Pinpoint Test B: Transmission Fluid Temperature (TFT) Sensor

WARNING: This page is about a different car, the 2004 Mercury Mountaineer and 2004 Ford Explorer. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: Refer to the TRANSMISSION VEHICLE HARNESS Connector illustration preceding these pinpoint tests.

B1 ELECTRONIC DIAGNOSTICS
- Key in OFF position.
- Select PARK.
- Check to make sure the transmission harness connector is fully seated, terminals are fully engaged in connector and in good condition before proceeding.
- Connect the diagnostic tool.
- Key in ON position.
- Enter the following diagnostic mode on the diagnostic tool: Diagnostic Data Link.
- Enter the following diagnostic mode on the diagnostic tool: PCM.
- Enter the following diagnostic mode on the diagnostic tool: PID/Data Monitor and Record.
- Enter the following diagnostic mode on the diagnostic 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 INTRODUCTION - CNG, FLEX-FUEL & GASOLINE for diagnosis of PCM and NGS.
B2 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 or decrease as the transmission is cooled or does the TFT or TFTV drop in and out of range?
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 or TFTV drop in and out of range, INSPECT for intermittent concern in the internal/external harness, sensor or connector.

No

GO to B3.
B3 ELECTRICAL SIGNAL CHECK
- Disconnect: Transmission Harness Connector.
- Visually inspect all wires and connectors for damage.
- Measure the voltage between pin 2 harness side and ground.
  
  Fig 1: Measuring Voltage Between Pin 2 Harness Side And Ground
  Courtesy of FORD MOTOR CO.
- Is the voltage between 4.5 and 5.5 volts?
Yes

GO to B4.

No

REPAIR the circuit. TEST the system for normal operation.

B4 CHECK RESISTANCE OF TFT SENSOR

Measure the resistance between pin 2 and 12 at the solenoid body connector.

Fig 2: Measuring Resistance Between Pin 2 And 12 At Solenoid Body Connector
Courtesy of FORD MOTOR CO.
Record the resistance.

Resistance should be approximately in the following ranges:

Transmission Fluid Temperature

RESISTANCE RANGE ACCORDING TO TRANSMISSION FLUID TEMPERATURE

°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 in the range?

Yes

refer to DIAGNOSIS BY SYMPTOM to diagnose an overheating concern.

INSTALL a new solenoid body assembly.