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P codepowertrainMedium severity

P2709Shift Solenoid "F" Electrical

An electrical fault, such as an open or short, has been detected in the transmission shift solenoid "F" circuit.

Definition

The TCM/PCM monitors the voltage and current of shift solenoid F whenever it drives the solenoid, and P2709 sets when the measured values indicate an open winding, a short, or current outside the expected range. Depending on the transmission, symptoms include harsh or delayed shifts, missing gears, or the transmission entering failsafe (limp) mode locked in a single forward gear, along with an illuminated MIL. Extended driving in failsafe mode elevates transmission fluid temperature and should be avoided.

Common causes

  • Failed shift solenoid F (open or shorted winding)
  • Chafed or broken internal transmission harness
  • Corroded or contaminated transmission case pass-through connector
  • Damaged external harness or poor terminal tension at the TCM
  • Failed TCM solenoid driver (rare)

Common misdiagnoses

  • Complete transmission replacement for a solenoid or wiring fault
  • Valve body replaced when only the solenoid or harness was bad
  • TCM replaced without checking circuit resistance
  • Fluid and filter service expected to fix an electrical fault

Troubleshooting steps

  1. 1.Record codes and freeze frame

    Note temperature, gear, and conditions at the time of failure, and check for companion codes on other solenoids that would point to a shared power feed.

  2. 2.Measure solenoid resistance at the case connector

    Backprobe or unplug the transmission connector and measure shift solenoid F's circuit resistance against the service spec (commonly in the 10-25 ohm range); an open or near-zero reading confirms a solenoid or internal harness fault.

  3. 3.Inspect the pass-through connector

    Look for transmission fluid wicking into the connector, spread terminals, and corrosion, which are frequent causes of solenoid circuit codes.

  4. 4.Test the external harness

    Check continuity and shorts to ground/voltage on the circuit between the case connector and the TCM while flexing the harness.

  5. 5.Command the solenoid with a scan tool

    Use bidirectional control to activate solenoid F and verify current draw or an audible click; no response with good wiring condemns the solenoid.

  6. 6.Repair and road-test

    Replace the solenoid or repair wiring as found, clear codes, and verify correct shift points through all gears on a road test.

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