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Pinpoint Test B: Transmission Fluid Temperature (TFT) Sensor

WARNING: This page is about a different car, the 2005 Ford RV Cutaway, 2005 Ford Econoline, and 2005 Ford Cutaway. However, it is still accessible from the selected car via links, so may be relevant.
NOTE: Refer to the TRANSMISSION CONNECTOR LAYOUTS  preceding these pinpoint tests.
  1. B1 ELECTRONIC DIAGNOSTICS 
    • Check to make sure the transmission harness connector is fully seated, pins are fully engaged in connector and in good condition before proceeding.
    • Connect the scan tool.
    • Key in ON position.
    • Select Diagnostic Data Link.
    • Select PCM.
    • Select PID/Data Monitor and Record.
    • Enter the following diagnostic mode on the scan tool: PIDs; TFT, TFTV.
    • Does the vehicle enter PID/Data Monitor and Record? 
  2. B2 WARM-UP/COOL-DOWN CYCLE 
    • While monitoring the TFT PIDs, carry out the following test: If transmission is cold, run transmission to warm it up. If transmission is warm, allow transmission to cool down.
    • Do the TFT PIDs increase as the transmission is warmed up or decrease as the transmission is cooled, or does the TFT or TFTV drop in and out of range? 
    • Yes  : If the TFT PIDs increase as the transmission is warmed or decrease as the transmission is cooled, CLEAR all DTCs. ROAD TEST to verify if concern is still present. If concern is still present, REFER to DIAGNOSIS BY SYMPTOM  to diagnose transmission overheating.

      If the TFT or TFTV drop in and out of range, INSPECT for intermittent concern in the internal/external harness, sensor or connector.

    • No  : GO to B3.
  3. B3 ELECTRICAL SIGNAL CHECK 
    • Key in ON position.
    • Remove transmission fluid pan.
    • Visually inspect the molded lead frame and connectors for damage.
    • Measure the voltage with the positive lead to positive TFT at sensor pin and negative lead to a good ground.
      Fig 1: Measuring Voltage With Positive Lead To Positive TFT At Sensor Pin And Negative Lead To A Good Ground
      G03882366Courtesy of FORD MOTOR CO.
    • Is the voltage present? 
    • Yes  : GO to B4.
    • No  : CHECK for open or short circuit in vehicle harness, internal harness or a PCM concern.
  4. B4 CHECK RESISTANCE OF TFT SENSOR 
    • Disconnect: Transmission Harness.
    • Measure the resistance between the positive TFT and negative TFT pins at transmission connector, using the following:
      TRANSMISSION FLUID TEMPERATURE SPECIFICATIONS

      °C °F Resistance (Ohms)
      -40 to -20 -40 to -4 967K - 284K
      -19 to -1 -3 -31 284K - 100K
      0 - 20 32 - 68 100K - 37K
      21 - 40 69 - 104 37K - 16K
      41 - 70 105 - 158 16K - 5K
      71 - 90 159 - 194 5K - 2.7K
      91 - 110 195 - 230 2.7K - 1.5K
      111 - 130 231 - 266 1.5K - 0.8K
      131 - 150 267 - 302 0.8K - 0.54K
      Fig 2: Measuring Resistance Between Positive TFT And Negative TFT Pins At Transmission Connector
      G03882367Courtesy of FORD MOTOR CO.
    • Is the resistance correct? 
    • Yes  : REFER to DIAGNOSIS BY SYMPTOM  to diagnose an overheating concern.
    • No  : INSTALL a new internal harness (sensor is part of harness).
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