P0160
O2 Sensor Circuit No Activity Detected (Bank 2 Sensor 2)P0160 is a generic OBD-II powertrain diagnostic trouble code: O2 Sensor Circuit No Activity Detected (Bank 2 Sensor 2). It is logged by the engine control unit when the o2/lambda monitor detects that a specific fault threshold has been exceeded — typically resulting in the malfunction-indicator lamp (MIL / check-engine light) being illuminated.
What P0160 means
P0160 is set when the engine control module (ECM) determines that the downstream oxygen sensor on Bank 2, Sensor 2 has produced no measurable voltage activity for a period that exceeds the manufacturer-defined threshold. Unlike P0156, which flags an out-of-range signal, P0160 specifically means the sensor output is completely flat — the ECM sees no fluctuation at all, suggesting a dead sensor, open circuit, or total heater failure that prevents the sensor from reaching operational temperature.
Under normal conditions, a functioning downstream O2 sensor produces a slowly varying signal as the exhaust chemistry changes. Even a well-functioning catalytic converter allows minor oscillations that the ECM can detect. When the ECM observes an absolutely static voltage — typically around 0.45 V — for longer than the allowed window, it concludes that the sensor has ceased to operate and logs P0160.
The most common cause is an aged or contaminated oxygen sensor that has lost its electrochemical activity. However, an open circuit in the signal wire (due to heat-damaged insulation or a broken connector pin) or a failed heater element (which keeps the sensor at 600–850 °C for fast light-off) will produce the same symptom. Exhaust leaks near the sensor can introduce ambient oxygen and artificially flatten the reading on some designs.
Because P0160 disables catalyst efficiency monitoring for Bank 2, the vehicle may fail emissions testing even if the catalyst is healthy. It is important not to confuse this code with P0420 (catalyst efficiency below threshold); P0160 must be resolved first before catalyst efficiency can be accurately evaluated.
Common causes
Most-frequently reported root causes when P0160 is logged.
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1
Failed or internally dead Bank 2 Sensor 2 oxygen sensor
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2
Open circuit in the sensor signal wire
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3
Failed sensor heater element (sensor never reaches operating temperature)
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4
Corroded or damaged sensor connector or terminal pins
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5
Exhaust leak near the sensor introducing excess ambient oxygen
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6
Short to voltage on the signal circuit (flatlines the reading)
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7
Contaminated sensor element (oil, coolant, silicone fouling)
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8
Faulty ECM signal input circuit
Symptoms drivers notice
How to diagnose P0160
A typical diagnostic flow when this code is present.
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1
Retrieve and record all stored codes and freeze-frame data with a scan tool
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2
Inspect the Bank 2 Sensor 2 wiring harness and connector for open circuits, corrosion, melted insulation, or broken pins
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3
With ignition on and engine off (KOEO), verify battery voltage is present on the heater supply wire and a solid ground on the heater return wire
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4
Measure heater element resistance across the heater pins (disconnect sensor first); compare against specification — an open reading (OL) indicates a blown heater
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5
Start the engine and let it reach operating temperature; monitor live sensor voltage — a completely flat line at ~0.45 V confirms no activity
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6
Check for exhaust leaks upstream of and around the sensor bung with a smoke test or visual inspection
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7
If heater and wiring check out, replace the Bank 2 Sensor 2 oxygen sensor
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8
Clear codes and perform a full drive cycle to confirm the repair
Related powertrain codes
- P0040 — Upstream Oxygen Sensors Swapped From Bank To Bank
- P0041 — Downstream Oxygen Sensors Swapped From Bank To Bank
- P0130 — O2 Sensor Circuit Malfunction (Bank 1 Sensor 1)
- P0131 — O2 Sensor Circuit Low Voltage (Bank 1 Sensor I)
- P0132 — O2 Sensor Circuit High Voltage (Bank 1 Sensor 1)
- P0133 — O2 Sensor Circuit Slow Response (Bank 1 Sensor 1)
Frequently asked questions
Is P0160 worse than P0156?
P0160 (no activity) is generally considered more severe than P0156 (out-of-range signal) because it indicates the sensor has stopped producing any output at all, rather than just an incorrect reading. This makes diagnosis slightly simpler but usually points to a failed sensor or open circuit.
Can a blown heater fuse cause P0160?
Yes. If the fuse protecting the O2 sensor heater circuit has blown, the sensor may never reach operating temperature, resulting in a flat, inactive signal. Always check the relevant fuse and relay before replacing the sensor.
Will replacing the O2 sensor definitely fix P0160?
Not always. If the wiring harness is damaged or the connector is corroded, a new sensor will exhibit the same fault. Diagnose the circuit first — confirm heater power/ground and signal wire continuity — before purchasing a replacement sensor.
Could P0160 and P0420 appear together?
Yes, and the order matters. P0160 disables the downstream monitoring used to evaluate catalyst efficiency, so a simultaneously stored P0420 may be a false trigger caused by the dead sensor. Always resolve P0160 first and retest for P0420 afterwards.
How long does it take for P0160 to set after a sensor fails?
Most ECMs require the sensor to show no activity for approximately 90–180 seconds of closed-loop operation at normal operating temperature before setting the code. A fully dead sensor will usually trigger the MIL within one or two drive cycles.
Disabling P0160 in software
RaceTune can permanently disable P0160 — and any other OBD-II diagnostic trouble code — on every ECU family we support. The monitor is disabled inside the ECU itself, so the fault stops being logged: the warning light stays off and the engine never enters limp mode for this code. The change is tied to your exact software version.
Software modifications affect emissions compliance and are not road-legal in many jurisdictions. RaceTune service files are intended for motorsport, off-road, and export use.
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