Pinpoint Test B: Transmission Fluid Temperature (TFT) Sensor

WARNING: This page is about a different car, the 2006 Mercury Milan and 2006 Ford Fusion. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: Refer to Figure .

B1 ELECTRONIC DIAGNOSTIC SETUP
- Key in OFF position.
- Select PARK.
- 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.
- Enter the following diagnostic mode on the scan tool: Diagnostic Data Link.
- Enter the following diagnostic mode on the scan tool: PCM.
- Enter the following diagnostic mode on the scan tool: 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 article for diagnosis of PCM.
B2 WARM-UP/COOL-DOWN CYCLE VERIFICATION
- 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.
B3 CHECK TRANSMISSION CONTROL MODULE AND VEHICLE HARNESS FOR POWER
- Disconnect: Transaxle Vehicle Harness Connector C1534.
- 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 Transmission Control Module And Vehicle Harness For Power
  Courtesy of FORD MOTOR CO.
- Is voltage present?
Yes : GO to B4.

No : GO to B5.
B4 CHECK VEHICLE HARNESS FOR A SHORT TO POWER
- Disconnect: TCM Connector C2352b.
- 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 TCM. TEST the system for normal operation.
B5 CHECK TRANSMISSION CONTROL MODULE AND VEHICLE HARNESS FOR GROUND
- Connect: TCM Connector C2352b.
- 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 Transmission Control Module And Vehicle Harness For Ground
  Courtesy of FORD MOTOR CO.
- Are the resistances greater than 10,000 ohms?
Yes : GO to B7.

No : GO to B6.
B6 CHECK VEHICLE HARNESS FOR SHORT TO GROUND
- Disconnect: TCM Connector C2352b.
- 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.
- Are the resistances greater than 10,000 ohms?
Yes : INSTALL a new TCM. TEST the system for normal operation.

No : REPAIR the circuit. TEST the system for normal operation.
B7 CHECK VEHICLE HARNESS FOR AN OPEN
- Measure the resistance between transaxle vehicle harness connector C1534-5, harness side and TCM connector C2352b-6; and between transaxle vehicle harness connector C1534-4, harness side and TCM connector C2352b-5, harness side.
  
  Fig 5: Checking Vehicle Harness For An Open
  Courtesy of FORD MOTOR CO.
- Are the resistances less than 5 ohms?
Yes : GO to B8.

No : REPAIR the circuit. TEST the system for normal operation.
B8 CHECK THE TRANSAXLE INTERNAL HARNESS FOR A SHORT TO GROUND
- 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 6: Checking Transaxle Internal Harness For Short To Ground
  Courtesy of FORD MOTOR CO.
- Are the resistances greater than 10,000 ohms?
Yes : GO to B9

No : INSTALL a new transaxle internal harness. TEST the system for normal operation.
B9 CHECK RESISTANCE OF THE TFT SENSOR
- 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
- Are the resistances in the range?
Yes : REFER to DIAGNOSIS BY SYMPTOM to diagnose an overheating concern.

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