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Home >> Ford >> 2000 >> Taurus LX, 3.0 2, AX4N >> Repair and Diagnosis >> External Pages >> Different car >> Section 1291 (Automatic Transmission - 4R70E/W, 4R75E/W) >> Diagnostic Tests >> Pinpoint Tests - OSC Equipped Vehicle >> Pinpoint Tests >> Pinpoint Test B: Transmission Fluid Temperature (TFT) Sensor

Pinpoint Test B: Transmission Fluid Temperature (TFT) Sensor

WARNING: This page is about a different car, the 2008 Ford RV Cutaway, 2008 Ford Econoline, and 2008 Ford Cutaway. However, it is still accessible from the selected car via links, so may be relevant.
NOTE: Refer to the Transmission Internal Harness Connector illustration in Transmission Connector Layouts .
  1. B1 ELECTRONIC DIAGNOSTICS 
    • Vehicle in PARK.
    • Key in OFF position.
    • 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 diagnostic tool.
    • Key in ON position.
    • Access the transmission PIDs.
    • Is the scan tool able to access the transmission PIDs? 
    1. YES  : Go to  B2.
    2. NO  : REPEAT procedure to access the transmission PIDs. If the scan tool did not access the transmission PIDs, REFER to the appropriate Engine Performance article for diagnosis of PCM.
  2. B2 WARM-UP/COOL-DOWN CYCLE 
    • While monitoring the transmission fluid temperature (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 temperature or TFT voltage drop in and out of range? 
    1. 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 temperature or TFT voltage drop in and out of range, INSPECT for intermittent concern in the internal/external harness, sensor or connector.

    2. NO  : Go to  B3.
  3. B3 ELECTRICAL SIGNAL CHECK 
    • Key in ON position.
    • Remove transmission fluid pan.
    • Visually inspect the lead frame and connectors for damage.
      • Fig 1: Measuring Voltage With Positive Lead To Positive TFT At Sensor Pin & Negative Lead To A Good Ground
      GF0003442Courtesy of FORD MOTOR CO.
    • Measure the voltage with the positive lead to positive TFT at sensor pin and negative lead to a good ground.
    • Is any voltage present? 
    1. YES  : Go to  B4.
    2. NO  : CHECK for open or short circuit in vehicle harness, internal harness or a PCM concern.
  4. B4 CHECK THE RESISTANCE OF THE TFT SENSOR 
    • Disconnect: Transmission Harness
      • Fig 2: Checking Resistance Of TFT Sensor
      GF0003443Courtesy of FORD MOTOR CO.
    • Measure the resistance between the positive TFT and negative TFT pins at transmission connector, using the following:
      TRANSMISSION FLUID TEMPERATURE (TFT)

      °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
    • Is the resistance correct? 
    1. YES  : REFER to Diagnosis By Symptom  to diagnose an overheating concern.
    2. NO  : INSTALL a new internal harness (sensor is part of harness).
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