Powertrain, generic (extended)

P2AB3 Cold Start Intake Manifold Runner Control Stuck Open Bank 1

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modeNo

P2AB3 is part of the cold-start component checks that CARB phases in for 20, 50 and 100 percent of new vehicles in 2026, 2027 and 2028. Right after a start that follows a long standstill, charge motion, runner and swirl valves must follow the cold-start command clearly, toward the target and further than they would at a start without that strategy. The test only counts after at least six hours off, at -6.7 °C or warmer, with coolant no more than 15 °C above ambient. P2AB3 means the runner control on bank 1 stays in its open position when the cold-start strategy calls for a change. No manufacturer documents P2AB3 publicly. For comparison, Ford's ordinary IMRC check runs continuously above 40 °F coolant and judges stuck plates after 4 events (P2004). Weaker mixture motion raises cold emissions.

Likely causes

Actuator or vacuum unit too weak to move the flaps when cold
Flap shaft stiff from carbon or oil deposits
Linkage detached or broken between actuator and shaft

Symptoms

  • Check engine light on
  • Rougher idle in the first minutes after a cold start
  • Higher cold-start emissions, otherwise often unnoticed

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€50–1,200
Time0.5–5 h

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

Parts involved

imrc actuator b1intake manifold runners

Related codes

P2AB4P2AB5P2AB6P2004P2006

References: law.cornell.edu, fordservicecontent.com.