P259E code meaning
Turbocharger A Boost Control Position At Low Limit
Powertrain system Generic code P25xx codes Check engine light
What P259E means
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.
P259E at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyMedium
- Typical labor0.5 to 5 hours
- Clears after repairAfter a drive cycle
Symptoms of P259E
- Engine warning lamp on
- Clear loss of power under load
- Whistling or hissing from the charge air side
Common causes of P259E
- Most likelyLeak in charge air pipes, intercooler or clamps
- PossibleVariable vane actuator or vane mechanism not reaching the commanded position
- PossibleExhaust leak upstream of the turbine
- Less likelyBoost pressure sensor reading too low
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Turbo actuator aBoost control loop
What each part of P259E means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 2 | Generic code (second SAE range): it means the same on every make. |
| 5 | Area: vehicle speed, idle control and auxiliary inputs. |
| 9E | The exact fault in that area. |
What to do next
- Note P259E and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P259E
What does P259E mean?
P259E means "Turbocharger A Boost Control Position At Low Limit". 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. It is a generic code, so it means the same on every make.
Is it safe to drive with P259E?
Drive gently and only to a workshop. With P259E the car can go into limp mode (reduced power) to protect itself.
Will P259E fail an emissions test?
Yes, it can. P259E is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P259E to fix?
Difficulty: medium. A typical repair takes 0.5 to 5 hours of work. This is a job for a workshop.
Will P259E clear itself after the repair?
After the repair the car has to complete a drive cycle (a mix of city and highway driving) before the test runs again. Until then the readiness monitor shows "not ready", which can fail an inspection.