P0150
O2 Sensor Heater Circuit Malfunction (Bank 1 Sensor 3)
Powertrain Emission Controls O2 Sensor Heater 🟡 Moderate — Fix within a week
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What This Actually Means
In plain language — no jargon

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.

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Symptoms You May Notice
3 known symptoms for this code
Check Engine Light illuminated
Sluggish acceleration or reduced fuel economy
Rough idle or hesitation during acceleration
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Embedded Systems Insight
What the ECU/ECM is actually computing

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.

Voltage & Parameter Thresholds

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
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Diagnostic & DIY Fix Guide
Check these in order — from cheapest to most complex
1
O2 sensor connector
Inspect and clean the connector pins for corrosion or water intrusion, then reseat firmly.
2
O2 sensor heater wiring harness
Check wires for breaks, chafing, or loose splices between sensor and ECU; repair or resolder as needed.
3
Oxygen sensor (Bank 1, Sensor 3)
If wiring and connections are sound, replace the sensor itself as the heater element has likely failed.