P0141: O2 Sensor Heater Circuit (Bank 1 Sensor 2)
Title: SAE J2012 generic definition. Manufacturer-specific definitions and enhanced codes can differ; check service information for the exact vehicle.
What P0141 means
There is a fault in the heater circuit of the downstream oxygen sensor on bank 1 (after the catalytic converter).
What sets it
The downstream sensor's heater is monitored the same way as the upstream one. The downstream sensor is mainly used for the catalyst monitor, so P0141 can stop the catalyst test from running and keep readiness incomplete.
Symptoms
- No drivability symptoms in most cases
- Catalyst readiness monitor may stay incomplete
- Inspection failure
Is it safe to drive?
General guidance, not a guarantee: Safe to drive in normal circumstances. It is mainly an emissions-readiness problem. If in doubt, have it towed and diagnosed.
Common causes
Listed roughly from most to least common in general practice. The real order varies by vehicle, mileage and history.
- Heater element open
- Wiring damaged near the exhaust or by road debris
- Connector corrosion (underbody location)
- Fuse
Test before you replace: diagnostic sequence
General guidance only. Always follow the vehicle manufacturer's service information, specifications and safety procedures. Any figures below are general guidelines that defer to the manufacturer's specification.
- Check the heater fuse.
- Inspect the harness routing under the vehicle. Downstream sensor wiring is exposed to heat, water and debris.
- Measure heater resistance and compare with the manufacturer specification.
- Check power and the ECM control side per the wiring diagram.
- Repair, then drive until the catalyst and O2 heater monitors run and confirm readiness.
Bench note: Because the downstream sensor sits under the car, check the connector for corrosion before you condemn the sensor.
How-to guides for this code
Related codes
FAQ
Will P0141 affect fuel economy?
Usually not much. The downstream sensor mainly monitors the catalyst.
Can I pass inspection with P0141?
Usually not. A stored code and incomplete readiness typically fail OBD-based inspections.
Sources
- SAE J2012, Diagnostic Trouble Code Definitions (standard page; code titles only)
- California Code of Regulations, 13 CCR 1968.2, OBD II requirements (via Cornell LII)
- US EPA, "OBD: Frequently Asked Questions" (EPA-420-F-02-014)
Written with AI assistance and reviewed for accuracy; not a substitute for OEM service information. Shop Docs Studio is not affiliated with SAE, EPA, CARB or any vehicle manufacturer.