P0161

O2 Sensor Heater Circuit (Bank 2 Sensor 2)

Car Fault Codes Emissions & exhaust

Can you still drive? Yes, normally

Who can fix it? DIY with some experience

Typical repair time 30 minutes – 1.5 hours

Typical cost SAR 100 to 900

What it means

The engine computer has found a fault in the heater of the bank 2 downstream oxygen sensor, which monitors that bank's catalytic converter. The fault rarely affects how the engine runs, but the sensor does not warm up fast enough, so converter monitoring stops.

Symptoms4

Check engine light on, usually with no other symptoms.
Bank 2 catalytic converter self-test does not complete.
A no-activity code such as P0160 may appear with it.
Failed emissions test.

Possible causes5

Burned-out heater element inside the downstream sensor.
Damaged wiring or connector under the car.
Blown heater fuse.
Connector terminals corroded by water.
Fault in the control circuit inside the engine computer (rare).

How to diagnose5

Check the heater fuse and look for other heater codes.
Unplug the bank 2 downstream sensor and measure heater resistance, comparing it with the manufacturer specification or the bank 1 downstream sensor.
Check supply voltage at the connector with the ignition on.
Inspect the connector under the car for water or corrosion.
Check the control wire to the computer for an open.

How to fix4

Clean the connector or repair the wiring.
Replace a blown fuse after finding why it blew.
Replace the bank 2 downstream oxygen sensor if the heater is open.
Clear the codes, start from cold, and drive to confirm the code does not return.

Repair cost

0–500

500–2,000

2,000–5,000

5,000+

In Saudi riyals; the highlighted part is the expected range for this fault.

A connector or fuse repair is cheap, while a new sensor takes the cost to the upper end, especially if it is rusted in.

Prices are rough estimates for common cars at independent workshops and vary with the car and the source of the part.
Prices last updated: September 2026

Frequently asked questions

Can I compare it with the bank 1 sensor?

Yes. If both sensors are the same type, their heater resistance should be similar, which helps you decide quickly.

Does this fault affect fuel consumption?

Usually not, because the downstream sensor monitors the converter and has little control over the mixture.

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This guide is for information only and does not replace an inspection by a qualified technician. If the fault involves brakes, steering, engine temperature, electrics or refrigerant, do not attempt the repair yourself.

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