Powertrain, generic (extended)

P2255 O2 Sensor Negative Current Control Circuit Low (Bank 2 Sensor 1)

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modeNo

P2255 reports that the negative current control line (reference ground) of the bank 2 upstream wide-band sensor reads too low, typically a short to ground. No manufacturer publicly documents P2255 with thresholds. Ford's OBD summaries assign shorts to ground on any wide-band sensor line to P0151 and use P2254 only for an open line, and VW's 2014 specification books likewise list only P2254. The code therefore appears mainly where the sensor interface separates short-circuit faults by line. CARB requires circuit and out-of-range faults of fuel-control sensors to be detected and, where feasible, stored as separate codes. P2252 is the bank 1 counterpart, P2256 the high-side fault. Mixture control on bank 2 becomes unreliable.

Likely causes

Reference ground wire shorted to ground (chafed against exhaust or body)
Internal fault in the wide-band sensor
Fault in the sensor interface of the ECM

Symptoms

  • Check engine light
  • Higher fuel consumption
  • Possible hesitation or uneven running

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

P2252P2254P2256P0151

References: law.cornell.edu, newtonnet.co.uk, fordservicecontent.com.