The normal operating temperature of the HO2S(Heated Oxygen Sensor) ranges from 350 to 850°C(662 to 1562°F). The HO2S heater greatly decreases the amount of time required for fuel control to become active. The ECM provides a pulse width modulated control circuit to adjust current through the heater. When the HO2S is cold, the value of the resistance is low and the current in the circuit is high. On the contrary, if the temperature in the resistor of the sensor rises, the current drops gradually.
Checking current from HO2S under detecting condition,if the heater current is below a certain threshold for more than predeterminate time, PCM sets P0141. MIL(Malfunction Indication Lamp) turns on when the malfunction lasts till consecutive 2 driving cycle.
Item | Detecting Condition | Possible cause |
DTC Strategy | ● Monitor the current through the heater | ● Poor Connection ● HO2S(B1/S2) ● PCM |
Enable Conditions | ● Engine Running > 60 sec. ● Heater Duty Cycle > 18% ● Max. Duty Cycle - Min. Duty Cycle < 5% | |
Threshold value | ● Filtered Heater Current < threshold value | |
Diagnosis Time | ● Continuous (More than 2.5 second failure for every 5 second test) | |
MIL On Condition | ● 2 Driving Cycles |
Condition | Current(A) |
Heater Current at 13.5V, 450℃(842°F) Exhaust | 0.52 ± 0.1 |
