P1702

Symptoms

• Intermittent no-start condition in Park
• harsh or erratic shifting
• blank or incorrect PRNDL display on the dash
• transmission may get stuck in one gear or refuse to shift.

Probable causes

• 1) Faulty transmission range sensor. 2) Damaged wiring or corroded/loose connectors in the transmission range circuit (moisture and corrosion are common contributors). 3) On 2011-2017 Ford F-150s and SUVs
• a failed internal molded lead frame inside the transmission is a very common cause
• repaired via a transmission pan-drop. 4) Failed PCM (least common).

Diagnostic steps

1. Confirm the code and check for related TRS codes (P0705-P0708); because the fault is intermittent, wiggle-test the harness and test-drive while monitoring live data to replicate the dropping signal.
2. Visually inspect the transmission range sensor wiring and connectors for corrosion, broken/bent/pushed-out pins, or damage.
3. Verify power supply (VPWR) to the transmission range sensor at the transmission connector - it should be at or near battery voltage.
4. Test the sensor's resistance and continuity per the service manual; on applicable Fords, scope the TR sensor signal at the PCM connector and confirm it changes correctly in each gear position.
5. Disconnect the transmission connector and the PCM connector and inspect pins for corrosion or looseness.
6. On 2011-2017 F-150/SUV applications, if wiring checks out, suspect the internal molded lead frame - drop the transmission pan and replace it.
7. Only after sensor, wiring, and lead frame are verified good, suspect the PCM. Clear codes and confirm the PRNDL display and starting behavior are correct in all gear positions.