Heater element inside the downstream oxygen sensor has failed (open, internal short, or high resistance). Wiring or connector problem in the heater circuit: open, short to ground, or high resistance. Blown heater fuse or a power-supply problem to the sensor (check your service manual for the circuit). Not usually the catalytic converter: OBD-Codes.com notes a failed converter typically sets P0420 instead.

Replace the Bank 1 Sensor 2 oxygen sensor if its heater is open or shorted (an internal fault can't be repaired). Repair damaged wiring or connectors in the heater circuit. Replace a blown fuse, and find out why it blew. Fix any exhaust leak ahead of the sensor.

P0141🌫 Emissions / oxygen sensorsDrive with caution, fix soon

P0141: O2 Sensor Heater Circuit (Bank 1, Sensor 2) (Meaning, Causes, Fixes)

Q: What does P0141 mean?

P0141 means the engine computer has decided the heater inside the downstream (after the catalytic converter) oxygen sensor on Bank 1 isn't doing its job. A failed sensor heater is the usual cause, followed by wiring or connector problems. Sensor 2 is the downstream oxygen sensor, mounted after the catalytic converter on Bank 1 (the side of the engine with cylinder #1; a 4-cylinder has only Bank 1). Its main job is checking how well the catalytic converter is working. Like the upstream sensor, it only reads accurately when hot, so it has a built-in electric heater. OBD-Codes.com explains that the engine computer times how long the sensor takes to start switching after a cold start; if too much time passes (judged against coolant temperature), it sets P0141. RepairPal describes it as the PCM detecting that the heater isn't operating, or the rear sensor not showing the expected signal activity within the required time. P0135 is the same heater fault on the upstream sensor (Bank 1, Sensor 1), and P0161 is the Bank 2 Sensor 2 heater.

Q: Can I keep driving with P0141?

Drive with caution, fix soon. Usually drivable. RepairPal rates it Moderate: not an immediate safety threat, but get it diagnosed within a reasonable time. Often the check engine light is the only sign, but RepairPal notes the car may fail an emissions test, so don't leave it until inspection day.

Reviewed 2026-10-22 · Based on 2 cited source(s)

What P0141 means

Sensor 2 is the downstream oxygen sensor, mounted after the catalytic converter on Bank 1 (the side of the engine with cylinder #1; a 4-cylinder has only Bank 1). Its main job is checking how well the catalytic converter is working. Like the upstream sensor, it only reads accurately when hot, so it has a built-in electric heater. OBD-Codes.com explains that the engine computer times how long the sensor takes to start switching after a cold start; if too much time passes (judged against coolant temperature), it sets P0141. RepairPal describes it as the PCM detecting that the heater isn't operating, or the rear sensor not showing the expected signal activity within the required time. P0135 is the same heater fault on the upstream sensor (Bank 1, Sensor 1), and P0161 is the Bank 2 Sensor 2 heater.

Severity: can I keep driving?

Drive with caution, fix soon

Usually drivable. RepairPal rates it Moderate: not an immediate safety threat, but get it diagnosed within a reasonable time. Often the check engine light is the only sign, but RepairPal notes the car may fail an emissions test, so don't leave it until inspection day.

Common symptoms

Check engine light on (often the only symptom)
In many cases nothing else is noticeable (RepairPal)
Poorer fuel economy (OBD-Codes.com)
May fail an OBD2 emissions test (RepairPal)

Likely causes

Roughly most to least common, based on the sources below. Your vehicle may differ.

Heater element inside the downstream oxygen sensor has failed (open, internal short, or high resistance)
Wiring or connector problem in the heater circuit: open, short to ground, or high resistance
Blown heater fuse or a power-supply problem to the sensor (check your service manual for the circuit)
Not usually the catalytic converter: OBD-Codes.com notes a failed converter typically sets P0420 instead

Diagnostic steps you can do

⚠ Before you start

Work on a cool engine, parked on level ground with the parking brake set. Never work under a car supported only by a jack.

Read all stored codes. If P0141 appears with other O2 heater codes (P0135, P0155, P0161) at the same time, suspect a shared fuse, relay or power feed before buying sensors.
Find the Bank 1 Sensor 2 sensor (after the catalytic converter) and inspect its wiring and connector for melted insulation, chafing on the exhaust, corrosion or a loose plug. This sensor sits low under the car, where wiring gets damaged by road debris and heat.
Check the fuse that feeds the O2 sensor heaters (see your owner's or service manual).
With a multimeter, measure the heater resistance across the sensor's heater terminals and compare it to your vehicle's specification. An open circuit means the sensor needs replacing.
With the key on, check for battery voltage at the harness side of the heater circuit.
Look for exhaust leaks ahead of the rear sensor; RepairPal lists replacing the sensor when the real problem is an exhaust leak as a common misdiagnosis.

Typical fixes

Replace the Bank 1 Sensor 2 oxygen sensor if its heater is open or shorted (an internal fault can't be repaired)
Repair damaged wiring or connectors in the heater circuit
Replace a blown fuse, and find out why it blew
Fix any exhaust leak ahead of the sensor

Repair costs vary widely by vehicle, region, parts brand and shop, so we don't quote prices. Get a written estimate after diagnosis.

🛠 When to call a pro

The code comes right back after a new sensor is fitted (OBD-Codes.com's forums have many such cases, which usually point to wiring or power supply)
The sensor is seized in the exhaust and won't come out without heat or special tools
You need circuit diagrams to trace the heater power and ground

Where to buy

Plain search links. Always match parts to your exact year, make, model and engine.

OBD2 scanners on Amazon Parts at Advance Auto Parts catalog at RockAuto

FAQs

Do I need a new catalytic converter?

Usually not. OBD-Codes.com says a failed catalytic converter typically doesn't cause P0141; a bad converter usually sets P0420. P0141 points at the downstream sensor's heater or its circuit.

What's the difference between P0135 and P0141?

Both are oxygen sensor heater faults on Bank 1. P0135 is the upstream sensor (Sensor 1, before the converter); P0141 is the downstream sensor (Sensor 2, after the converter).

Is P0141 serious?

Not usually an emergency. RepairPal rates it Moderate and says that in many cases there are no other symptoms. The sources differ a little: OBD-Codes.com mentions poor fuel economy, while RepairPal instead notes possible elevated NOx emissions and a failed emissions test.

Will replacing the sensor fix it?

Often, since a failed heater can't be repaired. But RepairPal lists replacing the sensor when the real fault is wiring, connections, an exhaust leak or the converter as common misdiagnoses, so test the heater resistance and circuit first.

Sources

Last reviewed 2026-10-22. Code definitions and repair steps can vary by manufacturer. Confirm with your vehicle's service information.