P0050: HO2S Heater Control Circuit (Bank 2 Sensor 1)

What does P0050 mean?

The computer cannot operate or monitor the heater of the upstream exhaust sensor on bank 2 correctly. Bank 2 is the side without cylinder 1. This heater fault can delay mixture-feedback readiness on that side even though the sensor signal circuit and catalytic converter are otherwise intact.

Generic OBD-II definition: HO2S Heater Control Circuit (Bank 2 Sensor 1). Confirm applicability in your vehicle service information.

Common causes

• Open bank 2 upstream heater
• Missing heater power feed
• Broken or corroded heater wiring

Symptoms

• Check engine light
• Slow entry into closed-loop fuel control
• Possible decrease in fuel economy

Diagnostic focus

Locate the upstream sensor on the bank without cylinder 1. Testing the bank 1 sensor by mistake will not diagnose this circuit; compare shared heater supply operation if both banks have codes.

Can I keep driving with P0050?

Severity: Medium If the engine runs normally and the light is steady, arrange emissions-system diagnosis. Stop for a flashing light or severe roughness; those symptoms need separate urgent attention.

If the check engine light is flashing or the car runs badly, stop driving and have it checked.

Typical fixes

• Allow the exhaust to cool before inspecting wiring
• Compare bank 2 heater feed and operation with bank 1, using the engine wiring diagram.
• Repair wiring or replace the correct sensor only when the fault is confirmed

Sources & review

• OBD-Codes.com: P0050
• TroubleCodes.net: generic code definitions

Definitions and diagnostic background checked 2026-11-06. Generic guidance, not a substitute for the service procedure for your exact year, engine, and transmission.