The heated oxygen sensor (HO2S) monitor tracks the rate of voltage change during the rise and fall of the HO2S signal. When the rate of voltage change is less than a calibrated value, the PCM begins to modify the fuel trim attempting to increase the HO2S voltage switch rate. This DTC sets when the PCM is at the allowable limit or has exceeded an allowable length of time for fuel trim modification, without etecting an acceptable rate of voltage change.
Item | Detecting Condition | Possible Cause |
DTC Strategy |
•
Signal check, high | 1. Poor connection 2. HO2S (S2) 3. Leak or clog in intake air system 4. PCM |
Enable Conditions |
•
Dew point end detected
•
Fuel feed back control active
•
Exhaust Gas temperature is higher than 350°C and lower than 800°C
•
No upstream O2 sensor heater error
•
Fuel Cut-off condition
•
Integrated air mass during fuel cut-off > 0.62kg ~ 0.78kg
•
Rear O2 sensor monitoring - completed
•
Rear O2 sensor heater monitoring - completed
•
No misfire
•
No fuel system error, No PCV error
•
No CKP sensor error, No CMP sensor error | |
Threshold Value |
•
S2 signal is higher than 0.15V | |
Diagnostic Time |
•
2 sec. | |
Mil On Condition |
•
3 driving cycles |
※ S1 : upstream oxygen sensor / S2 : downstream oxygen sensor
