Powertrain, generic (extended)

P2196 O2 Sensor Signal Biased/Stuck Rich (Bank 1, Sensor 1)

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modeNo

P2196 means the front oxygen or air-fuel sensor on bank 1 reports a rich mixture that the ECM does not accept. On GM's Bosch-based 2005 V6 this is a cross-check with the rear sensor: the rear sensor reads lean (below 0.15 V) while the front A/F sensor reads richer than lambda 0.92 and the short-term trim has pulled to its minimum of 0.75, for about 100 s or 50 s in total. Ford sets it for a narrow-band sensor that hardly switches and stays rich, a wide-band sensor that sits 30 s at the short-term trim limit, or, from 2019, a filtered lambda below 1 that changes by less than 0.0001 for 30 s; Ford blocks the stuck-rich test while fuel is boiling off the oil after a cold start. On the Opel/GM 2.0 turbo in the Saab 9-5 (2010) the code sets within 4 s continuously or 50 s in total. Because the ECM leans the engine to follow the false signal, a rear sensor reading lean and a lean real mixture often accompany it.

Likely causes

Front oxygen or A/F sensor contaminated or aged
Sensor signal shorted or reference circuit fault

Symptoms

  • Malfunction indicator lamp on
  • Possible hesitation or lean running

Repair estimate

DifficultyMediumDIY possible
Parts and labour€60–300
Time0.3–1.5 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

oxygen sensor upstreamoxygen sensor wiring

Related codes

P2195P2198P0132P0172P2271

References: fordservicecontent.com, gsi.ext.gm.com, saabwisonline.com.