Powertrain, generic (extended)

P2631 O2 Sensor Pumping Current Trim Circuit High (Bank 2 Sensor 1)

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modeNo

P2631 flags a trim value above the valid window for the first wide-band probe on bank 2. Ford assigns it to NTK probe installations: the interface chip notices the resistor line pulled up to battery voltage, as from a chafed wire touching a powered circuit. GM's 2005 table for the 3.5 L V6 of Honda origin uses the mirror logic, with the bank 2 label resistor voltage below 0.29 V for 5 s. CARB requires front air-fuel ratio sensors to be checked for wiring defects and for readings beyond their valid span that would disable closed-loop fuelling, which is what such a reading does. A harness short can also hit other circuits in the same loom, so check for neighbouring codes first. Bank 1 high is P2628; P2630 is the low fault and P2629 the open fault on this probe.

Likely causes

Bank 2 resistor line shorted to a powered wire in the harness
Bank 2 front probe with internal short
Non-matching replacement probe or repaired connector without the original resistor

Symptoms

  • Check engine light
  • Lambda control on bank 2 disabled
  • Possibly additional circuit codes from the same harness

Repair estimate

DifficultyMediumDIY possible
Parts and labour€0–350
Time0.3–2 h

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

Parts involved

oxygen sensor bank2 sensor1sensor calibration resistoroxygen sensor wiring

Related codes

P2628P2629P2630P2240P0152

References: fordservicecontent.com, gsi.ext.gm.com, law.cornell.edu.