1/I O2 Sensor Slow Response (OBD II)
1/1 UPSTREAMName of code:
O2 Sensor Slow Response
When Monitored:
With the engine temperature greater than 147 degree F, after reaching a vehicle speed of 10 mph and the throttle remaining open (off idle) for two minutes, bring the vehicle to a stop and allow the engine to idle with the transmission in drive (auto) or in neutral (manual).
Set Condition:
The oxygen sensor signal voltage is switching from below 0.27 volts to above 0.62 volts and back fewer times than required.
Theory of Operation:
Effective control of exhaust emission is achieved by at oxygen feedback system of which the most important element is the oxygen sensor (O2S), which is located a the exhaust path. Once the sensor reaches its normal operating temperature of 300° - 350°C (572° - 662°F), it generates a voltage inversely proportional to the amount of oxygen in the exhaust. Response rate is the time required for the sensor to detect changes in the exhaust gas oxygen content it switches from lean to rich if it is exposed to richer than optimum A/F mixture or vice versa the O2s output voltage ranges from 0 to 1 volt. A good sensor easily generates an output voltage in this range as it is exposed to different oxygen concentration. To detect in the shift in the A/F mixture (lean or rich) the output voltage has to change beyond a threshold value. A malfunctioning sensor could have difficulty changing beyond thresholds.
Possible Causes:
- Exhaust leak
- Fuel contamination
- O2 sensor failure
- Electrical wiring connectors
- Electrical mechanical
- O2 heater failure
NOTE: The above calibrations are approximate values.