P0152
O2 Sensor Circuit High Voltage (Bank 2 Sensor 1)
The appearance of the standard OBD2 trouble fault code P0152 is an indicator that your vehicle ECU triggered a threshold alert for "O2 Sensor Circuit High Voltage (Bank 2 Sensor 1)". Understanding the root component breakdown helps avoid expensive diagnostic fees.
Driver's Summary
Storing code P0152 is your car's way of telling you something is wrong with the o2 sensor circuit high voltage (bank 2 sensor 1). The most common signs are black smoke, rough idle, poor fuel economy. While the car is usually drivable, you should schedule a diagnosis within the next few days to prevent the issue from worsening.
Symptoms
Black smoke, rough idle, poor fuel economy
Common Causes
- Leaking fuel injector on Bank 2
- Defective upstream O2 sensor
- Short to voltage in O2 circuit
- Restricted air intake
How to Fix
- 1 Test and replace leaky injectors
- 2 Replace Bank 2 upstream O2 sensor
- 3 Repair wiring short
- 4 Check engine air filter
Technical Explanation
P0152 is stored after the control module confirms the fault over multiple ignition cycles, ruling out transient electrical noise as the cause. The diagnostic runs during closed-loop operation only, ensuring the engine is at full operating temperature and the PCM's fuel trim feedback loop is active before confirming any out-of-range condition. After two failed drive cycles, the code transitions from a pending to a confirmed DTC, and the PCM activates the MIL. Clearing the code without repairing the fault will result in re-illumination within one to two complete drive cycles.
Is It Safe to Drive?
Medium-severity fault: the car functions but not optimally. The leaking fuel injector on bank 2 issue will not resolve itself and will cause measurable long-term wear. A repair in the $50–$500 range now avoids far higher costs later.
Mechanic's Pro Tip
For P0152, always perform a smoke test before replacing any parts — unmetered air from a cracked intake boot, split hose, or failed gasket is the root cause in the majority of lean fault cases and costs almost nothing to fix. After any repair, clear the code and watch short-term fuel trim (STFT) live on a scan tool; it should recover to within ±5% at idle within 2–3 minutes if the vacuum leak is truly resolved.
O2 sensor: $150 - $300; Injectors: $200 - $500