Powertrain, generic (extended)

P22C3 O2 Sensor Pumping Current Trim Circuit Low (Bank 2 Sensor 2)

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modeNo

P22C3 is the low fault on the trim (label resistor) circuit of the bank 2 post-catalyst wide-band probe. Ford's 2012 OBD summary shows how makers can read this for NTK probes: at each key-on the controller switches the heater off, samples a voltage divider and estimates the label resistor; a value too high is taken as a broken or grounded lead and sets the trim-low code (P2630 for the bank 2 front probe). The controller then falls back to the resistor rank stored in memory, so the reading stays usable but less exact. No maker documents P22C3 publicly, and GM reuses the bank 1 slot P22B6 for a NOx sensor oxygen check without a bank 2 equivalent. P22C2 is the open, P22C4 the high variant. The lamp lights.

Likely causes

Trim wire chafed and shorted to ground
High-resistance or corroded trim terminal raising the measured resistance
Defective label resistor in the sensor connector

Symptoms

  • Check engine light
  • Code typically appears right after engine start

Repair estimate

DifficultyMediumDIY possible
Parts and labour€0–450
Time0.5–2 h

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

Parts involved

oxygen sensor bank2 sensor2oxygen sensor wiringecm

Related codes

P22C2P22C4P22B6P2630

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