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P0161: Oxygen sensor heater (bank 2, sensor 2): circuit fault

The heater in the bank 2 oxygen sensor after the catalytic converter has a fault. Usually a blown fuse, the connector or the sensor itself.

Code P0161 at a glance
CodeP0161
SystemEngine and transmission
GroupP01xx, Air and fuel metering
TypeGeneric: it means the same on every make
Can you keep driving?Yes, no rush

What P0161 means

The oxygen sensor after the catalytic converter is mainly there to check that the converter is cleaning the exhaust properly; it has little effect on how the engine runs. The sensor only works when it is very hot, so it has a small built-in heater that warms it up after a cold start. This code means the heater circuit has a fault. Bank 2 is the side of the engine opposite cylinder 1, and it only exists on V-shaped or boxer engines.

Most common causes

  • Blown fuse for the oxygen sensor heaters
  • Sensor connector loose or corroded
  • Broken supply or earth wire to the heater
  • Burnt-out heater element inside the sensor (the most common cause; the sensor has to be replaced)
  • Faulty relay or ECU supply to the heater

Symptoms

  • Engine warning light on
  • The car drives normally
  • Some of the ECU’s emissions self-tests never complete

Can you drive with P0161?

Yes, no rush You can keep using the car normally. Fix it when convenient, but before the next inspection, as a lit warning light means a fail.

How to check it

Look in the handbook for the fuse that feeds the oxygen sensor heaters and check it. If it is fine, a garage can measure the heater resistance at the sensor connector: with no continuity, the sensor needs replacing.

How to read and clear P0161 with Final OBD

Plug an OBD2 scanner in under the steering wheel, switch the ignition on and open Final OBD. Under Faults you’ll see P0161 with this same explanation and whether it’s confirmed, pending or permanent.

With Free you read this code with its short description for nothing, and clear it if the engine stores it over standard OBD. With Pro you get the full explanation, how the car was running when it was logged (revs, temperature, load) and clearing in every control unit.

Clearing the code only turns the light off: if the cause is still there, it comes back. Clear it once it’s fixed, and not right before the ITV. It’s all in how to read and clear fault codes and in the ITV and OBD.

Similar codes

P0161 is a generic code, so it means the same on any make, for example on Abarth, Citroën, Hyundai, Mini, Seat, Volvo. See what Final OBD does on your car in makes and models.

What does code P0161 mean?

The oxygen sensor after the catalytic converter is mainly there to check that the converter is cleaning the exhaust properly; it has little effect on how the engine runs. The sensor only works when it is very hot, so it has a small built-in heater that warms it up after a cold start. This code means the heater circuit has a fault. Bank 2 is the side of the engine opposite cylinder 1, and it only exists on V-shaped or boxer engines.

Can you drive with P0161?

You can keep using the car normally. Fix it when convenient, but before the next inspection, as a lit warning light means a fail.

How do you clear P0161?

With an OBD2 scanner and an app like Final OBD, which clears it for free if it’s stored by the engine control unit. But clearing it only turns the light off: if the cause isn’t fixed, P0161 comes back.