P0141 on a Ford
P0141 says the heater inside the bank 1, sensor 2 oxygen sensor - the one after the catalytic converter - is not drawing current the way the computer expects. The heater exists to get the sensor reading quickly on cold starts; without it the sensor still works once the exhaust warms it, which is why the truck drives normally with the light on.
On Fords the usual outcome is the sensor itself, but the heater circuit shares a fuse with other things on many models - so the five-minute fuse check comes before the hundred-dollar sensor.
- Failed heater element inside the sensor: The most common outcome. Heaters fail from age and heat cycles; the sensing element can be fine while the heater is open-circuit.
- Blown fuse feeding the heater circuit: Check the fuse box diagram for the HO2S heater fuse before buying anything. If it blows again after replacement, there is a short to find - often chafed wiring near the exhaust.
- Damaged wiring or connector: The downstream sensor pigtail lives in a hot, exposed spot under the truck. Look for melted insulation or a connector that has been dragged.
- Corroded ground: The heater needs a good ground path; corrosion at the connector or chassis ground shows up as this code on higher-mileage trucks.
Full P0141 guide for any vehicle