Pinpoint Test B : Transmission Fluid Temperature (TFT) Sensor

WARNING: This page is about a different variant/trim than selected.

Refer to Transmission Controls - 8F35 for schematic and connector information.

Normal Operation and Fault Conditions

The TFT sensor is a dual range negative temperature coefficient thermistor, a non-linear resistor where resistance decreases as the temperature increases. The dual range arrangement allows for more accurate reading at cold temperatures. The TFT is in contact with transmission fluid in the main control valve body. The TFT signal is tested for voltage short to ground, open circuit, and coherency.

DTC Fault Trigger Conditions

DTC	Description	Fault Trigger Condition
PCM P0710:00	Transmission Fluid Temperature Sensor "A" Circuit: No Sub Type Information	This DTC sets if the fault was not present long enough for the TCM to determine a more specific fault. If a more specific DTCs such as P0712 or P0713 are set resolve them first.
PCM P0711:00	Transmission Fluid Temperature Sensor "A" Circuit Range/Performance: No Sub Type Information	This DTC sets if the TCM detects no change (failed to change by at least 8 degrees F) in the TFT sensor when the vehicle was driven enough that TFT should have changed.
PCM P0712:00	Transmission Fluid Temperature Sensor "A" Circuit Low: No Sub Type Information	This DTC sets if the TCM detects a short to ground in the TFT circuitry.
PCM P0713:00	Transmission Fluid Temperature Sensor "A" Circuit High: No Sub Type Information	This DTC sets if the TCM detects an open in the TFT circuitry.
PCM P1711:00	Transmission Fluid Temperature Sensor Out Of Self Test Range: No Sub Type Information	This DTC sets if the PCM the TFT sensor voltage was in range but the indicated value was outside the expected range for self test.

Possible Sources

Connectors damaged or pushed-out terminals, corrosion, loose wires and missing or damaged seals
TFT sensor
Transmission internal wiring harness frame
PCM

B1 CHECK TFT SIGNAL INPUT CIRCUIT FOR VOLTAGE

Ignition OFF.

Disconnect Transmission Vehicle Harness C1575.

Ignition ON.

NOTE: This pinpoint test is written to diagnose current DTCs retrieved during the KOEO or KOER test. Faults that only set a CMDTC may not be identified during this test.

Measure:

Positive Lead	Measurement / Action	Negative Lead
C1575-7	Courtesy of FORD MOTOR COMPANY	Ground

Is the voltage between 4.8 and 5.1 volts?

Yes

GO to B4

GO to B2

B2 CHECK TFT VOLTAGE CIRCUIT FOR AN OPEN

Ignition OFF.

Disconnect PCM C1551T.

Measure:

Positive Lead	Measurement / Action	Negative Lead
C1575-7	Courtesy of FORD MOTOR COMPANY	C1551T-42

Is the resistance less than 3 ohms?

Yes

GO to B3

No	REPAIR the open circuit.

B3 CHECK TFT VOLTAGE CIRCUIT FOR A SHORT TO GROUND

Measure:

Positive Lead	Measurement / Action	Negative Lead
C1575-7	Courtesy of FORD MOTOR COMPANY	Ground

Is the resistance greater than 10, 000 ohms?

Yes	Refer to PCM Guided Routine .

No	REPAIR the circuit.

B4 CHECK TFT SIGNAL RETURN CIRCUIT FOR AN OPEN

NOTE: TFT and the A clutch, B clutch sensor share a common signal return circuit. Concurrent circuit faults for both sensors are most likely due to a fault in the signal return circuit.

Ignition OFF.

Disconnect PCM C1551T.

Measure:

Positive Lead	Measurement / Action	Negative Lead
C1575-14	Courtesy of FORD MOTOR COMPANY	C1551T-7

Is the resistance less than 3 ohms?

Yes

GO to B5

No	REPAIR the circuit.

B5 CHECK TFT SIGNAL RETURN CIRCUIT FOR A SHORT TO GROUND

Measure:

Positive Lead	Measurement / Action	Negative Lead
C1575-14	Courtesy of FORD MOTOR COMPANY	Ground

Is the resistance greater than 10, 000 ohms?

Yes

GO to B6

No	REPAIR the circuit.

B6 CHECK INTERNAL WIRING HARNESS FOR AN OPEN

Remove the main control cover. REFER to: Main Control Cover .

Disconnect TFT Sensor C1842.

Measure:

Positive Lead	Measurement / Action	Negative Lead
Courtesy of FORD MOTOR COMPANY Transmission harness connector, component side, pin 7	Courtesy of FORD MOTOR COMPANY	C1842-1
Courtesy of FORD MOTOR COMPANY Transmission harness connector, component side, pin 14	Courtesy of FORD MOTOR COMPANY	C1842-2

Are the resistances less than 3 ohms?

Yes

GO to B7

No	INSTALL a new internal wiring harness. REFER to: Main Control Valve Body .

B7 CHECK INTERNAL WIRING HARNESS FOR A SHORT TO GROUND

Measure:

Positive Lead	Measurement / Action	Negative Lead
Courtesy of FORD MOTOR COMPANY Transmission harness connector, component side, pin 7	Courtesy of FORD MOTOR COMPANY	Ground
Courtesy of FORD MOTOR COMPANY Transmission harness connector, component side, pin 14	Courtesy of FORD MOTOR COMPANY	Ground

Are the resistances greater than 10, 000 ohms?

Yes

GO to B8

No	INSTALL a new internal wiring harness. REFER to: Main Control Valve Body .

B8 CHECK TFT SENSOR RESISTANCE

Measure and record the resistance of the TFT sensor.

Compare the measured resistance to the current temperature of the TFT sensor using the following chart.

deg.C	deg.F	Resistance (ohms)
-50 to -40	-58 to -40	41k-97k
-39 to -20	-39 to -4	14k-52k
-19 to -1	-3 to 31	5.5k-17k
0 to 20	32 to 68	2.3k-6.4k
21 to 40	69 to 104	1.1k-2.7k
41 to 70	105 to 158	0.4k-1.3k
71 to 90	159 to 194	236-445
91 to 110	195 to 230	140-247
111 to 130	231 to 266	87-145
131 to 150	267 to 302	55-90

Does the resistance match the specification on the temperature chart?

Yes	The TFT is working correctly at this time. To diagnose an overheating concern, REFER to: Transmission Cooling .

No	INSTALL a new TFT sensor. REFER to: Main Control Valve Body .