Powertrain, generic (extended)

P22B2 O2 Sensor Negative Current Control Circuit/Open (Bank 1 Sensor 2)

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modeNo

P22B2 indicates an open negative current control line on the bank 1 downstream wide-band probe. This is the shared return of pump and sensing cell, the virtual ground (VM/IPN on Bosch, COM on NTK), which the controller holds at a mid-level bias of around 2.5 V. Chrysler lists the code for 2010-2012 Ram 2500/3500 with the 6.7 Cummins and repairs connectors and wiring first; GM names it in 21-NA-149 for the 3.0 Duramax LM2. For the upstream twin P2251, Ford sees an open return as a sensor voltage stuck near 1.5 V for 10 s, GM and Saab as 1.47-1.53 V with cell resistance above 570 ohms. P22B3/P22B4 cover low/high, P22BF bank 2. The warning lamp lights; drivability normally stays the same.

Likely causes

Loose, corroded or pushed-back terminal on the return wire
Return (virtual ground) wire broken in the harness
Internal open circuit in the downstream wide-band sensor

Symptoms

  • Check engine light
  • Downstream oxygen reading frozen near a fixed value
  • Aftertreatment readiness not set

Repair estimate

DifficultyMediumDIY possible
Parts and labour€0–450
Time0.5–2.5 h

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

Parts involved

oxygen sensor bank1 sensor2oxygen sensor wiringecm

Related codes

P22B3P22B4P22ABP22AEP22BFP2251

References: static.nhtsa.gov, static.nhtsa.gov, static.nhtsa.gov, newtonnet.co.uk.