OBD-II code · Powertrain (generic, extended)

P2198 O2 Sensor Signal Stuck Rich (Bank 2, Sensor 1)

The upstream oxygen sensor on bank 2 returns a constant rich signal under deceleration fuel cut-off where lean is expected. Often a contaminated sensor (silicone, oil, coolant) or short to ground that pulls the signal high in some sensor types.

Is it safe to drive with P2198?

Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.

Common causes

  • Most likelyUpstream sensor contaminated

Symptoms

  • Check engine light on
  • Increased fuel consumption
  • Possible rough idle or hesitation
  • Failed emissions test

Repair at a glance

Difficulty
Medium
DIY friendly
Often, with basic tools
Typical labour
0.3–2 h
Emissions test
Likely to fail
After the fix
A drive cycle is needed before the light stays off
Parts involved
Oxygen Sensor Upstream

Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.