OBD codes / P0162
P0162
ModerateO2 Sensor Circuit Malfunction (Bank 2, Sensor 3)
Low urgency. This sensor exists to watch a second catalytic converter, not to run the engine, so the car drives normally with the code set. Address it before an emissions inspection or if other exhaust codes start appearing alongside it.
What this code means
Sensor 3 is a third oxygen sensor found only on some vehicles — typically those with two catalytic converters in series on a bank, where it sits after the second converter to monitor it. If your vehicle sets this code, that position exists on your exhaust; many cars simply do not have one. P0162 is the general circuit-malfunction version for bank 2 (the cylinder bank without cylinder 1): the computer sees a signal outside the expected range but is not narrowing it to low, high, slow, or silent the way P0163 through P0166 do. Practically, the cause list is the same — a failed sensor, wiring or connector trouble along the long underbody harness run, or an exhaust leak near the sensor. Because this sensor is purely an emissions monitor far downstream, drivability is almost never affected.
Symptoms you might notice
- Check-engine light with no change in driving feel
- Failed emissions test while the code is active
- Usually no other symptoms
What it costs to fix
Typical range: $100–$450 · about ~0.3–1.5 hrs of labor
| If the cause is… | Part | Labor |
|---|---|---|
| O2 sensor (Bank 2, Sensor 3) | $30–$200 | ~0.3–1 hrs |
| Wiring or connector repair | $5–$60 | ~0.5–1.5 hrs |
| Exhaust leak repair (gasket or flange) | $15–$100 | ~0.5–1.5 hrs |
Sensor 3 sits far back under the vehicle, which usually means easy wrench access but a long, exposed wiring run — so wiring damage is a bit more common here than at other positions, and rust can make the sensor itself stubborn to remove.
The price swings on which cause it turns out to be — so confirm the cause before paying. Diagnose P0162 for my exact vehicle →
Frequently asked
My car has a Sensor 3? What is that?
Some exhaust systems run two catalytic converters in a row on each bank, and Sensor 3 sits after the second one to confirm it is doing its share. Only vehicles built that way have this sensor — the code appearing on your car means yours is one of them.
Is P0162 serious?
Not for driving — it is an emissions-monitoring fault, not an engine-control fault. The engine computer fuels the engine using the upstream sensors, which are unaffected. It mainly matters for inspection compliance and for keeping tabs on converter health.
Why is my code a general malfunction instead of a specific one?
P0162 is the catch-all for that sensor's circuit when the fault does not match a tighter definition like low voltage (P0163) or no activity (P0166). Erratic or intermittent signals — often from a corroded connector or failing sensor element — tend to land here.
Should I replace all my O2 sensors at once?
Not necessarily. Diagnose this circuit first — if wiring is the fault, a new sensor fixes nothing. On a high-mileage vehicle where a sensor has genuinely failed with age, replacing its same-age partners can be reasonable preventive maintenance, but it is optional, not required.
Seeing P0162 on your car? Get a diagnosis specific to your exact year, make and model.
Diagnose P0162 for my vehicleRelated trouble codes
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Generic OBD-II reference. Manufacturer-specific behavior varies — confirm with a scan tool and, for safety-related codes, a professional inspection.