Failed downstream oxygen sensor on bank 2 (sensor 2), the most common cause; Open or shorted wiring in the sensor circuit, including damaged connectors or chafed harness; Blown fuse that supplies heater power to the oxygen sensor circuit; Exhaust leak before the sensor that lets outside air skew the reading; Contaminated sensor from coolant or oil burning in the exhaust; PCM driver circuit fault for the oxygen sensor heater or signal return

DTC codes / P01xx · Fuel and air metering / P0160

P0160O2 Sensor Circuit No Activity (Bank 2 Sensor 2)

Q: What does code P0160 mean?

O2 Sensor Circuit No Activity (Bank 2 Sensor 2). P0160 means the powertrain control module (PCM) has not seen any meaningful voltage activity from the downstream oxygen sensor on bank 2, which is the side of the engine that does not contain cylinder number one. The sensor is supposed to switch between lean and rich voltage readings as the exhaust passes it, and the PCM sets this code when that signal stays flat or absent for too long.

P0160 means the powertrain control module (PCM) has not seen any meaningful voltage activity from the downstream oxygen sensor on bank 2, which is the side of the engine that does not contain cylinder number one. The sensor is supposed to switch between lean and rich voltage readings as the exhaust passes it, and the PCM sets this code when that signal stays flat or absent for too long.

SystemPowertrain

Code typeGeneric (all makes)

SeverityLow

Fix difficultyIntermediate

AreaFuel and air metering

Symptoms you may notice

Illumination of the check engine light, often with no other noticeable symptoms
A slight drop in fuel economy because the PCM may default to a richer fuel mixture
Occasional rough idle or hesitation when the engine is cold
A failed emissions test due to the oxygen sensor monitor not completing
In rare cases, a sulfur or rotten-egg smell from the exhaust if the mixture stays rich

Common causes, most likely first

Failed downstream oxygen sensor on bank 2 (sensor 2), the most common cause
Open or shorted wiring in the sensor circuit, including damaged connectors or chafed harness
Blown fuse that supplies heater power to the oxygen sensor circuit
Exhaust leak before the sensor that lets outside air skew the reading
Contaminated sensor from coolant or oil burning in the exhaust
PCM driver circuit fault for the oxygen sensor heater or signal return

How to diagnose and fix it

Scan all modules and record freeze-frame data to confirm the code is current and not history
Inspect the bank 2 sensor 2 wiring harness and connector for damage, corrosion, or loose pins
Check the oxygen sensor heater fuse and verify battery voltage at the sensor connector with the key on
Measure the sensor signal voltage with a scan tool or multimeter while revving the engine to see if it switches
Perform a smoke test on the exhaust system to rule out leaks upstream of the sensor
Replace the bank 2 sensor 2 oxygen sensor if wiring and power checks pass but the signal stays flat
Clear the code and complete a drive cycle to verify the repair and confirm the monitor runs

Why a lazy sensor mimics a dead one

A downstream oxygen sensor can be slow to respond without being completely dead, and the PCM may still set P0160 if the activity is too weak to satisfy its test.
Exhaust leaks between the engine and the sensor are a commonly missed cause because they pull in outside oxygen and make the sensor read lean when the mixture is actually fine.
Some vehicles use the downstream sensor mainly to monitor catalytic converter efficiency, so a P0160 can appear with no driveability complaint at all.
Replacing the sensor without checking the heater circuit fuse and wiring often leads to a repeat code because the new sensor never gets power.
A contaminated sensor from a failing head gasket or excessive oil consumption will fail again quickly unless the root cause is repaired first.

Can I keep driving with P0160?

The vehicle is generally safe to drive with P0160 because the PCM falls back to default fuel control, but avoid long trips and heavy loads until it is repaired. Do not ignore it indefinitely, since a rich default mixture can eventually damage the catalytic converter and increase emissions.

Tools that help

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Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.