Pinpoint Test B: TFT Sensor

WARNING: This page is about a different car, the 2014 Ford F-150. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: Refer to the TRANSMISSION VEHICLE HARNESS CONNECTOR illustration within the TRANSMISSION CONNECTOR LAYOUTS procedure.

NOTE: Refer to the TRANSMISSION LEADFRAME CONNECTOR illustration within the TRANSMISSION CONNECTOR LAYOUTS procedure.

NOTE: If the scan tool is unable to access the transmission PIDs, refer to ENGINE CONTROLS - INTRODUCTION (EXCEPT DIESEL & HYBRID) (SECTION 0) .

NOTE: Read and record all DTCs.

B1 CHECK TFT INPUT SIGNAL
- Ignition OFF.
- Disconnect: Transmission Vehicle Harness C1575 .
- Inspect the connector for damaged or pushed out terminals, corrosion, loose wires and missing or damaged seals.
- Connect the scan tool.
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: TFT PIDs: TFT and TFTV.
Does the TFT PID display -40°C (-40°F) and the TFTV PID display 4.96 to 5.10 volts?
- Yes : GO to B2 .
- No : REPAIR vehicle harness circuit VET27 (BN/YE) for a short to ground. CLEAR the DTCs. TEST the system for normal operation.
B2 CHECK TFT SIGNAL INPUT CIRCUIT FOR VOLTAGE
- Measure the voltage between the transmission vehicle harness C1575-6 , circuit VET27 (BN/YE), harness side and ground.
  
  Fig 1: Measuring Voltage Between Transmission Vehicle Harness C1575-6, Circuit VET27 (BN/YE) And Ground
  Courtesy of FORD MOTOR CO.
Is the voltage between 4.8 and 5.1 volts?
- Yes : GO to B3 .
- No : INSPECT and REPAIR transmission vehicle harness circuit VET27 (BN/YE) for an open. If an open circuit is not found, REPLACE the PCM, REFER to POWERTRAIN CONTROL MODULE (PCM) . PROGRAM the PCM with the latest calibration level. PERFORM the Solenoid Body Strategy Data Download procedure. REFER to SOLENOID BODY STRATEGY . TEST the system for normal operation.
B3 CHECK TFT SIGNAL RETURN CIRCUIT
- Connect a fused jumper between the transmission vehicle harness C1575-5 and C1575-6 , harness side.
  
  Fig 2: Connecting Fused Jumper Between Transmission Vehicle Harness C1575-5 And C1575-6
  Courtesy of FORD MOTOR CO.
Does the TFT PID display 190°-195°C (374°-383°F) and the TFTV PID display 0 volts?
- Yes : GO to B4 .
- No : INSPECT and REPAIR the transmission vehicle harness signal return circuit for an open. If an open circuit is not found, REPLACE the PCM, REFER to POWERTRAIN CONTROL MODULE (PCM) . PROGRAM the PCM with the latest calibration level. PERFORM the Solenoid Body Strategy Data Download procedure. REFER to SOLENOID BODY STRATEGY . TEST the system for normal operation.

B4 CHECK TFT SENSOR RESISTANCE

Measure the resistance between the transmission molded leadframe C1575-5 and C1575-6 , component side using the following chart.

RESISTANCE REFERENCE

°C	°F	Resistance
-40 to -20	-40 to -4	967K-284K
-19 to -1	-3 to 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

Fig 3: Measuring Resistance Between Transmission Molded Leadframe C1575-5 And C1575-6

Courtesy of FORD MOTOR CO.

Does the temperature to resistance specifications match?

Yes : REFER to DIAGNOSIS BY SYMPTOM to diagnose an overheating concern.
No : INSPECT and CLEAN the TFT sensor on the molded leadframe for metallic contamination. INSTALL a new molded leadframe if no debris was found, REFER to SHIFT SOLENOIDS (SS) . CLEAR the DTCs. TEST the system for normal operation.