Faulty electronic pressure control (EPC) solenoid; Damaged or corroded wiring harness or connector at the transmission; Sticking or contaminated transmission valve body; Low or degraded transmission fluid; Failed transmission fluid pressure sensor (TFPS) or related sensor; Internal transmission mechanical wear affecting line pressure; PCM software or internal fault (rare)

DTC codes / Ford codes / P1748

P1748 · FordEPC Malfunction

Q: What does code P1748 mean?

EPC Malfunction. P1748 on Ford vehicles indicates that the powertrain control module (PCM) has detected a malfunction in the electronic pressure control (EPC) circuit, which manages transmission line pressure. The PCM monitors the EPC solenoid's electrical circuit and hydraulic response, and it sets this code when the commanded pressure does not match the actual pressure or when the circuit is out of range.

P1748 on Ford vehicles indicates that the powertrain control module (PCM) has detected a malfunction in the electronic pressure control (EPC) circuit, which manages transmission line pressure. The PCM monitors the EPC solenoid's electrical circuit and hydraulic response, and it sets this code when the commanded pressure does not match the actual pressure or when the circuit is out of range.

SystemPowertrain

Code typeFord specific

SeverityMedium

Fix difficultyProfessional

AreaTransmission

Symptoms you may notice

Illumination of the transmission control indicator lamp (TCIL) or check engine light
Harsh or delayed transmission shifts, especially when cold
Transmission slipping or flaring during gear changes
Erratic shift points or failure to shift into certain gears
Limp-home mode with reduced engine power and fixed gear
Often no symptoms besides the warning light, especially if the fault is intermittent

Common causes, most likely first

Faulty electronic pressure control (EPC) solenoid
Damaged or corroded wiring harness or connector at the transmission
Sticking or contaminated transmission valve body
Low or degraded transmission fluid
Failed transmission fluid pressure sensor (TFPS) or related sensor
Internal transmission mechanical wear affecting line pressure
PCM software or internal fault (rare)

How to diagnose and fix it

Check transmission fluid level and condition; top off or replace if contaminated
Inspect the EPC solenoid connector and wiring for corrosion, chafing, or loose pins
Measure the resistance of the EPC solenoid and compare to Ford specifications
Perform a line pressure test to verify actual hydraulic pressure against commanded values
Use a scan tool to command the EPC solenoid and observe pressure changes
Remove the transmission pan and inspect the valve body and solenoid for debris or sticking
Replace the EPC solenoid or valve body as needed, then clear codes and verify repair

EPC circuit faults often misdiagnosed

A sticking valve body spool can mimic a failed EPC solenoid, so always verify hydraulic pressure before replacing parts.
Corroded pins in the transmission connector are a common cause on high-mileage Ford vehicles, often overlooked during diagnosis.
The EPC solenoid is pulse-width modulated; a failed solenoid may still test good with a simple resistance check, so dynamic testing is essential.
Low fluid level from a slow leak can set P1748 without any visible leak on the ground, especially on models with a sealed transmission.
After repairs, the PCM may require a relearn procedure or adaptive shift strategy reset to prevent repeat codes.

Can I keep driving with P1748?

Driving with P1748 can lead to increased transmission wear and potential damage if the EPC system is not functioning correctly. Avoid heavy acceleration or towing, and have the vehicle diagnosed promptly; if the transmission enters limp mode, limit driving to a safe location.

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.