P0141Fuel and air

P0141: O2 Sensor Heater Circuit Malfunction (Bank 1, Sensor 2)

P0141 means the car's computer found a problem with the heater inside the downstream oxygen sensor on bank 1, the side of the engine with cylinder 1. The car usually drives normally, but the check engine light stays on, and the code can cause an emissions test failure until it is fixed.

You can keep driving

The data lists no limp mode for this code, so the car normally runs as usual. Fix it soon, because the check engine light stays on, emissions monitors cannot complete, and related codes can follow.

What it means

The downstream oxygen sensor (sensor 2) sits after the catalytic converter and helps the computer judge whether the converter is working. It has a built-in electric heater so it reaches working temperature quickly. The engine computer switches this heater on and off and checks the voltage on the heater circuit and the current flowing through it. If the current is too low or too high, or the voltage does not match what the computer commanded, it sets P0141. Without a working heater the sensor signal is unreliable, so the computer suspends the converter monitor and fuel trim adjustments that depend on that sensor. Limits vary by manufacturer. GM, for example, fails the circuit outside 0.3 to 2.5 amps and needs two trips, and Ford uses P0141 as its general heater circuit code. The light often comes on only after two drive cycles.

Likely causes

Burnt-out heater element in the oxygen sensorVery likely
This is the most common cause, and the fix is to replace the sensor.
Open heater supply (fuse or relay) or open control wirePossible
If power or the control signal cannot reach the heater, no current flows and the computer sees a fault.
Short in the heaterPossible
A short lets too much current flow, which pushes the reading above the allowed limit.
Corroded connectorLess likely
Corrosion adds resistance at the plug and reduces heater current.

What you may notice

Check engine light on, usually after two drive cycles
Catalyst monitor readiness not set, which matters for emissions tests
Follow-up codes such as P0140 or P0136 may appear

What to check, cheapest first

1Read the code with a scan tool and note any other stored codes, such as P0140, P0136 or the related P0036 to P0038. · you can do it
2Check the fuse and relay that supply the oxygen sensor heater, using the fuse diagram in the owner's manual. · you can do it
3Inspect the sensor's wiring and connector for damage, melted insulation, moisture or corrosion. · you can do it
4Measure the heater element resistance at the sensor and compare it with the specification for your vehicle. · mechanic
5Check for supply voltage and a working ground-side control signal at the connector while the computer commands the heater on. · mechanic
6Replace the downstream sensor if the heater element is open or shorted, clear the code, and complete a drive cycle to confirm the fix. · mechanic

Frequently asked questions

Can I drive with a P0141 code?+

Usually yes, since limp mode is not expected. Repair it soon so the light does not hide other problems and the emissions monitors can finish.

Can a loose gas cap cause P0141?+

No. A gas cap affects the fuel vapor system, not the oxygen sensor heater circuit. Check the sensor, fuse, relay and wiring instead.

Will P0141 pass an emissions test?+

Probably not. The check engine light is on and the catalyst monitor may not be ready, and either can cause a failure.

Can I fix it myself?+

Often yes. The repair is rated easy, at roughly 0.3 to 1.5 hours, and usually means replacing the sensor or fixing a fuse or wiring fault.

Written with the help of AI from the public OBDex definition (CC0). Each make may use the code differently. Updated: 2026-11-10