P2198 — O2 Sensor Signal Biased/Stuck Rich Bank 2 Sensor 1

P2198: O2 Sensor Signal Biased/Stuck Rich Bank 2 Sensor 1 — what it means, the affected system and what to check before replacing parts.

Meaning, symptoms, causes and checks

O2 Sensor Signal Biased/Stuck Rich Bank 2 Sensor 1. Basic catalogue definition; diagnostic details have not yet been reviewed.

Affected system: Powertrain

Symptoms

  • The engine warning light may illuminate.
  • Fuel consumption may rise and the engine can hesitate during acceleration.

Possible causes

  • A bank 2 upstream oxygen sensor that is faulty or has damaged wiring may send a persistently rich-biased signal.
  • A leaking injector or excessive fuel pressure may instead cause a real rich exhaust condition.

What to check

  • Read companion codes and inspect the bank 2 sensor 1 harness and connectors when cool.
  • Review the oxygen-sensor live trace and fuel trims to assess whether the signal is misleading or the mixture is rich.
  • Check injector leakage and fuel pressure before changing the oxygen sensor.

Also written as: P2198-00, P219800 (some scan tools add the fault-type byte, e.g. -00).