Can a bad O2 sensor cause a rich condition?

No, not with P0152. A sensor that reads falsely high makes the engine computer think bank 2 is rich, so it takes fuel away and the bank can actually run lean, not rich. A real rich condition usually comes from the fuel side, such as a leaking injector or high fuel pressure. Fuel trims tell you which it is: strongly negative trims point to a real rich mixture.

Is P0152 the same as P0132?

It is the same fault on the other bank. P0132 is high voltage from the upstream sensor on bank 1, the bank with cylinder 1, and P0152 is high voltage from the upstream sensor on bank 2. If both appear together, look for a shared cause such as fuel pressure or a harness fault.

Can I drive with P0152?

For a short time, yes, but a rich mixture wastes fuel and can overheat the catalytic converter, which is much more expensive to replace than a sensor. Have it diagnosed within days. Stop driving if the check engine light flashes or you smell raw fuel.

Which sensor is Bank 2 Sensor 1?

It is the upstream oxygen sensor, the one before the catalytic converter, on the half of the engine that does not contain cylinder 1. Most V6, V8 and flat-six (boxer) engines have two cylinder banks, each with its own upstream sensor. A few inline-sixes with two exhaust manifolds, such as BMW's M54, also split into bank 1 (cylinders 1-3) and bank 2 (cylinders 4-6). Which physical side is bank 2 differs between makers, so check the service information for your engine before you order a part.

P0152: O2 Sensor Circuit High Voltage (Bank 2, Sensor 1)

Quick Answer

Safe to drive (short-term)

P0152 means the upstream oxygen sensor on bank 2 has reported a high voltage for too long, which reads as a rich mixture with too little oxygen in the exhaust. Bank 2 is the half of a V6, V8 or flat-six engine that does not contain cylinder 1 (a few inline-sixes with a split exhaust, such as BMW's M54, also have one). It is the same fault as P0132 on the other bank. The cause is either a real rich condition on that bank or a sensor or wiring fault, such as a signal wire shorted to voltage.

Severity: Moderate · Emissions
Estimated repair cost: From €65 to €650+, varies by vehicle

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What does P0152 mean?

P0152 is a emissions-related diagnostic trouble code classified as moderate severity. When your vehicle's ECU detects this condition, it stores P0152 and illuminates the check engine light.

Where it is on the car

Engine
Oxygen sensor before the converter (sensor 1)
Catalytic converter
Oxygen sensor after the converter (sensor 2, or 3 on some cars)
Silencer and tailpipe

This code is for bank 2. V6, V8 and flat engines have two cylinder banks, each with its own converter and sensors; bank 2 is the side without cylinder 1.

What are the symptoms of P0152?

If your vehicle has triggered P0152, you may notice one or more of these symptoms:

Check engine light on
Noticeably higher fuel consumption
Smell of fuel or a sulphur smell from the exhaust
Black smoke or sooty tailpipe
Rough idle or misfire in severe cases
Failed emissions test with high CO or HC

What causes P0152?

Here are the most common causes of P0152:

Failed upstream O2 sensor on bank 2 stuck at high voltage
: high
Real rich condition on bank 2 (leaking injector, high fuel pressure)
: medium
Signal wire shorted to a voltage source in the harness
: medium
Sensor contaminated by coolant, oil or silicone sealant
: medium
Fuel in the engine oil from short trips, fed back through the crankcase ventilation
: low
Engine computer fault
: low

Is it safe to drive with P0152?

Generally yes, for short-term driving. You can drive to a workshop, but have it checked within days. A genuinely rich mixture on bank 2 wastes fuel and can overheat and clog the catalytic converter. If you smell raw fuel, see black smoke, or the check engine light flashes, stop driving.

How do you diagnose P0152?

Follow these steps to pinpoint the root cause of P0152:

Read all stored codes and freeze frame data. P0175 (System Too Rich, Bank 2) alongside P0152 supports a real rich condition on bank 2. Misfire codes on bank 2 cylinders need attention first
Warm the engine and compare Bank 2 Sensor 1 with Bank 1 Sensor 1 on live data. A narrowband sensor pinned near or above 0.9 volts while the bank 1 sensor keeps switching points at bank 2
Check the bank 2 fuel trims. Strongly negative trims on bank 2 only mean the engine computer is taking fuel away from that bank, which supports a real rich condition rather than a sensor fault
Unplug the bank 2 sensor with the key on and watch the reading. If it still shows high voltage with the sensor disconnected, the signal wire is shorted to voltage in the harness
Inspect the harness for chafing or melting where the sensor wiring runs near other circuits, and check the connector for water or corrosion
If the sensor looks white, glazed or oily when removed, find the source of the contamination (coolant leak, oil burning) before fitting a new one
Replace the sensor if the wiring and fuel system test good, clear the code and confirm it stays off after a drive cycle

How much does P0152 cost to fix?

Repair costs for P0152 vary depending on the root cause and your vehicle. Here are typical estimates:

Repair	Parts Cost	Labor Cost	Total Estimate	DIY Difficulty
Replace upstream O2 sensor (Bank 2, Sensor 1)	€40–€180	€50–€140	€90–€320	Moderate
Repair shorted O2 sensor wiring	€5–€30	€60–€150	€65–€180	Moderate
Diagnose and fix rich condition (injector, fuel pressure)	€30–€400	€80–€250	€110–€650	Professional
Replace upstream O2 sensors on both banks at once	€80–€360	€80–€200	€160–€560	Moderate

Prices estimated as of March 2026. Costs vary by region, vehicle, and shop.

Full repair guides

Oxygen Sensor Replacement Cost

P0152 on specific vehicles

P0152 behaves differently depending on your vehicle. Select your car below for model-specific causes and known issues:

P0152 on Mercedes-Benz

Mercedes-Benz C-Class (V6)

See Mercedes-Benz-specific causes & cost

P0152 on BMW

BMW 5 Series (545i/540i/550i) · BMW 3 Series (E46 325i/330i)

See BMW-specific causes & cost

These codes are often seen alongside P0152 or indicate related issues:

Common questions about P0152

What does P0152 mean?: P0152 means the upstream oxygen sensor on bank 2 has read high voltage for longer than the engine computer allows. High voltage means little oxygen in the exhaust, which reads as a rich mixture. Either that bank really is running rich, or the sensor or its wiring is giving a false high signal.
Can a bad O2 sensor cause a rich condition?: No, not with P0152. A sensor that reads falsely high makes the engine computer think bank 2 is rich, so it takes fuel away and the bank can actually run lean, not rich. A real rich condition usually comes from the fuel side, such as a leaking injector or high fuel pressure. Fuel trims tell you which it is: strongly negative trims point to a real rich mixture.
Is P0152 the same as P0132?: It is the same fault on the other bank. P0132 is high voltage from the upstream sensor on bank 1, the bank with cylinder 1, and P0152 is high voltage from the upstream sensor on bank 2. If both appear together, look for a shared cause such as fuel pressure or a harness fault.
Can I drive with P0152?: For a short time, yes, but a rich mixture wastes fuel and can overheat the catalytic converter, which is much more expensive to replace than a sensor. Have it diagnosed within days. Stop driving if the check engine light flashes or you smell raw fuel.
Which sensor is Bank 2 Sensor 1?: It is the upstream oxygen sensor, the one before the catalytic converter, on the half of the engine that does not contain cylinder 1. Most V6, V8 and flat-six (boxer) engines have two cylinder banks, each with its own upstream sensor. A few inline-sixes with two exhaust manifolds, such as BMW's M54, also split into bank 1 (cylinders 1-3) and bank 2 (cylinders 4-6). Which physical side is bank 2 differs between makers, so check the service information for your engine before you order a part.

Read our detailed guides

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