The P01570 code corresponds to:

“O2 Sensor Circuit Low Voltage (Bank 2, Sensor 2)”

Here’s a clear breakdown:

1. What It Means

O2 Sensor: Oxygen sensors monitor the level of oxygen in the exhaust to help the engine run efficiently.

Bank 2, Sensor 2:

Bank 2 → The side of the engine opposite cylinder 1.
Sensor 2 → The downstream O2 sensor, located after the catalytic converter.

Low Voltage: The sensor is reading less voltage than expected, indicating a lean condition or possible sensor/electrical issue.

2. Common Causes

1. Faulty O2 Sensor (most common for P01570)

2. Wiring Issues

Frayed or damaged sensor wires

Corrosion at the connector

3. Exhaust Leaks

Before the sensor (can introduce extra oxygen and lower voltage

4. Catalytic Converter Problems

A clogged or damaged converter can affect downstream sensor readings

5. ECU Issues (rare)

The engine control module may misread the sensor

3. Diagnostic Steps

1. Visual Inspection

Check sensor connector, wiring, and exhaust around the sensor for leaks or damage.

2. Check Voltage with a Multimeter

Bank 2 Sensor 2 should fluctuate around 0.1–0.9V under normal operation.

A consistently low voltage (<0.1V) confirms the code.

3. Check Fuel Trim

Use a scan tool to see if the ECU is adding fuel excessively (possible lean condition).

4. Test O2 Sensor Heater Circuit

Many sensors have a built-in heater; if this fails, sensor voltage can be abnormal.

5. Swap / Replace Sensor

If all wiring checks out and voltage is still low, replace the sensor.

4. Fix / Repair

If sensor is bad → Replace the Bank 2, Sensor 2 O2 sensor.

If wiring is damaged → Repair or replace harness.

If exhaust leak is present → Fix the leak before replacing the sensor.

If catalytic converter is faulty → Replace the converter (less common).

💡 Tip for your service shop:
Many downstream O2 sensors fail after catalytic converter replacement, so always check the sensor’s voltage with a scan tool before replacing it blindly. Sometimes cleaning the connector or repairing wiring solves it.

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