What Does P0160 Mean?
The downstream oxygen sensor on bank 2 (sensor 2) is not switching between rich and lean as expected. The ECM has detected that the sensor voltage remains fixed or shows no meaningful activity over a defined monitoring period. This post-catalytic converter sensor is primarily used to monitor catalytic converter efficiency. The driver may notice a check engine light and potentially reduced fuel economy.
Common Causes
40%
Failed or contaminated downstream O2 sensor producing a flat-line signal
25%
Damaged or corroded wiring/connector in the O2 sensor circuit
15%
Exhaust leak near the downstream sensor location altering readings
12%
Catalytic converter failure causing abnormal exhaust composition at the sensor
8%
ECM ground circuit fault or internal ECM issue affecting sensor reading
Diagnostic Steps
1
Monitor bank 2 sensor 2 live data voltage — it should show a relatively steady signal between 0.5–0.8V when the catalyst is working properly. A completely flat line at 0V or 0.45V indicates sensor failure.
2
Inspect the O2 sensor wiring harness and connector at bank 2 sensor 2 for corrosion, chafing, melted insulation, or rodent damage. Repair any visible damage.
3
Backprobe the sensor signal wire and check voltage with a multimeter (key on, engine running). Compare to the scan tool reading to rule out a wiring issue between sensor and ECM.
4
Check the sensor heater circuit — measure resistance across the heater pins (typically 4–15 ohms). An open heater can prevent the sensor from reaching operating temperature.
5
Verify there are no exhaust leaks upstream of the sensor by performing a visual and audible inspection of the exhaust manifold, catalytic converter connections, and downstream pipe joints.
Estimated Repair Cost
$150 - $400
Parts + labor, varies by vehicle and location
The downstream oxygen sensor on bank 2 (sensor 2) is not switching between rich and lean as expected. The ECM has detected that the sensor voltage remains fixed or shows no meaningful activity over a defined monitoring period. This post-catalytic converter sensor is primarily used to monitor catalyt...
The most common cause of P0160 (02 Sensor Circuit No Activity Detected (Bank 2 Sensor 2)) is: Failed or contaminated downstream O2 sensor producing a flat-line signal
Typical repair costs for P0160 range from $150 to $400, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Generally safe to continue driving short distances. The vehicle will not be able to accurately monitor catalytic converter efficiency, which may mask a converter problem. Fuel economy may suffer slightly and the vehicle will fail an emissions test.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P0160 to identify the root cause.
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Quick Info
Category
Powertrain
System
Fuel System / Emissions
Difficulty
Type
Generic (SAE)
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