Split, disconnected, or leaking charge-air hose or intercooler pipe; Faulty manifold absolute pressure (MAP) sensor or boost pressure sensor; Sticking or failed turbocharger wastegate or variable-geometry turbo actuator; Clogged or restricted air intake or air filter; Exhaust restriction upstream of the turbo, such as a blocked diesel particulate filter; Wiring damage or poor connection at the MAP or boost sensor; Turbocharger internal failure, such as seized vanes or a damaged compressor wheel

DTC codes / Ford codes / P1248

P1248 · FordTurbo Boost Pressure Not Detected

Q: What does code P1248 mean?

Turbo Boost Pressure Not Detected. P1248 on Ford vehicles means the powertrain control module (PCM) commanded a turbo boost condition but did not see the expected rise in boost pressure from the manifold pressure sensor. The PCM compares desired boost against actual measured boost and flags this code when the actual value stays too low for the operating conditions.

P1248 on Ford vehicles means the powertrain control module (PCM) commanded a turbo boost condition but did not see the expected rise in boost pressure from the manifold pressure sensor. The PCM compares desired boost against actual measured boost and flags this code when the actual value stays too low for the operating conditions.

SystemPowertrain

Code typeFord specific

SeverityMedium

Fix difficultyIntermediate

AreaFuel and air metering (injector circuits)

Symptoms you may notice

Illumination of the check engine light, often with no other noticeable symptoms
Reduced engine power or a limp-home mode feeling during acceleration
Sluggish throttle response and poor acceleration from a stop
Noticeable lack of turbo boost, especially during highway merging or passing
Possible black smoke from the exhaust under load on diesel models
Rough running or hesitation under acceleration

Common causes, most likely first

Split, disconnected, or leaking charge-air hose or intercooler pipe
Faulty manifold absolute pressure (MAP) sensor or boost pressure sensor
Sticking or failed turbocharger wastegate or variable-geometry turbo actuator
Clogged or restricted air intake or air filter
Exhaust restriction upstream of the turbo, such as a blocked diesel particulate filter
Wiring damage or poor connection at the MAP or boost sensor
Turbocharger internal failure, such as seized vanes or a damaged compressor wheel

How to diagnose and fix it

Inspect all charge-air hoses and intercooler pipes for splits, loose clamps, or disconnected joints
Check the air filter and intake tract for blockage or collapse
Use a scan tool to read live boost pressure and compare commanded versus actual boost
Test the MAP or boost pressure sensor signal and wiring for opens, shorts, or corrosion
Verify wastegate or variable-geometry turbo actuator movement and vacuum or electronic control
Check for exhaust restrictions, especially on diesel models with a particulate filter
If all external checks pass, perform a turbocharger inspection for internal damage or seizure

What Ford techs check before replacing the turbo

A loose or cracked intercooler pipe is the most common cause of P1248 on Ford vehicles, and it often looks fine until you pressurize the system.
The code can set from a lazy MAP sensor that still reads plausibly at idle but fails to respond quickly under boost.
On Ford diesels, a partially blocked diesel particulate filter can restrict exhaust flow enough to prevent boost from building without setting a filter-specific code.
A sticking wastegate or carboned-up variable-geometry turbo mechanism can cause this code without any boost leak at all.
Do not replace the turbocharger based on this code alone; verify actual boost pressure with a gauge or scan tool first.

Can I keep driving with P1248?

You can usually drive the vehicle gently to a repair shop, but avoid hard acceleration and heavy loads because the engine is running without proper boost control. Continued driving with a significant boost leak or turbo fault can lead to over-fueling, higher exhaust temperatures, and further damage.

Tools that help

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Guidance is general and written for Ford vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.