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DTC codes / Ford codes / P1746

P1746 · FordElectronic Pressure Control Solenoid A Open Circuit

P1746 on Ford vehicles means the transmission control module (TCM) has detected an open circuit in the electronic pressure control (EPC) solenoid A circuit, so the solenoid is not receiving the electrical current it needs to regulate hydraulic pressure. The TCM commands a specific current to the solenoid and monitors the return circuit; when the measured current falls outside the expected range or the circuit shows infinite resistance, it sets this code and typically defaults the transmission to a high-pressure limp mode.

SystemPowertrain
Code typeFord specific
SeverityMedium
Fix difficultyIntermediate
AreaTransmission

Symptoms you may notice

  • The check engine light or transmission warning light illuminates on the dashboard.
  • Harsh or delayed shifts, often described as a firm slam into gear, especially when selecting drive or reverse.
  • The transmission may default to a fixed high line pressure, causing every shift to feel abrupt.
  • In some cases the transmission enters limp mode and stays in a single gear or refuses to downshift.
  • Often no symptoms besides the warning light, particularly if the open circuit is intermittent and the solenoid still functions under most conditions.

Common causes, most likely first

  1. A broken, chafed, or corroded wire in the EPC solenoid A circuit between the TCM and the transmission connector.
  2. A loose, contaminated, or water-intruded transmission range sensor or solenoid body connector.
  3. An open winding inside the EPC solenoid itself, which fails the TCM's current-rise test.
  4. A faulty transmission control module (TCM) driver circuit that cannot supply current to the solenoid.
  5. Corrosion or pin fit issues at the TCM harness connector, common on older Ford trucks and SUVs exposed to road salt.
  6. A shorted or open trace on the solenoid body assembly internal harness, especially after fluid contamination or valve body work.

How to diagnose and fix it

  1. Scan all modules and record freeze-frame data for P1746, then clear the code and verify whether it returns immediately or only after a drive cycle.
  2. Inspect the transmission connector and solenoid body connector for corrosion, bent pins, or fluid intrusion, and clean or repair as needed.
  3. Measure resistance of the EPC solenoid A winding at the transmission connector and compare to the Ford service specification for the specific transmission.
  4. Check continuity and voltage drop on the EPC solenoid A feed and ground wires from the TCM to the transmission connector while wiggling the harness to catch intermittent opens.
  5. If the circuit tests good, command the EPC solenoid with a bidirectional scan tool and watch for current and pressure response to confirm whether the solenoid or TCM is at fault.
  6. Replace the EPC solenoid or solenoid body assembly if the winding is open, following Ford's fluid and torque procedures.
  7. If the TCM driver circuit is confirmed open, replace or reprogram the TCM and perform the adaptive learning relearn procedure.

What Ford techs check before replacing the solenoid

  • A P1746 is frequently caused by a chafed harness near the transmission bellhousing or exhaust heat shield rather than by the solenoid itself, so always inspect the wire routing before condemning the part.
  • On many Ford transmissions the EPC solenoid shares a connector with the shift solenoids, and fluid wicking through the connector pins can create an open circuit that only appears when the transmission is hot.
  • An intermittent P1746 that clears after a key cycle is often a pin fit issue at the TCM connector, not a failed solenoid, and replacing the solenoid will not fix it.
  • The TCM may set P1746 as a companion code when the transmission is low on fluid or the filter is restricted, because the solenoid current rise time changes when hydraulic load is abnormal.
  • Do not overlook the transmission range sensor on models where it is integrated into the solenoid body harness; a faulty sensor can interrupt the shared ground and trigger a false open-circuit code.

Can I keep driving with P1746?

You can usually drive the vehicle to a shop, but expect harsh shifts and possible limp mode, so avoid heavy throttle, towing, or highway merging until the fault is repaired. If the transmission slips or refuses to engage a gear, stop driving and have it towed to prevent internal damage.

Tools that help

Tools we recommend are in the Auto Veteran shop on Amazon. As an Amazon Associate we earn from qualifying purchases.

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

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