Powertrain, generic (extended)

P2628 O2 Sensor Pumping Current Trim Circuit High (Bank 1 Sensor 1)

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modeNo

With P2628 the trim input of the front wide-band probe on bank 1 lies above its permitted range. Ford's 2020-23 petrol summary reserves it for NTK probes, where the interface chip reports the resistor line shorted to battery voltage. In GM's 2005 table for the Honda-sourced 3.5 L V6 it is the opposite end of P2627: the label resistor voltage drops under 0.29 V for 5 s. GM diesels apply it to the NOx sensor oxygen value downstream of the turbine; the 2020 table counts readings above 27 percent, i.e. more oxygen than air, in 100 of 200 samples and only while exhaust pressure is plausible (type B). A trim value out of range skews the lambda value the probe reports, so the module stops trusting the probe. Low is P2627, open P2626, bank 2 high P2631.

Likely causes

Trim line shorted to battery or another supply in the harness or plug
Wide-band probe or NOx sensor delivering an implausible value
Exhaust leak ahead of the sensor drawing in outside air

Symptoms

  • Check engine light
  • Mixture control without probe feedback, higher consumption
  • On diesels NOx-related codes and possible SCR warnings

Repair estimate

DifficultyMediumDIY possible
Parts and labour€0–450
Time0.3–2 h

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

Parts involved

oxygen sensor bank1 sensor1sensor calibration resistornox sensoroxygen sensor wiring

Related codes

P2626P2627P2631P2237P0132

References: fordservicecontent.com, gsi.ext.gm.com, gsi.ext.gm.com, bosch-motorsport.com.