The normal operating temperature of the HO2S(Heated Oxygen Sensor) ranges from 350 to 850℃(662 to 1562℉). The HO2S heater greatly decreases the amount of time required for fuel control to become active. The PCM 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.
PCM sets DTC P0031 if the PCM detects that the front HO2S heater control circuit is short to ground.
Item | Detecting Condition | Possible Cause |
DTC Strategy |
•
Electrical Check | 1. Related fuse blown or missing 2. Open or short to ground in power circuit 3. Short to ground in control circuit 4. Poor connection or damaged harness 5. Faulty HO2S |
Enable Conditions |
•
10V < Battery voltage < 16Vs
•
1.5% < Heater power < 98.5%
•
Exhaust gas Temp. > 300°C (572℉) | |
Threshold Value |
•
Short to ground | |
Diagnostic Time |
•
1 seconds | |
Mil On Condition |
•
2 Drive Cycles |
HO2S Heater | Normal Parameter |
18 ~ 20℃ | |
Heater Resistance | 2.4~2.9Ω |
