Transmission Fluid Temperature (TFT) Sensor

1994 PCED OBDI-A

SECTION 6A: EEC-IV Pinpoint Test
Procedures

TE: Transmission Fluid Temperature (TFT) Sensor
Introduction

TE: Pinpoint Tests

Note

You should enter this Pinpoint Test only when you have been directed here from Diagnostic Routines, Section 2A.

Remember

To prevent the replacement of good components, be aware that the following non-EEC areas may at fault:

Engine/transmission fluid levels
Engine/transmission operating temperature
Ambient temperature

This Pinpoint Test is intended to diagnose only the following:

TFT sensor
Harness circuits: TFT and SIG RTN
Powertrain Control Module (PCM) (12A650) or (12B565 on 7.3L Diesel)

Description

The Transmission Fluid Temperature (TFT) sensor is a thermistor that changes resistance in response to temperature. The TFT sensor resistance decreases as the surrounding fluid temperature increases. The resistance variation is converted into a voltage signal and sent to the PCM to give an indication of the transmission fluid temperature.

Pinpoint Test Schematics

Escort/Tracer (4EAT)

Probe (CD4E)

Taurus/Sable, Continental AX4S

Mustang, Thunderbird/Cougar, Crown Victoria/Grand Marquis, Town Car, E-Series (AODE/4R70W)

E-Series/F-Series/Bronco (E4OD)

Escort/Tracer (4EAT)

Note: Voltage and resistance values may vary ± 15%.

Temperature		TFT Sensor Values (4EAT)
°C	°F	VOLTS	K OHMS
-40	-40	4.97	325.50
0	32	4.82	52.00
20	68	4.61	23.00
40	104	4.26	11.00
60	140	3.74	5.60
100	212	2.40	1.71
130	266	1.5	0.86

All Others

Note: Voltage values are calculated for VREF = 5.0 volts: These values may vary 15 percent due to sensor and VREF variations. Transmission fluid temperature must be minimum of 10°C (50°F) before taking transmission fluid temperature sensor resistance measurements.

Temperature		TFT Sensor Values
°F	°C	Voltage (V)	Resistance (K ohms)
194	90	0.599	2.750
158	60	1.025	5.260
104	40	2.149	16.043
59	15	3.318	46.883
32	0	3.882	96.255

TE: Pinpoint Tests