Enhance Testing

P0038 - HO2S Heater Circuit High (B1/S2)





General Description
The normal operating temperature of the HO2S (Heated Oxygen Sensor) ranges from 350 to 850 degrees C (662 to 1562 degrees 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.

DTC Description
Checking current from HO2S under detecting condition,if the heater current is below a certain threshold for more than predetermination, PCM setsP0030. MIL (malfunction Indication Lamp) turns on when the malfunction lasts till consecutive 2 driving cycle.

Detecting Condition and Specifications





Signal Waveform





Wiring Schematic