P0141
O2 Sensor Heater Circuit Malfunction (Bank 1, Sensor 2)
The heating element inside the downstream oxygen sensor on bank 1 is open-circuit, drawing no current, or drawing too much. Without heater, the sensor takes much longer to reach operating temperature, delaying catalyst diagnosis.
- Check engine light: Yes
- Emissions related: Yes
- Repair difficulty: easy
Symptoms
- Check engine light on after several drive cycles
- Slightly increased fuel consumption during cold start
- Delayed entry into closed-loop fuel control
- Failed emissions inspection (lambda readiness)
Common causes
Ordered by how often each turns out to be the cause.
- Heater element open-circuitCommon
- Heater fuse blownPossible
Parts involved
- Oxygen Sensor Downstream
- Oxygen Sensor Heater Relay
P0141 is a generic OBD-II code defined by SAE J2012. Exact wording and diagnostic procedure vary by manufacturer and model. Code definitions are drawn from the public-domain OBDex dataset; the workshop notes are our own.