OBD-II Code · Sensors
P0141
O2 Sensor Heater Circuit Malfunction (Bank 1, Sensor 2)
Downstream O2 sensor heater failure, bank 1.
Common symptoms
- Check engine light
- Slow sensor warm-up
Likely causes
- Failed O2 heater
- Wiring
- Blown fuse
Where to start
- Try the cheapest cause first. Start by checking: failed o2 heater.
- Cost & scope. $150-$350
- If the code returns after the fix: escalate to a shop or scanner with live-data and freeze-frame. A code that re-sets means the underlying fault is still there.
Read the full diagnostic procedure
P0141 is a heater-circuit fault on bank 1 downstream. Same diagnostic as P0135 upstream but for the post-cat sensor: ohm the heater pins (6-15 ohms cold narrow-band, 2-4 ohms wideband), verify B+ at the heater feed pin key-on, verify the ECU is providing a pulsed ground on the heater control pin. Downstream sensors fail their heaters MORE often than upstream because they live in a harsher thermal environment — sitting just downstream of a cat that hits 800°C+ under load, then cooling rapidly when the engine shuts off. The heater coil's repeated thermal expansion eventually opens it up. Cheapest-first: confirm the fuse that feeds the O2 heaters hasn't blown (often shared across multiple sensors on one fuse, so a shorted heater on ONE sensor can blow the fuse and set P0141 + P0135 + P0155 simultaneously). If the fuse is good and the heater ohms open, replace the sensor.
Vehicle-specific patterns
Vehicle-specific patterns: 2003-2008 Toyota Corolla / Matrix 1ZZ-FE throws P0141 around 110k-130k routinely. 2005-2010 Chrysler 300 / Charger 5.7L Hemi sets P0141 from TIPM relay failures — same TSB as P0135. 2007-2013 Chevy Equinox / Terrain 2.4L Ecotec throws P0141 from corroded downstream connectors (the sensor sits right in the wheel-well spray path). 2009-2015 Subaru Forester / Outback FB25 sets P0141 from a chafed downstream harness against the rear differential mount bolt. Cost band: $150-$350 for sensor; up to $700 if TIPM is involved; under $20 if it's just a fuse.
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