O2 Sensor Heater Circuit Malfunction (Bank 1 Sensor 3)
The oxygen sensor heater in your exhaust (Bank 1, position 3) isn't working properly, like a broken heating element in a toaster that can't warm up. The ECU detected the heater circuit isn't drawing the expected electrical current to warm the sensor.
The ECU monitors the O2 sensor heater circuit current draw during startup and operation. The heater must reach operating temperature quickly so the sensor can produce accurate readings for fuel trim calculations. If heater resistance is abnormal or open, the ECU triggers this fault.
| Parameter | Normal Range | Fault Condition |
|---|---|---|
| Heater circuit current | 0.5–2.5 amps during warm-up | Below 0.1 amp or open circuit detected |
| Heater response time | Reaches operating temp within 10–20 sec | No temperature rise or excessive delay |
Code P0150 is a moderate fault. You can generally drive to a workshop, but avoid long trips or high-load driving (motorway, uphill towing) until it is diagnosed. If the code keeps returning after clearing, or if you notice the symptoms listed above worsening, do not delay professional diagnosis. Many moderate codes have multiple possible root causes — a mechanic with live OBD data can identify the exact fault more efficiently than part-by-part trial and error.
Once the fault is repaired, P0150 can be cleared using any OBD-II scanner. Connect the scanner, navigate to "Clear Codes" or "Erase DTCs," and confirm. The check engine light turns off immediately.
The code will return if the root cause was not actually fixed. The ECM re-detects the fault within 1–3 drive cycles and sets the code again.