Diagnostic Aids

WARNING: This page is about a different car, the 1995 Ford Ranger. However, it is still accessible from the selected car via links, so may be relevant.

Perform this test when instructed during QUICK TEST or if directed by other test procedures. This test is used to diagnose the following:

Wiring harness circuits (TFT SIG and SIG RTN).
Faulty TFT sensor.
Faulty Powertrain Control Module (PCM).

Fig 1: Transmission Test Circuit & Connector Terminal ID (Ranger)

Fig 2: TP Sensor Wiring Harness Connector Terminal ID (Ranger)

TFT SENSOR SPECIFICATIONS

Temperature °F (°C)

⁽¹⁾ Volts

⁽¹⁾ Ohms

32 (0)

3.88

96,255

59 (15)

3.32

46,883

104 (40)

2.15

16,043

158 (70)

1.03

5270

185 (85)

0.61

3215

194 (90)

0.60

2750

⁽¹⁾	Value may vary by 15 percent.

1) DTC P0712

This code indicates that self-test has detected TFT sensor circuit input below specification. Possible causes for this code are as follows:

Fluid level out of specification.
Short circuit in wiring harness.
Faulty TFT sensor.
Faulty Powertrain Control Module (PCM).

Turn ignition off. Disconnect transmission wiring harness connector. Perform KOEO and KOER self-test. If DTC P0713 is present, replace TFT sensor. If DTC P0713 is not present, go to next step.

2) Check VREF At TP Sensor

Turn ignition off. Leave transmission connector disconnected. Disconnect TP sensor wiring harness connector. Turn ignition on. Measure voltage between SIG RTN and VREF terminals at connector. If voltage is 4-6 volts, go to next step. If voltage is not 4-6 volts, go to CIRCUIT TEST C.

3) Check For Short In TFT Circuit

Leave ignition off and transmission connector disconnected. Disconnect PCM 104-pin connector. Inspect pins for damage and repair if necessary. Install EEC-V Breakout Box (014-00950), leaving PCM disconnected. Measure resistance between test pins No. 37 (TFT) and test pins No. 91 (SIG RTN), 51 and 103 (PWR GND). If any resistance measurement is 10,000 ohms or less, repair short circuit and repeat QUICK TEST. If any resistance measurement is more than 10,000 ohms, replace PCM and repeat QUICK TEST.

NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 3) to step 10). No test procedures have been omitted.

10) DTC P0713

This code indicates that self-test has detected TFT sensor circuit input above specification. Possible causes for this code are as follows:

Fluid level out of specification.
Short between TFT and VPWR circuits.
Open in TFT or SIG RTN circuit.
Faulty TFT sensor.
Faulty Powertrain Control Module (PCM).

Turn ignition off. Disconnect transmission wiring harness connector. Install jumper wire between TFT and SIG RTN terminal of connector. Perform KOEO and KOER self-test. If DTC P0712 is present, replace TFT sensor. If DTC P0712 is not present, go to next step. If no codes are present, go to step 12).

11) Check Circuit Continuity

Leave ignition off and transmission wiring harness connector disconnected. Disconnect PCM 104-pin connector. Inspect pins for damage and repair if necessary. Install EEC-V Breakout Box (014-00950), leaving PCM disconnected. Measure resistance between test pin No. 37 (TFT) at breakout box and TFT terminal at transmission wiring harness connector. Measure resistance between test pin No. 91 (SIG RTN) at breakout box and SIG RTN terminal at transmission wiring harness connector. If each resistance measurement is less than 5 ohms, go to next step. If either resistance measurement is 5 ohms or more, repair open circuit and repeat QUICK TEST.

12) Check TFT Circuit Short To Power

Leave transmission wiring harness connector disconnected. Turn ignition on. Measure voltage between test pin No. 37 (TFT) and test pins No. 77 and 103 (PWR GND) at breakout box. If voltage is 2 volts or more, repair short to power in TFT circuit and repeat QUICK TEST. If voltage is less than 2 volts, replace PCM and repeat QUICK TEST.

NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 12) to step 20). No test procedures have been omitted.

20) DTC P1711

This code indicates that self-test has detected TFT sensor circuit input was out of range specification. Possible causes for this code are as follows:

Fluid level out of specification.
Fluid not at operating temperature.
Faulty TFT sensor.
Faulty Powertrain Control Module (PCM).

Ensure transmission fluid temperature is at least 50°F (10°C). Perform KOEO and KOER self-test. If DTC P1711 is present, go to next step. If DTC P1711 is not present, testing is complete.

21) Check VREF At TP Sensor

Turn ignition off. Disconnect TP sensor wiring harness connector. Turn ignition on. Measure voltage between SIG RTN and VREF terminals at connecter. If voltage is 4-6 volts, go to next step. If voltage is not 4-6 volts, go to CIRCUIT TEST C.

22) Check TFT Sensor Integrity

Warm transmission to normal operating temperature. Turn ignition off. Disconnect PCM 104-pin connector. Inspect pins for damage and repair if necessary. Install EEC-V Breakout Box (014-00950). Connect PCM to breakout box. Turn ignition on. Measure and record resistance between test pin No. 37 and 91 at breakout box. As transmission cools, verify resistance increases as specified. See TFT SENSOR SPECIFICATIONS table. If resistance does not change as specified, replace TFT sensor. If resistance changes as specified, replace PCM and repeat QUICK TEST.

NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 22) to step 90). No test procedures have been omitted.

90) Continuous Memory DTC P0712

This code indicates that self-test has detected TFT sensor circuit input below specification. Possible causes for this code are as follows:

Fluid level out of specification.
Short circuit in wiring harness.
Faulty TFT sensor.
Faulty Powertrain Control Module (PCM).

Turn ignition off. Connect scan tester to DLC. Using scan tester, access TFT PID. If TFT PID is 0.5 volt or more, go to next step. If TFT PID is less than 0.5 volt, return to step 1).

91) Wiggle Test TFT Sensor Circuits

Turn ignition off. Leave scan tester connected to DLC with TFT PIDs accessed. While shaking and bending TFT sensor wiring harness, observe TFT PID for indication of fault. A fault will be indicated by a sudden change in PID voltage. If fault is indicated, isolate and repair as necessary. If fault is not indicated, problem cannot be duplicated or identified at this time. Testing is complete.

NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 91) to step 100). No test procedures have been omitted.

100) Continuous Memory DTC P0713

This code indicates that self-test has detected TFT sensor circuit input above specification. Possible causes for this code are as follows:

Fluid level out of specification.
Short between TFT and VPWR circuits.
Open in TFT or SIG RTN circuit.
Faulty TFT sensor.
Faulty Powertrain Control Module (PCM).

Turn ignition off. Connect scan tester to DLC. Using scan tester, access TFT PID. If TFT PID is 4.8 volts or less, go to next step. If TFT PID is more than 4.8 volts, return to step 10).

101) Wiggle Test TFT Sensor Circuits

NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 101) to step 110). No test procedures have been omitted.

110) Continuous Memory DTC P1783

This code indicates that transmission has overheated. Possible causes for this code are as follows:

Incorrect transmission fluid level.
Faulty transmission cooling system.
Excessive load hauling.
Faulty transmission connector.

Turn ignition off. Disconnect transmission wiring harness connector. Perform KOEO self-test. If DTC P1783 is present, repair cause of transmission overheating as necessary. If DTC P1783 is not present, testing is complete.