda Regulation Frequency Check
Leak in intake or exhaust system.
Poor connection or damaged harness
HO2S contamination
Enable Conditions
400°C < Modeled catalyst temp. < 900°C
Lambda regulation active
Engine speed < 3400 rpm
200 mg/rev < Engine Load < 700 mg/rev
Coolant temperature > 74°C(165°F)
3 mph < Vehicle speed < 112 mph
Canister purge closed
No relevant failure
11V<Battery voltage
Threshold Value
Average Ratio between measured and maximum allowed frequency during 100 Lambda regulation cycles > 0.95
Diagnostic Time
20 Forced stimulation cycles
Mil On Condition
2 Driving Cycles
Test Condition
GDS Parameter
O2 SNSR VOL.-B1/S1
O2 SNSR VOL.-B1/S2
Normal Value when circuit is normal
Idle after warm up
Signal is switching from rich(above 0.45V) to lean(below 0.45V) a minimum of 3 times in 10
above 0.7V
HO2S(B1S1) signal circuit open
Approx. 0.43~0.45V
-
HO2S(B1S2) signal circuit open
Normal value with idle after warm up : Signal is switching from rich(above 0.45V) to lean(below 0.45V) a minimum of 3 times in 10 seconds.
GDS display with open in signal circuit : Approx. 0.43~0.45V