Failed heater element inside the downstream oxygen sensor; Damaged, chafed or heat-affected wiring to the sensor, often near the exhaust; Corroded, loose or contaminated connector at the sensor; Blown fuse or faulty relay supplying the heater circuit (where fitted); Exhaust leak near the sensor affecting heater or sensor behaviour; Fault in the heater driver within the engine control unit.

P0141

O2 Sensor Heater Circuit Bank 1 Sensor 2.

Generic
Powertrain
Generic code
Low severity

How this code is built

P: SystemPowertrain
0: Defined bySAE, the same on every car
1: AreaFuel and air metering
41: FaultThe specific fault in that area

What it means

P0141 means the engine control unit has found a fault in the heater circuit of the downstream oxygen sensor (Bank 1, Sensor 2), which sits after the catalytic converter. The heater brings the sensor up to working temperature quickly, and the control unit monitors its current, resistance or the time the sensor takes to become active. If these readings fall outside expected limits, the code is set.

Symptoms

Engine warning light on
Usually no noticeable change in how the car drives
Possible failed emissions test
Slightly slower sensor readiness shown on a scan tool
Other catalyst or oxygen sensor codes stored alongside it

Possible causes

Failed heater element inside the downstream oxygen sensorlikely
Damaged, chafed or heat-affected wiring to the sensor, often near the exhaustlikely
Corroded, loose or contaminated connector at the sensorlikely
Blown fuse or faulty relay supplying the heater circuit (where fitted)possible
Exhaust leak near the sensor affecting heater or sensor behaviourrare
Fault in the heater driver within the engine control unitrare

How to diagnose

Read all stored codes and freeze frame data, noting engine temperature and conditions when the code set, then check for related codes
Visually inspect the sensor wiring and connector from the sensor back along the harness, looking for melting, chafing, corrosion or water ingress
Check the exhaust around the sensor for leaks and the sensor for physical damage
Check the fuse and relay for the heater circuit using the vehicle wiring diagram, as the supply arrangement varies by model
Measure the heater element resistance at the sensor and compare it with the manufacturer's specification
With the connector disconnected, check the supply voltage and the control unit's ground or switching signal at the harness side
Check the wiring for continuity and for short circuits to ground or voltage
Clear the code and road test, then recheck with live data to confirm the heater is operating

How to fix

Replace the downstream oxygen sensor if the heater element is open circuit or out of specification
Repair or replace damaged wiring and ensure it is routed clear of hot or moving parts
Clean or replace corroded or damaged connector terminals
Replace the blown fuse or faulty relay after finding out why it failed
Repair any exhaust leak near the sensor
Diagnose and repair or replace the control unit only after wiring, supply and sensor have all been proven good

Can I keep driving?

Low severity

The car can normally be driven as the fault does not usually affect running. Book it in soon, as it may fail an emissions test and can hide other faults in the exhaust monitoring.

Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.