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.
The ECM determines when a rear HO2S heater fault occurs and sets DTC P0036 if measured rear HO2S resistance is lower than the predetermined threshold.
Item | Detecting Condition | Possible Cause |
DTC Strategy | ● Evaluate O2 sensor element temperature via measuring element resistance | ● Related fuse blown or missing ● Heater control circuit open or short ● Power supply circuit open or short ● Contact resistance in connectors ● Faulty HO2S |
Enable Conditions | ● 1% < Heater power < 99% ● Time after start elapsed : 240 sec. ● 11V<Battery voltage<16V ● Exhaust gas temp.model<650℃(1, 202℉) ● No relevant failure | |
Threshold Value | ● HO2S Element Resistance > 1100 Ohm (Catalyst Temperature < 500°C(932℉)) | |
Diagnostic Time | ● 5 min. | |
MIL On Condition | ● 2 Driving Cycles |
Temp.(°C) | Temp.(°F) | Heater Resistance (Ω) |
18~20 | 64~82 | Approx. 9 |
