P0141: the rear oxygen sensor's heater circuit has a fault
An oxygen sensor only reads accurately once it's hot, so most have a small electric heater built in to bring them up to temperature quickly after a cold start. This code means the electrical circuit for bank 1's rear sensor heater isn't behaving the way the engine control unit expects. It's about the heater, not the sensor's oxygen reading itself.
You might notice
- The engine warning light comes on
- No other symptom you'd notice while driving, since this isn't the sensor the computer uses to fine-tune fuelling moment to moment
- oxygen sensor
- — a sensor in the exhaust that measures how much oxygen is left after combustion
What the code itself says
P0141 is a powertrain (engine, gearbox and drive system) code, and the 0 after the letter means it is a generic code with a standard meaning.
Grouped here as: Engine running, fuelling and misfires — Air metering, fuelling, ignition, misfire, idle, boost, knock, oxygen sensors and the catalyst, all working together in the running engine. That grouping is ours, to help explain the code. The code's official family is the letter at the start.
This page is generic. Your car isn't.
A code on its own only tells you what the sensor saw, not what's actually wrong — and that changes next to your other codes. Read this one together with the rest of your scan and we'll work out what's really going on.
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