Powertrain, generic (extended)

P2195 O2 Sensor Signal Biased/Stuck Lean (Bank 1, Sensor 1)

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modeNo

P2195 means the front oxygen or air-fuel sensor on bank 1 reports a lean mixture that the ECM does not believe, either because it stays lean or because it disagrees with other evidence. On GM's Bosch-based 2005 V6 the rear sensor has to read rich (above 0.85 V) while the front A/F sensor reads leaner than lambda 1.08 and the short-term trim sits at its maximum of 1.25, for about 100 s or 50 s in total. Ford checks narrow-band sensors for fewer than 5 switches in 30 s and wide-band sensors for 30 s at the short-term trim limit; from 2019 a sensor whose filtered lambda changes by less than 0.0001 for 30 s sets P2195 if the value is at or above 1. 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. Ford replaced the heated oxygen sensors for P2195 and P2197 on 2015 to 2017 Explorer and F-150 3.5 GTDI. An exhaust leak ahead of the sensor can also make it read lean.

Likely causes

Front oxygen or A/F sensor aged or contaminated
Exhaust leak ahead of the sensor
Sensor signal or reference wiring fault

Symptoms

  • Malfunction indicator lamp on
  • Possible rough running or higher consumption from wrong fuelling

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 wiringexhaust manifold

Related codes

P2196P2197P0131P0171P2270

References: fordservicecontent.com, gsi.ext.gm.com, saabwisonline.com, static.nhtsa.gov.