Powertrain, generic (extended)

P2251 O2 Sensor Negative Current Control Circuit/Open (Bank 1 Sensor 1)

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modeNo

P2251 points to an open negative current control line, i.e. the reference or virtual ground (VM on Bosch, COM on NTK) of the bank 1 upstream wide-band sensor. Ford detects it on Bosch parts by a sensor voltage stuck in a narrow band, or by a reference-current pulse that still moves lambda; NTK chips report the break directly. GM's 2005 V6 and Saab's 2010 9-5 look for 1.47-1.53 V with cell resistance above 570 ohms and exhaust below 900 °C (Type B); VW's 2014 Passat book uses a 950-ohm limit. GM calls it low reference circuit. Bulletins: ECM reflash for the 2020-22 Corvette (22-NA-019) and 2013-14 Dart 2.4 (18-011-14), new sensor for 2016-18 Range Rover TDV6 (LTB01191) and 2025 Wrangler (23-019-25). P2254 is bank 2, P2252/P2253 low/high.

Likely causes

Broken reference ground wire or pushed-back pin between sensor and ECM
Internal open circuit in the wide-band sensor
Engine software that sets the code falsely (reprogramming for some models)

Symptoms

  • Check engine light
  • Higher fuel consumption from open-loop fuelling on bank 1
  • Possible rough running or failed emissions test

Repair estimate

DifficultyMediumDIY possible
Parts and labour€0–450
Time0.3–2 h

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

Parts involved

oxygen sensor bank1 sensor1oxygen sensor wiringecm

Related codes

P2252P2253P2254P2243P2237P0130

References: newtonnet.co.uk, gsi.ext.gm.com, saabwisonline.com, static.nhtsa.gov.