Powertrain, generic (extended)

P2AEF Intake Air O2 Sensor Negative Current Control Circuit Open Bank 2

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modeNo

P2AEF indicates that the return line, or virtual ground, of the bank 2 intake oxygen sensor is open. Both cells of a wide-band element reference this lead, pin 2 (IPN/VM) on the Bosch LSU 4.9, which the ECM biases so current can flow both ways. Ford's 2012 summary describes the bank 2 exhaust analog P2254: if the sensor voltage settles inside a narrow band (1.45-1.55 V with the Bosch CJ125, 1.95-2.05 V with the Conti ATIC42) for 10 s, the return is judged open. Nothing comparable is published for an intake sensor, and no maker documents P2AEF. A second intake sensor exists only where every bank has a separate intake or EGR route. While the return is open, bank 2 EGR loses its feedback; drivers usually see only the lamp. P2AF0/P2AF1 are low/high, P2AEC the open pump lead, P2AE6 bank 1.

Likely causes

Return lead (pin 2) broken
Return contact corroded or loose
Internal break of the common electrode

Symptoms

  • Check engine light on
  • Usually no noticeable change in driveability

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

intake air o2 sensor b2wiring harnessecm

Related codes

P2AF0P2AF1P2AECP2AE6P2254

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