P2256O2 Sensor Heater Control Circuit Low Bank 1 Sensor 2
The ECU detects a low-side voltage below threshold on the heater control of the rear oxygen sensor on bank 1. The heater driver may be stuck on or shorted to ground.
Can I keep driving? With caution
You can drive to the shop, but do not postpone the repair. The problem may worsen and damage other components.
Sistema Afectado
Motor · Powertrain
La falla pertenece al grupo motopropulsor (motor y gestión electrónica).
Espacio para vendedores de repuestos
Aún no hay un anunciante en este espacio.
Symptoms You Will Notice
What you may observe when this code appears
- Check engine light on after several drive cycles Slightly increased fuel consumption during cold start Delayed entry into closed-loop fuel control Failed emissions inspection (lambda readiness)
Possible Causes
The components or conditions that trigger this code
- 1Heater wire shorted to ground Internal heater short Connector pins corroded - high contact resistance
How to Fix It — Step by Step
Recommended diagnostic and repair procedure
- 1Difficulty: medium. Estimated time: 0.5-1.5 hours. Estimated cost: €100-€
- 2DIY possible
Note: This information is for general reference. For precise diagnostics and safety repairs, always consult a certified mechanic.
Estimated Cost
Approximate range in USD (varies by region and shop)
Varies by diagnosis
* Diagnosis only: $50–$150
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