Powertrain, generic (extended)

P259E Turbocharger A Boost Control Position At Low Limit

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modePossible

P259E means the boost control of turbocharger A has run out of range at the low end: the actuator is at its limit, yet boost stays well under the target. Ford's 2023 diesel OBD summary places it in the underboost monitor. With closed-loop boost control active, at least 50 Nm (6.7 L) or 135 Nm (3.0 L) and 800 or 1300 rpm, it sets when desired boost exceeds actual boost by more than 120 kPa (6.7 L) or 80 kPa (3.0 L) for roughly 10-11 s. Ford's special service message 50564 for 2020-2022 Super Duty 6.7 L lists P259E among turbo-related codes and makes the variable vane actuator available on its own, so the whole turbocharger need not be replaced. P259F is the opposite limit, P2263 the slower general boost performance check, P0299 plain underboost.

Likely causes

Leak in charge air pipes, intercooler or clamps
Variable vane actuator or vane mechanism not reaching the commanded position
Exhaust leak upstream of the turbine
Boost pressure sensor reading too low

Symptoms

  • Engine warning lamp on
  • Clear loss of power under load
  • Whistling or hissing from the charge air side

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€50–2,000
Time0.5–5 h

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

Parts involved

turbo actuator aboost control loop

Related codes

P259FP25A0P2263P0299P2598

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