Powertrain, generic (extended)

P2439 AIR System Air Flow/Pressure Sensor Circuit Intermittent/Erratic (Bank 2)

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modeNo

P2439 covers brief dropouts or jumps in the bank 2 secondary air pressure signal. No manufacturer documents this code publicly; the description rests on CARB's demand that every electrical AIR component be checked for circuit faults and rationality, together with the bank 2 sensor layout known from Audi's R8 V10 (sensor G610). Unlike with P2437 or P2438, the signal is valid most of the time, so the fault often vanishes at the workshop. Freeze-frame data, shaking the harness on the exhaust side and looking for heat-hardened insulation or green terminals are the practical steps. Bank 1 uses P2434; a lasting fault would show up as P2435–P2438 instead.

Likely causes

Loose or corroded terminal at the bank 2 sensor
Harness near the exhaust side brittle or chafed
Intermittent internal sensor fault

Symptoms

  • Warning lamp appears now and then
  • Code returns after clearing without visible cause

Repair estimate

DifficultyMediumDIY possible
Parts and labour€30–350
Time0.5–3 h

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

Parts involved

air system flow sensor b2sai wiring

Related codes

P2434P2435P2437P2438

References: law.cornell.edu, static.nhtsa.gov.