Faulty or contaminated Bank 2 Sensor 1 oxygen sensor (wideband or conventional, depending on the vehicle); Signal wire shorted to a voltage supply or to another circuit, or damaged wiring near the exhaust; Corroded, damaged or contaminated connector terminals at the sensor or control unit; Sensor heater circuit or power supply fault affecting the sensor's operation; Genuine rich running on Bank 2 due to leaking injector, fuel pressure fault or similar; Engine control unit fault or outdated calibration (model dependent).

P0152

O2 Sensor Circuit High Voltage Bank 2 Sensor 1.

Generic
Powertrain
Generic code
Medium severity

How this code is built

P: SystemPowertrain
0: Defined bySAE, the same on every car
1: AreaFuel and air metering
52: FaultThe specific fault in that area

What it means

P0152 means the engine control unit has seen a persistently high voltage from the upstream oxygen sensor (Bank 2, Sensor 1) circuit, beyond the range the sensor should normally produce. Bank 2 is the side of the engine that does not contain cylinder number one. The fault is set when the signal stays high or reads implausibly for longer than the control unit allows, so it cannot rely on that sensor for fuel trim control.

Symptoms

Engine management light on
Poor fuel economy
Rough idle or uneven running
Hesitation or poor performance under load
Black smoke or a strong fuel smell from the exhaust
Possible failed emissions test

Possible causes

Faulty or contaminated Bank 2 Sensor 1 oxygen sensor (wideband or conventional, depending on the vehicle)likely
Signal wire shorted to a voltage supply or to another circuit, or damaged wiring near the exhaustlikely
Corroded, damaged or contaminated connector terminals at the sensor or control unitpossible
Sensor heater circuit or power supply fault affecting the sensor's operationpossible
Genuine rich running on Bank 2 due to leaking injector, fuel pressure fault or similarpossible
Engine control unit fault or outdated calibration (model dependent)rare

How to diagnose

Read all stored and pending codes and review freeze frame data, noting engine temperature, load and fuel trim values at the time the fault set.
Confirm which side is Bank 2 and which sensor is Sensor 1 using the engine layout for that model.
Visually inspect the sensor wiring and connector for chafing, heat damage, melted insulation, water ingress and corrosion.
Check live data for the Bank 2 Sensor 1 reading and fuel trims, comparing with Bank 1, and see whether the signal is stuck high or reacts to throttle changes.
With the sensor unplugged and ignition on, check the reference and supply voltages at the harness connector against the manufacturer's data for that engine.
Test the signal and ground wires for shorts to voltage and for continuity back to the control unit.
Check for real rich conditions: fuel pressure, injector leakage, purge valve sticking open and air leaks or faults upstream, as applicable to the engine.
Check for any applicable software updates or technical bulletins for the model before condemning the control unit.

How to fix

Replace the Bank 2 Sensor 1 oxygen sensor if it is faulty, contaminated or out of specification.
Repair or replace damaged wiring, and rectify any short to voltage on the signal circuit.
Clean, repair or replace corroded or damaged connector terminals.
Correct the underlying rich condition, such as a leaking injector, fuel pressure fault or stuck purge valve.
Apply an updated control unit calibration only where the manufacturer lists it as a fix for this fault, or repair or replace the control unit if proven faulty.

Can I keep driving?

Medium severity

The car can usually be driven for a short time, but book it in soon as the control unit may run a poor fuel mixture, which wastes fuel and can eventually harm the catalytic converter. Avoid long journeys or hard driving if it runs roughly or smells of fuel.

Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.