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Home >> Ford >> 2009 >> Flex Limited, FWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 1959 (Automatic Transmission - Automatic Transaxle/Transmission) >> Diagnosis And Testing >> Pinpoint Tests - OSC Equipped Vehicle >> Pinpoint Tests >> Pinpoint Test B: TFT Sensor

Pinpoint Test B: TFT Sensor

WARNING: This page is about a different car, the 2010 Lincoln MKX and 2010 Ford Edge. However, it is still accessible from the selected car via links, so may be relevant.
NOTE: Check the transmission fluid level prior to performing this pinpoint test. An over full condition will cause the transaxle to over heat. For additional information on fluid level checking, refer to the TRANSMISSION FLUID LEVEL CHECK  in Preliminary Inspection  .
NOTE: Refer to the Transaxle Vehicle Harness Connector illustration within the TRANSAXLE CONNECTOR LAYOUTS PROCEDURE .
  1. B1 ELECTRONIC DIAGNOSTICS 
    • Check the transmission fluid level.
    • Check to make sure transaxle vehicle harness connector C168 is fully seated, terminals are fully engaged in connector and in good condition before proceeding.
    • Have the above items been checked? 
    • Yes:  GO to B2  .
    • No:  CARRY OUT checks. CLEAR the DTCs. REPEAT the Self Test.
  2. B2 CHECK THE TFT SENSOR CIRCUITS FOR AN OPEN 
    • Ignition OFF.
    • Disconnect: Transaxle Vehicle Harness C168.
    • Disconnect: PCM Transaxle C175T.
    • Use a mirror to inspect both ends of the connector for damage or pushed-out pins, corrosion, loose wires and missing or damaged seals.
    • Measure the resistance between PCM transaxle C175T-20, circuit VET27 (BN/YE) and transaxle vehicle harness C168-2, circuit VET27 (BN/YE).
      Fig 1: Measuring Resistance Between PCM Transaxle C175T-20, Circuit VET27 (BN/YE) And Transaxle Vehicle Harness C168-2
      G06502319Courtesy of FORD MOTOR CO.
    • Measure the resistance between PCM transaxle C175T-43, circuit RE406 (GY/VT) and transaxle vehicle harness C168-3, circuit RE406 (GY/VT).
      Fig 2: Measuring Resistance Between PCM Transaxle C175T-43, Circuit RE406 (GY/VT) And Transaxle Vehicle Harness C168-3
      G06067633Courtesy of FORD MOTOR CO.
    • Is the resistance less than 5 ohms? 
    • Yes:  GO to B3  .
    • No:  REPAIR the circuit (s) for an open. CONNECT all components. TEST the system for normal operation.
  3. B3 CHECK THE TFT SENSOR CIRCUITS FOR A SHORT TO GROUND 
    • Measure the resistance between transaxle vehicle harness C168-2, circuit VET27 (BN/YE) and ground.
      Fig 3: Measuring Resistance Between Transaxle Vehicle Harness C168-2, Circuit VET27 (BN/YE) And Ground
      G06067634Courtesy of FORD MOTOR CO.
    • Measure the resistance between transaxle vehicle harness C168-3, circuit RE406 (GY/VT) and ground.
      Fig 4: Measuring Resistance Between Transaxle Vehicle Harness C168-3, Circuit RE406 (GY/VT) And Ground
      G06067635Courtesy of FORD MOTOR CO.
    • Are the resistances greater than 10,000 ohms? 
    • Yes:  GO to B4  .
    • No:  REPAIR the circuit (s) for a short to ground. CONNECT all components. TEST the system for normal operation.
  4. B4 CHECK THE TFT CIRCUITS FOR A SHORT TO VPWR 
    • Ignition ON.
    • Measure the voltage between transaxle vehicle harness C168-2, circuit VET27 (BN/YE) and ground.
      Fig 5: Measuring Voltage Between Transaxle Vehicle Harness C168-2, Circuit VET27 (BN/YE) And Ground
      G06067636Courtesy of FORD MOTOR CO.
    • Measure the voltage between transaxle vehicle harness C168-3, circuit RE406 (GY/VT) and ground.
      Fig 6: Measuring Voltage Between Transaxle Vehicle Harness C168-3, Circuit RE406 (GY/VT) And Ground
      G06502324Courtesy of FORD MOTOR CO.
    • Is any voltage present? 
    • Yes:  REPAIR the circuit (s) for a short to voltage. CONNECT all components. TEST the system for normal operation.
    • No:  GO to B5  .
  5. B5 CHECK THE RESISTANCE OF THE TFT SENSORS/HARNESS 
    • Ignition OFF.
    • Connect: Transaxle Vehicle Harness C168.
    • TEST 1  .
    • Measure and record the resistance between PCM transaxle C175T-20, circuit VET27 (BN/YE) and C175T-43, circuit RE406 (GY/VT).
      Fig 7: Measuring Record Resistance Between PCM Transaxle C175T-20 And C175T-43, Circuit RE406 (GY/VT)
      G06282572Courtesy of FORD MOTOR CO.
    • Compare the resistance value to the following table ranges:
      TRANSMISSION FLUID TEMPERATURE

      °C °F Resistance (Ohms)
      -40 to -20 -40 to -4 1,076K-269K
      -19 to -1 -3 to 31 309K-91K
      0-20 32-68 104K-35K
      21-40 69-104 40K-15K
      41-70 105-158 17K-4.9K
      71-90 159-194 5.6K-2.5K
      91-110 195-230 3.0K-1.4K
      111-130 231-266 1.7K-0.8K
      131-150 267-302 0.97K-0.56K
    • TEST 2  .
    • Check for intermittent short or open.
    • If the resistance was between 0.8k and 100k ohms, carry out the following test. If the transaxle is warm, allow it to cool. Check the TFT  sensor resistance again. Compare the resistance with the initial resistance. The resistance should decrease if the transaxle was heated and should increase if the transaxle was allowed to cool. If correct, then change in the resistance occurs, repeat On-Board Diagnostic (OBD).
    • Is the resistance in the range? 
    • Yes:  INSTALL a new PCM. CONNECT all components. TEST the system for normal operation.
    • No:  INSTALL a new solenoid body. REFER to SOLENOID BODY ASSEMBLY . RECONNECT all components. TEST the system for normal operation.
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