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Home >> Mercury >> 2008 >> Milan Base, 2.3 Z, Automatic >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 2 (Automatic Transaxle/Transmission - AISIN Aw21) >> Diagnostic Tests >> Pinpoint Tests - Non 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 variant/trim than selected.
  1. B1 ELECTRONIC DIAGNOSTICS 
    • Connect the diagnostic tool.
    • Check to make sure the transaxle harness connector is fully seated, pins are fully engaged in connector and in good condition before proceeding.
    • Key in ON position.
    • Select Diagnostic Data Link.
    • Select Transmission Control Module (TCM).
    • Select PID/TFT.
    • Enter the following diagnostic mode on the diagnostic tool: PIDs; TFT
    • Does the vehicle enter PID/TFT? 
    1. YES  : Go to  B2.
    2. NO  : REPEAT procedure to enter PID. If vehicle did not enter PID, REFER to the Introduction - Gasoline Engines article.
  2. B2 TEMPERATURE SIGNAL CHECK 
    • Key in ON position.
    • Select Diagnostic Data Link.
    • Select TCM.
    • Select PID/TFT.
    • Enter the following diagnostic mode on the diagnostic tool: PIDs; TFT
    • Monitor the TFT PID. The temperature value should be within -55°C to 175°C (-65°F to 347°F).
    • Is the Transmission Fluid Temperature (TFT) within specified range? 
    1. YES  : Go to  B3.
    2. NO  : Go to  B4.
  3. B3 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, decrease as the transmission is cooled and does the TFT stay within the specified range? 
    1. YES  : INSTALL a new TCM and REFLASH to the latest level calibration. CLEAR all DTCs. ROAD TEST to verify concern is not present. Concern could be intermittent. If concern is still present or reappears, go to  B4 .
    2. NO  : Go to  B4.
  4. B4 SIGNAL RESISTANCE 
    • Remove the TCM.
    • Inspect both sides of the TCM for damaged or pushed-out pins, corrosion or damaged seals.
      • Fig 1: Checking Signal Resistance
      GF0017758Courtesy of FORD MOTOR CO.
    • Measure the resistance between pins 7 and 8 at the transaxle bulkhead electrical connector. Refer to the following table.
      TRANSMISSION FLUID TEMPERATURE (TFT) SENSOR RESISTANCE

      °C °F Resistance (Ohms)
      10 50 6.445
      25 77 3.5
      110 230 0.247
    • Record the resistance.
    • Is the resistance within range? 
    1. YES  : Go to  B5.
    2. NO  : INSTALL a new internal harness and TFT assembly.
  5. B5 SHORT TO GROUND 
      Fig 2: Measuring Resistance Between Pin 7 & Ground At Transaxle Bulkhead Electrical Connector
      GF0017759Courtesy of FORD MOTOR CO.
    • Measure the resistance between pin 7 and ground at the transaxle bulkhead electrical connector.
      • Fig 3: Measuring Resistance Between Pin 8 & Ground At Transaxle Bulkhead Electrical Connector
      GF0017760Courtesy of FORD MOTOR CO.
    • Measure the resistance between pin 8 and ground at the transaxle bulkhead electrical connector.
    • Record the resistances.
    • Are the resistances greater than 10,000 ohms? 
    1. YES  : INSTALL a new TCM and REFLASH to the latest level calibration.
    2. NO  : INSTALL a new internal harness and TFT assembly.
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