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.
The PCM determines if a front HO2S heater fault has occurred and sets DTC P0030 if the front HO2S heater control driver inside the PCM fails, if HO2S is not operational (after an elapse of predetermined time) since engine start, or when the front HO2S tip temperature is out of normal working range.
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 | ● Sensor preheating and full heating phases finished ● Time after start elapsed:240 sec. ● 11V＜Battery voltage＜16V ● 1%＜Heater power＜99% ● Exhaust gas temp. model＜650°C (1,202°F) | |
Threshold Value | ● O2 sensor Element Resistance ＞2100 Ohm | |
Diagnostic Time | ● 5 min. | |
Fail-Safe | ● EVAP. emission control function is controlled in minimum operation mode |
Temp.(℃) | Temp.(℉) | Front HO2S Heater Resistance(Ω) | Temp.(℃) | Temp.(℉) | Front HO2S Heater Resistance(Ω) |
20 | 68 | 9.2 | 400 | 752 | 17.7 |
100 | 212 | 10.7 | 500 | 932 | 19.2 |
200 | 392 | 13.1 | 600 | 1,112 | 20.7 |
300 | 572 | 14.6 | 700 | 1,292 | 22.5 |
