Powertrain, generic (extended)

P22B8 O2 Sensor Positive Current Control Circuit/Open (Bank 2 Sensor 2)

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modeNo

P22B8 is the bank 2 version of an open positive current control line on a downstream wide-band probe: the pump-current wire (IP/APE on Bosch) of the sensor behind the catalyst or aftertreatment on the second cylinder bank has lost continuity. It only exists on engines with two exhaust banks and a wide-band probe after each catalyst, which is rare. No maker documents this code publicly. Its bank 1 twin P22AB appears in Chrysler bulletins for the 6.7 Cummins Ram; for the upstream P2240, Ford separates an open pump lead from an open return by pulsing a reference current and checking whether lambda moves by more than 0.05. P22B9/P22BA are low/high, P22BB the reference line. The warning lamp is the main sign.

Likely causes

Loose or corroded pump-current terminal in the sensor connector
Pump-current wire broken near the hot exhaust
Internal open circuit in the bank 2 downstream sensor

Symptoms

  • Check engine light
  • Bank 2 downstream oxygen value missing or frozen

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 bank2 sensor2oxygen sensor wiringecm

Related codes

P22B9P22BAP22BBP22ABP2240

References: law.cornell.edu, newtonnet.co.uk, bosch-motorsport.com.