Failed heater element inside the Bank 2 Sensor 3 oxygen sensor (open circuit or out-of-range resistance); Damaged, chafed or corroded wiring to the sensor heater, including shorts to earth or to supply; Corroded, loose or contaminated connector at the sensor or in the harness; Blown fuse or faulty relay supplying the heater circuit, where fitted; Exhaust heat or road damage to the sensor lead near the exhaust; Fault in the engine control unit heater driver.

P0167

O2 Sensor Heater Circuit Bank 2 Sensor 3.

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
67: FaultThe specific fault in that area

What it means

P0167 means the engine control unit has found a fault in the heater circuit of the oxygen sensor fitted at Bank 2, Sensor 3. This is usually a third sensor further along the exhaust, after the catalytic converter. The unit checks the heater's current draw, resistance or driver feedback, and sets the code when these are outside limits, for example an open circuit, a short or a failed heater element. Whether the car has this sensor, and where it sits, depends on the model and engine.

Symptoms

Engine warning light on
Usually no noticeable change in driving
Possible failed emissions or MOT test
Other oxygen sensor or catalyst monitor codes stored alongside it
Slightly slower sensor readiness, so some monitors may not complete

Possible causes

Failed heater element inside the Bank 2 Sensor 3 oxygen sensor (open circuit or out-of-range resistance)likely
Damaged, chafed or corroded wiring to the sensor heater, including shorts to earth or to supplylikely
Corroded, loose or contaminated connector at the sensor or in the harnesspossible
Blown fuse or faulty relay supplying the heater circuit, where fittedpossible
Exhaust heat or road damage to the sensor lead near the exhaustpossible
Fault in the engine control unit heater driverrare

How to diagnose

Read all stored and pending codes and the freeze frame data, and note whether other heater or oxygen sensor codes are present for other sensors
Confirm which sensor is Bank 2 Sensor 3 on this model, using the manufacturer's exhaust layout, as bank numbering and sensor positions vary by engine
Visually inspect the sensor lead, harness routing and connector for heat damage, chafing, water ingress and corrosion
Check the relevant fuse and relay, where the circuit has them, using the wiring diagram
Measure the sensor heater resistance at the sensor connector and compare it with the manufacturer's specification
With the connector disconnected, check the heater supply voltage and the control or earth signal from the engine control unit
Check the wiring for continuity and for shorts to earth or supply between the sensor connector and the control unit
Clear the code, run the car through a drive cycle and recheck that it does not return

How to fix

Repair or replace damaged wiring and secure the harness away from hot or moving parts
Clean or replace a corroded or damaged connector and its terminals
Replace a blown fuse or faulty relay, after finding out why it failed
Replace the Bank 2 Sensor 3 oxygen sensor if the heater resistance is out of specification
Replace or repair the engine control unit only after the wiring and sensor have been fully proven good

Can I keep driving?

Low severity

The car can normally be driven while you arrange a repair, as this fault rarely affects how it runs. Get it checked soon, because it may cause an emissions test failure and could hide other developing faults.

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