OBD-II Code · Sensors
P0152
O2 Sensor High Voltage (B2S1)
Bank 2 upstream sensor voltage high.
Common symptoms
- CEL
- Black smoke
Likely causes
- Rich condition
- Failed sensor
- Contamination
Where to start
- Try the cheapest cause first. Start by checking: rich condition.
- Cost & scope. $150-$400
- If the code returns after the fix: escalate to a shop or scanner with live-data and freeze-frame. A code that re-sets means the underlying fault is still there.
Read the full diagnostic procedure
P0152 is bank 2 upstream signal stuck HIGH — the bank-2 inverse of P0132. Engine appears permanently rich on bank 2. Cheapest-first ladder: check fuel trims; if B2 LTFT is pegged at -15 to -25%, the engine really IS rich on that bank — leaking injector on bank 2, stuck-open EVAP purge solenoid (purges typically dump into a specific intake runner, so they can bias one bank), failed FPR dumping fuel through the vacuum reference, or a bank-2-specific fuel rail leak. If fuel trims are normal, the signal is being held high by wiring — usually a heat-damaged connector where signal has bled into the heater B+ rail. Same FSM bank-verification rule applies: don't replace the wrong sensor.
Vehicle-specific patterns
Vehicle-specific patterns: 2004-2008 Dodge Ram 5.7L Hemi — longitudinal, bank 2 is driver side; throws P0152 from leaking driver-side injectors (Mopar TSB on injector pintle seal failure). 2006-2012 Toyota RAV4 V6 / Highlander 2GR-FE — bank 2 is front (transverse); sets P0152 from FPR diaphragm tear dumping fuel into the manifold. 2008-2014 Cadillac CTS 3.6L LLT direct-injection — bank 2 is front; throws P0152 from a stuck-open high-pressure injector. 2007-2013 Nissan Pathfinder / Frontier VQ40 — bank 2 is driver side (longitudinal); sets P0152 from a saturated EVAP canister venting into the bank-2 intake runner. Cost band: $200-$500 for sensor; $400-$1,500 if a leaking injector or FPR is the real cause.
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