Powertrain, generic (extended)

P2BAC NOx Exceedence - Deactivation of EGR

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modePossible

P2BAC is reserved for the case where exhaust gas recirculation is not just off target but shut down altogether, whether by an unplugged valve, a blocked path, an unauthorised software change or a defect that leaves the valve closed. The European rules treat this as a typical tampering scenario: Regulation (EU) No 582/2011, Annex XIII, carries an EGR valve counter that ends first in a warning and then in inducement. California's rule, section (f)(6.2.1) of 13 CCR 1968.2, requires a malfunction when EGR flow is absent although expected. No maker documents P2BAC publicly. Compared with P2BAB, which covers wrong flow, this code needs a hard stop; component codes for valve circuit or position usually come along and point to the cause.

Likely causes

EGR valve unplugged, blanked off or disabled
EGR valve stuck closed or actuator failed
Modified engine software with EGR switched off
Open or short in the EGR valve circuit

Symptoms

  • MIL and NOx warning, later inducement
  • Harder, louder combustion
  • EGR circuit or position codes stored as well

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€100–1,200
Time0.5–4 h

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

Parts involved

egr valve

Related codes

P2BABP0400P0401

References: legislation.gov.uk, law.cornell.edu.