Summary
P0141 means the heater circuit in the downstream O2 sensor on Bank 1 (the post-catalytic-converter sensor) has failed. The downstream sensor monitors catalytic converter efficiency and needs its heater to reach operating temperature quickly. The most common cause is a burned-out heater element inside the sensor (60%), followed by a blown fuse (15%) and wiring damage (15%). Fix is usually the sensor itself: $20–$100 part, 20–45 min job.
Severity: Low — the downstream sensor monitors converter health, not fuel control
Safe to drive: Yes
Repair cost: $20–$200 depending on cause
DIY difficulty: Easy to Moderate
What does P0141 mean?
The Bank 1 downstream (post-cat) O2 sensor monitors catalytic converter efficiency. Like all O2 sensors, it has an internal heater to reach operating temperature (~600°F) within seconds of starting the engine. P0141 sets when the PCM detects the heater circuit is drawing no current (open circuit), excessive current (short), or the sensor isn't reaching operating temperature within the expected time.
Unlike the upstream sensor (P0135), the downstream sensor doesn't directly control fuel delivery. It's used for catalyst monitoring. A failed heater means the converter efficiency check is delayed until exhaust heat warms the sensor, and the PCM can't complete its catalyst monitor as quickly.