P0141 – O2 Sensor Heater Circuit Malfunction (Bank 1 Sensor 2)
What does P0141 mean?
The heater circuit in the downstream oxygen sensor (Bank 1, Sensor 2 — located after the catalytic converter) is malfunctioning. This sensor monitors converter efficiency rather than controlling fuel mixture, and its heater brings it to operating temperature quickly.
What causes P0141?
Listed from most to least common:
- 1Failed heater element in the downstream O2 sensor
- 2Blown fuse in the heater circuit
- 3Damaged or corroded wiring/connector near the exhaust
- 4Relay fault
Code breakdown
Common symptoms
- Check engine light on
- Normal drivability in nearly all cases
- Emissions monitors may not complete, causing an inspection failure
How to diagnose
- 1Check the relevant fuse first.
- 2Inspect the connector and wiring for heat or road damage — this sensor sits under the vehicle and is exposed.
- 3Measure heater resistance and compare against specification.
- 4Confirm voltage is present at the heater circuit.
Minimal drivability impact, but it prevents the catalyst monitor from running and will fail an emissions test.
Common fixes and estimated costs
| Repair | Estimated cost |
|---|---|
| Replace fuse | $5–$20 |
| Repair wiring/connector | $80–$300 |
| Replace downstream oxygen sensor | $130–$350 |
Costs are rough US estimates including parts and labor. Actual pricing varies significantly by vehicle, region, and shop rates.
Good to know
Because this sensor is mounted underneath the vehicle, wiring damage from road debris and corrosion is more common than on the upstream sensor. Inspect the harness carefully before buying a new sensor.
Related codes
This information is provided for general reference only and may vary by manufacturer, model, and year. It is not a substitute for professional diagnosis or repair.