O2 Sensor Circuit No Activity Detected (Bank 2 Sensor 2)
What it means
The engine computer has found that the bank 2 downstream oxygen sensor signal stays flat after warm-up, even during acceleration and fuel cut. This usually means an open circuit, a heater that is not working or a completely failed sensor; engine performance is normally unaffected.
Symptoms4
- Check engine light on.
- Engine usually runs normally.
- A heater code such as P0161 or P0056 may appear with it.
- Failed emissions test.
Possible causes5
- Disconnected connector or broken wire under the car.
- Faulty sensor heater or its fuse.
- Completely failed sensor.
- Terminals corroded by water.
- Engine computer fault (rare).
How to diagnose5
- Fix any heater codes first.
- Watch the sensor signal during acceleration and when lifting off, and compare it with the bank 1 downstream sensor.
- Check the connector under the car is tight and plugged into the right sensor.
- Check wiring continuity using the manufacturer wiring diagram.
- If the circuit and heater are fine, replace the sensor.
How to fix5
- Reconnect or clean the connector.
- Repair the broken wire and secure it in its clips.
- Repair the heater circuit, or replace the fuse after finding why it blew.
- Replace the bank 2 downstream oxygen sensor if it is proven failed.
- Clear the codes and drive until the sensor test completes.
Repair cost
In Saudi riyals; the highlighted part is the expected range for this fault.
Reconnecting a connector or repairing a wire is cheap, while a new sensor takes the cost to the upper end.
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
The code appeared after exhaust work. Why?
Most likely the connector was left unplugged or the wire was damaged during the job, so check it before anything else.
How is this different from P0156?
P0156 is a general circuit fault, while P0160 specifically means the signal is flat and not moving, which points to an open circuit or an unheated sensor.
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.
Report a mistake
Spotted something inaccurate? Tell us and we will review and correct it.
Report received — thank you
This is your private tracking link. It shows the status and our reply as soon as it is posted.
The link is saved in this browser only.