O2 Sensor Circuit High Voltage (Bank 2, Sensor 1)
The P0152 code means the vehicle's onboard diagnostic system has detected: O2 Sensor Circuit High Voltage (Bank 2, Sensor 1). This is a serious severity code.
- Keep driving?
- Yes, but fix soon
- DIY difficulty
- easy
- Estimated cost
- $50-$200
Test O2 sensor voltage (should fluctuate 0.1-0.9V). Do not replace a $150 sensor without confirming it is actually bad first.
Shows real-time O2 sensor readings on your phone. See if the sensor is lazy, stuck, or actually working before spending money.
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Common Symptoms
- Check Engine Light on
- Rich running on Bank 2
- Poor fuel economy
- Possible black smoke
Probable Causes (Ranked by Likelihood)
- Stuck-rich upstream O2 sensor on Bank 2 Very High
- Genuine rich condition on Bank 2 Moderate
- Short to voltage in signal wiring Moderate
- Contaminated sensor Low
Frequently Asked Questions
If P0132 is Bank 1 and P0152 is Bank 2, can both appear together?
Yes. If both upstream sensors read high simultaneously, the engine is genuinely running rich on both banks. Check the MAF sensor, fuel pressure regulator, and injectors.
What actually makes the computer set an oxygen sensor code?
The OBD II regulation requires four separate detections for an oxygen sensor (Title 13 CCR 1968.2, section (e)(7.2)): deterioration in voltage, response rate or amplitude that would push emissions past 1.5 times the FTP standards; loss of circuit continuity; out-of-range values; and the case where the sensor has degraded enough that the fuel system stops using it and falls back to open loop. A sensor can therefore set a code while still producing a signal that looks plausible on a scan tool. This is the threshold the monitor is designed around, not a description of your specific fault — the regulation says what the system must detect, not how to find it on your vehicle.
Mechanics Guide Step-by-step diagnosis
Step-by-Step Diagnostic Procedure
-
Monitor Bank 2 Sensor 1 voltage. Stuck above 0.7V constantly indicates a fault.
-
Check Bank 2 fuel trim (LTFT/STFT). If very negative, the engine is genuinely running rich on Bank 2.
-
Investigate Bank 2 fuel delivery: injectors, fuel pressure regulator.
-
Replace sensor if fuel trims are normal but O2 reads constantly high.
Sources 2
This page is built from documented references. Verify against your own service info before repair work.
- California Code of Regulations, Title 13 section 1968.2 (OBD II)malfunction criteria, section (e)
- SAE J2012Diagnostic Trouble Code Definitions (defines the generic OBD-II code ranges)
Commonly Affected Vehicles
- Ford Expedition and F-150 V8
- GM V8 trucks
- Dodge Charger and Ram HEMI
- Toyota Land Cruiser
- Nissan Armada
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