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DTC codes / Ford codes / P1745

P1745 · FordTransmission system problems

P1745 is a Ford-specific transmission code that the powertrain control module (PCM) sets when it detects a general fault in the transmission control system, often related to the transmission range sensor or internal wiring. The PCM monitors circuit continuity and signal plausibility, and when the expected voltage or resistance falls outside the programmed window, it logs P1745 and may illuminate the malfunction indicator lamp (MIL).

SystemPowertrain
Code typeFord specific
SeverityMedium
Fix difficultyIntermediate
AreaTransmission

Symptoms you may notice

  • Illumination of the malfunction indicator lamp (MIL) on the instrument cluster
  • Often no symptoms besides the warning light, especially if the fault is intermittent
  • Harsh or delayed shifting, or the transmission may default to a limp-home mode
  • Erratic or missing gear engagement, or the selector indicator may not match the actual gear
  • Transmission may slip or fail to downshift when accelerating
  • In some cases, the vehicle may not start if the range sensor signal is implausible

Common causes, most likely first

  1. Faulty transmission range sensor (TRS) or its internal circuitry
  2. Damaged, chafed, or corroded wiring in the transmission harness or connector
  3. Loose or contaminated electrical connector at the transmission or PCM
  4. Internal transmission fault such as a failed solenoid pack or valve body issue affecting range signal
  5. PCM software calibration issue or internal PCM fault (less common)
  6. Poor ground connection for the transmission or PCM circuit

How to diagnose and fix it

  1. Connect a scan tool and retrieve all stored codes, freeze-frame data, and transmission live data to confirm P1745 and check for related codes.
  2. Visually inspect the transmission range sensor connector and wiring harness for damage, corrosion, or loose pins; clean and reseat as needed.
  3. Measure resistance and voltage on the TRS circuit according to Ford service information and compare to specifications.
  4. Check the transmission fluid level and condition; low or degraded fluid can cause erratic sensor signals.
  5. Perform a wiggle test on the harness while monitoring TRS signal on the scan tool to identify intermittent wiring faults.
  6. If the TRS is faulty, replace it and clear the codes; verify the selector lever alignment and adjust if necessary.
  7. If the fault persists, check the PCM for software updates or internal faults, and inspect internal transmission components as needed.

Before you replace the transmission range sensor

  • A loose or corroded connector at the transmission range sensor is a frequent cause of P1745 on Ford vehicles, so always inspect and clean the connector before condemning the sensor.
  • The code can be set by a low battery or charging system issue that causes voltage spikes, so verify battery and charging system health first.
  • P1745 does not always indicate a hard transmission failure; intermittent faults often clear after correcting wiring issues, so avoid unnecessary rebuilds.
  • On some Ford models, the range sensor is integrated into the transmission and requires special tools for replacement, making DIY diagnosis risky.
  • After repairs, a relearn or adaptive shift strategy reset may be required to restore proper shift feel and prevent false re-setting of the code.

Can I keep driving with P1745?

If the vehicle drives normally and the light is steady, you can drive cautiously to a repair shop, but avoid heavy acceleration or towing. If the transmission is in limp mode or shifting erratically, stop driving and seek professional diagnosis to prevent further 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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