Pinpoint Test B: Transmission Fluid Temperature (TFT) Sensor

• Key in OFF position.
• Shift selector lever to position P.
• Check to make sure the transaxle harness connector is fully seated, terminals 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? 

Yes  : REMAIN in PID/Data Control. GO to  B2.

No  : REPEAT procedure to enter PID. If vehicle did not enter PID, REFER to the INTRODUCTION - GASOLINE for diagnosis of PCM.

• While monitoring the TFT PIDs, carry out the following test: If transaxle is cold, run transaxle to warm it up. If transaxle is warm, allow transaxle to cool down.
• Do the TFT PIDs increase as the transaxle is warmed up or decrease as the transaxle is cooled or does the TFT or TFTV drop in and out of range? 

Yes  : If the TFT PIDs increase as the transaxle is warmed or decrease as the transaxle 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 transaxle overheating. If the TFT drops in and out of range, INSPECT for intermittent concern in the internal/external harness, sensor or connector.

No  : GO to  B3.

• Disconnect: Transaxle Vehicle Harness Connector.
• Visually inspect all wires and connectors for damage.
• Measure the voltage between transaxle vehicle harness connector pin 5, harness side and ground; and between transaxle vehicle harness connector pin 4, harness side and ground.
  Fig 1: Checking Powertrain Control Module And Vehicle Harness For Power

  Courtesy of FORD MOTOR CO.
• Is voltage present? 

Yes  : GO to  B4.

No  : GO to  B5.

• Disconnect: PCM Connector.
• Measure the voltage between transaxle vehicle harness connector pin 5, harness side and ground; and between transaxle vehicle harness connector pin 4, harness side and ground.
  Fig 2: Checking Vehicle Harness For Short To Power

  Courtesy of FORD MOTOR CO.
• Is voltage present? 

Yes  : REPAIR the circuit. TEST the system for normal operation.

No  : INSTALL a new PCM. TEST the system for normal operation.

• Connect: PCM Connector.
• Measure the resistance between transaxle vehicle harness connector pin 5, harness side and ground; and between transaxle vehicle harness connector pin 4, harness side and ground.
  Fig 3: Checking Powertrain Control Module And Vehicle Harness For Ground

  Courtesy of FORD MOTOR CO.
• Is the resistance greater than 10,000 ohms? 

Yes  : GO to  B7.

No  : GO to  B6.

• Disconnect: PCM Connector.
• Measure the resistance between transaxle vehicle harness connector pin 5, harness side and ground; and between transaxle vehicle harness connector pin 4, harness side and ground.
  Fig 4: Checking Vehicle Harness For Short To Ground

  Courtesy of FORD MOTOR CO.
• Is the resistance greater than 10,000 ohms? 

Yes  : INSTALL a new PCM. TEST the system for normal operation.

No  : REPAIR the circuit. TEST the system for normal operation.

• Measure the resistance between transaxle vehicle harness connector pin 5, harness side and PCM connector pin 29, harness side.
  Fig 5: Checking Vehicle Harness For Open (1 Of 2)

  Courtesy of FORD MOTOR CO.
• Measure the resistance between transaxle vehicle harness connector pin 4, harness side and PCM connector pin 41, harness side.
  Fig 6: Checking Vehicle Harness For Open (2 Of 2)

  Courtesy of FORD MOTOR CO.
• Is the resistance less than 5 ohms? 

Yes  : GO to  B8.

No  : REPAIR the circuit. TEST the system for normal operation.

• Measure the resistance between transaxle vehicle harness connector pin 5 (component side, transaxle internal harness), and ground; and between transaxle vehicle harness connector pin 4 (component side, transaxle internal harness), and ground.
  Fig 7: Checking Transaxle Internal Harness For An Short To Ground

  Courtesy of FORD MOTOR CO.
• Is the resistance greater than 10,000 ohms? 

Yes  : GO to  B9.

No  : INSTALL a new transaxle internal harness. TEST the system for normal operation.

• Measure the resistance between transaxle vehicle harness connector pin 5 (component side, transaxle internal harness), and transmission fluid temperature sensor internal harness connector pin 5; and between transaxle vehicle harness connector pin 4 (component side, transaxle internal harness), and transmission fluid temperature sensor internal harness connector pin 4.
  Fig 8: Checking Transaxle Internal Harness For Open

  Courtesy of FORD MOTOR CO.
• Is the resistance less than 5 ohms? 

Yes  : GO to  B10.

No  : INSTALL a new transaxle internal harness. TEST the system for normal operation.

• Measure the resistance between transaxle vehicle harness connector pin 5 (component side, transaxle internal harness), and transaxle vehicle harness connector pin 4 (component side, transaxle internal harness).
• Record the resistance.
• Resistance should be approximately in the following ranges:
  • -20°C (-4°F) - 236-317 K ohms.
  • 0°C (32°F) - 83.2-107 K ohms.
  • 20°C (68°F) - 33.5-41.2 K ohms.
  • 40°C (104°F) - 14.6-17.6 K ohms.
  • 60°C (140°F) - 7.08-8.01 K ohms.
  • 80°C (176°F) - 3.61-4.06 K ohms.
  • 100°C (212°F) - 1.96-2.20 K ohms.
  • 120°C (248°F) - 1.13-1.25 K ohms.
  • 130°C (266°F) - 0.87-0.96 K ohms.
• Is the resistance in the range? 

Yes  : REFER to DIAGNOSIS BY SYMPTOM  to diagnose an overheating concern.

No  : INSTALL a new TFT sensor. TEST the system for normal operation.