O2 Sensor Heater Bank 1 Sensor 2
P0141 points to the heater circuit for the downstream oxygen sensor after the catalytic converter on bank 1.
It usually does not cause major drivability symptoms, but it can affect catalyst monitoring and emissions readiness.
Common symptoms
- Check engine light
- Failed emissions readiness
- Usually drives normally
- Possible fuel economy drop
Likely causes
- Failed downstream O2 sensor heater
- Damaged exhaust-side wiring
- Blown fuse
- Poor connector contact
- Rare PCM fault
What to check before replacing parts
Inspect sensor wiring near exhaust heat
Look for: Look for cracked, melted, or heat-discolored insulation on the downstream sensor harness — repeated heat cycling near the exhaust is the most common cause of an open heater circuit here.
Check the heater fuse
Look for: A blown fuse cuts power to the heater circuit; if it's blown, look for a chafed wire or shorted heater element causing it rather than just replacing the fuse.
Measure heater element resistance
Look for: Infinite resistance (open) or a reading far outside the expected range confirms the heater inside the sensor itself has failed.
Verify power and ground at the connector
Look for: Missing voltage when commanded on, or a bad ground, points to a wiring or driver-circuit fault rather than the sensor.
Confirm sensor position before replacement
Look for: Sensor 2 is the downstream sensor after the catalytic converter on bank 1 — double-check this against the vehicle's actual layout so you don't order the wrong part.
This page explains the generic P0141 definition and is general reference information, not a diagnosis for your specific vehicle. Actual causes, severity, and repairs vary by make, model, engine, and mileage — always confirm with a scan tool and a qualified technician before replacing parts.
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