P0141: O2 Sensor Heater Circuit Malfunction (Bank 1, Sensor 2)
P0141 is the rear-sensor version of P0135, and in the short term it matters even less, because the rear sensor doesn't control your fuel mixture. What earns it a proper page is the pattern that tends to follow: a rear sensor whose heater has died is a rear sensor on the way out, and the next chapter of that story is often the far more expensive-sounding P0420.
What P0141 actually means
Sensor 2 on Bank 1 is the oxygen sensor after the catalytic converter. Its job is monitoring, not fuel control: it watches whether the cat is doing its work. Like the front sensor, it carries an internal heater for fast warm-up, and when the computer sees an open or shorted heater circuit it stores P0141: O2 Sensor Heater Circuit Malfunction, Bank 1 Sensor 2.
Can you keep driving?
Severity: 2 out of 5. Yes, comfortably. Engine running is unaffected because this sensor only observes. The consequences are a lit lamp, a paused catalyst monitor, and the inspection problem those create.
What causes P0141 (most likely first)
- A burnt-out heater in the sensor. Age does it. Past 150,000 km this is the expected outcome.
- A blown fuse shared with other heater circuits. If P0135 arrived in the same moment, check the fuse before anything else; two heaters dying simultaneously is a fuse, not a coincidence.
- Wiring damage. The rear sensor's loom runs along the underbody, exposed to road debris, heat and, on off-roaders, everything a fire trail can throw at it.
Symptoms you'll notice
None, beyond the light. This sensor's failure is invisible from the driver's seat, which is exactly why it's easy to ignore and exactly why the inspection lamp exists.
What it costs to fix in Australia
| Repair | Typical cost (AUD) |
|---|---|
| Fuse | $5 |
| Rear O2 sensor, aftermarket, fitted | $150–300 |
| Rear O2 sensor, genuine, fitted | $250–450 |
| Wiring repair | $100–300 |
Rear sensors are usually cheaper and easier to reach than fronts, which makes this one of the smaller bills in the library. The main labour risk is a sensor seized in the exhaust bung on a rusty coastal car, where a ten-minute job can become an hour of penetrating oil and patience.
The P0420 connection
Here's the part worth the price of admission. A rear sensor with a dead heater still produces readings once exhaust heat warms it, but they're slow and skewed, and a slow, skewed rear sensor is the number one false trigger for the catalyst efficiency code. Plenty of cars have received a catalytic converter they didn't need because a $200 rear sensor was quietly dying first. If P0141 has been in memory and P0420 appears later, replace the sensor and re-test before anyone mentions the word converter.
P0141 on Australian cars
Camry, Corolla, Falcon, Commodore: the usual high-kilometre crowd. Utes and 4WDs add the wiring cause; a Prado or HiLux that's been touring can come home with a rear sensor connector full of bulldust or a loom nicked by a stick, and the code appears a week later on the school run.
Will P0141 fail rego or a roadworthy?
Through the lamp, yes: NSW pink slips on cars over five years, and sale-time certificates in Victoria and Queensland. There's a second, sneakier inspection angle. This sensor runs the catalyst readiness monitor, so a dead heater can leave that monitor incomplete indefinitely, which an examiner with a scan tool reads the same way as a recently cleared code.
How to read and clear P0141
Read everything stored, note any companion heater codes, and check the fuse before ordering parts. After the fix, the heater test passes on the first cold start, so the lamp staying off is quick confirmation; a scanner will also show the catalyst monitor completing over the following days. More codes live in the fault code library.
P0141 FAQ
Is P0141 the front or rear sensor?
Rear. Sensor 2 always means downstream of the catalytic converter; the front sensor's heater code is P0135.
Does P0141 affect performance or economy?
No. The rear sensor monitors the cat rather than controlling fuel, so the engine drives identically with it dead.
Can P0141 cause P0420?
Indirectly and often. A degraded rear sensor skews the catalyst efficiency test, and replacing it clears a surprising share of P0420 complaints without touching the converter.
Can I just leave P0141?
Mechanically you could for months. Practically, the lit lamp fails inspections and masks any new code that appears behind it, so the cheap fix is worth doing.
Related codes: P0135 · P0420 · P2096 · Full fault code library
A fault code is a starting point, not a diagnosis. The same code can have different causes on different vehicles, and any costs shown are typical Australian ranges only. Always have the fault confirmed by a qualified mechanic before buying parts or booking repairs.