Powertrain, generic (extended)

P2254 O2 Sensor Negative Current Control Circuit/Open (Bank 2 Sensor 1)

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modeNo

P2254 concerns the negative current control line - also called reference ground, virtual ground or COM - of the wide-band air-fuel sensor ahead of the catalyst on bank 2. Ford's OBD summaries (2012 and 2020-2023) set it for an open line: with Bosch sensors the PCM briefly injects a reference current and flags the line if lambda barely moves, within about 10 s; with NTK sensors the interface chip reports the open line directly. VW's 2014 Passat and CC books set it when the front signal sits at 1.47-1.52 V while the cell resistance exceeds 950 ohms. P2251 is the same fault on bank 1, P2255/P2256 are low/high faults. Closed-loop mixture control on bank 2 is lost.

Likely causes

Broken reference ground wire or pushed-out pin between sensor and ECM
Internal open circuit in the wide-band sensor
Corroded sensor connector with high contact resistance

Symptoms

  • Check engine light
  • Higher fuel consumption from open-loop fuelling on bank 2
  • Possible rough running or failed emissions test

Repair estimate

DifficultyMediumDIY possible
Parts and labour€80–400
Time0.5–2 h

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

Parts involved

oxygen sensor bank2 sensor1oxygen sensor wiringecm

Related codes

P2251P2255P2256P2247P2240P0150

References: law.cornell.edu, newtonnet.co.uk, static.nhtsa.gov, static.nhtsa.gov.