Pinpoint Test B: Transmission Fluid Temperature (TFT) Sensor

Refer to TRANSMISSION CONTROLS - 8F35 for schematic and connector information.

Normal Operation and Fault Conditions

The TFT sensor is a temperature dependent resistor that is in contact with transmission fluid in the transmission sump area. The PCM monitors the voltage across the TFT sensor, which changes as transmission fluid temperature varies. The PCM uses the TFT sensor signal as an input for its shifting strategy and TCC operation. The PCM also uses the TFT sensor signal for transmission fault detection and diagnostics.

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 CIRCUIT FOR VOLTAGE

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."

Ignition OFF.

Disconnect: Transmission Vehicle Harness C1520.

Inspect the connector for damaged or pushed out terminals, corrosion, loose wires and missing or damaged seals.

Ignition ON.

Measure:

Positive Lead	Measurement / Action	Negative Lead
C1520-2	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 C1915E.

Measure:

Positive Lead	Measurement / Action	Negative Lead
C1520-2	Courtesy of FORD MOTOR COMPANY	C1915E-93

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
C1520-2	Courtesy of FORD MOTOR COMPANY	Ground

Is the resistance greater than 10, 000 ohms?

Yes

Verify all PCM power circuits and fuses. DIAGNOSE all other VREF sensor faults, if present. If no other concerns are found, Refer to PCM GUIDED ROUTINE TESTING
PROGRAM the PCM to the latest calibration level. PERFORM the Solenoid Body Strategy Data Download procedure. REFER to: Transmission Strategy Download .

No	REPAIR the circuit.

B4 CHECK TFT SIGNAL RETURN CIRCUIT FOR AN OPEN

NOTE: TFT, TFPA, and TFPB share a common signal return circuit. Concurrent circuit faults for all 3 sensors are most likely due to a fault in the signal return circuit.

Ignition OFF.

Disconnect PCM C1915E.

Measure:

Positive Lead	Measurement / Action	Negative Lead
C1520-21	Courtesy of FORD MOTOR COMPANY	C1915E-57

Is the resistance less than 3 ohms?

Yes

GO to B5

No	REPAIR the open circuit.

B5 CHECK TFT SIGNAL RETURN CIRCUIT FOR A SHORT TO GROUND

Connect:

Positive Lead	Measurement / Action	Negative Lead
C1915E-57	Courtesy of FORD MOTOR COMPANY	Ground

Is the resistance greater than 10, 000 ohms?

Yes	The vehicle harness is OK. GO to B6

No	REPAIR the circuit.

B6 CHECK INTERNAL WIRING HARNESS FOR AN OPEN

Ignition OFF.

REMOVE 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 2	Courtesy of FORD MOTOR COMPANY	C1842-1
Courtesy of FORD MOTOR COMPANY Transmission harness connector, component side, pin 21	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: Transmission Internal Wiring Harness Frame .

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 2	Courtesy of FORD MOTOR COMPANY	Ground
Courtesy of FORD MOTOR COMPANY Transmission harness connector, component side, pin 21	Courtesy of FORD MOTOR COMPANY	Ground

Are the resistances greater than 10, 000 ohms?

Yes	The Transmission Internal Wiring Harness is OK. GO to B8

No	INSTALL a new internal wiring harness. REFER to: Transmission Internal Wiring Harness Frame .

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.

°C	°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 .