Diagnostic Aids

Perform this test only when directed by QUICK TEST. To prevent replacing good components, be aware following non-EEC areas may be at fault:

Transmission fluid level.
Transmission fluid temperature.
Ambient temperature.

This test is intended to diagnose:

TOT sensor.
Wiring harness circuits TOT and SIG RTN.
Faulty ECA.

Fig 1: Trans. Oil Temperature (TOT) Sensor Ckt. (AXOD-E - Continental, Sable & Taurus)

Fig 2: Trans. Oil Temperature (TOT) Sensor Ckt. (AOD-E - Crown Victoria, Grand Marquis & Town Car)

Fig 3: Trans. Oil Temperature (TOT) Sensor Ckt. (Escort & Tracer)

TOT SENSOR (AXOD-E) SPECIFICATIONS

Temperature: °F (°C)

⁽¹⁾ Volts

⁽¹⁾ Ohms

32 (0)

3.88

96,255

41 (5)

3.71

75,201

50 (10)

3.53

59,175

59 (15)

3.32

46,883

68 (20)

3.10

37,387

77 (25)

2.86

30,000

86 (30)

2.62

24,215

95 (35)

2.38

19,657

104 (40)

2.15

16,043

113 (45)

1.92

13,161

122 (50)

1.71

10,050

131 (55)

1.51

8990

140 (60)

1.33

7487

149 (65)

1.17

6265

158 (70)

1.03

5260

167 (75)

0.90

4450

176 (80)

0.78

3775

185 (85)

0.69

3215

194 (90)

0.60

2750

200 (95)

0.52

2361

⁽¹⁾	Value may vary by 15 percent.

TOT SENSOR (4EAT) SPECIFICATIONS

Temperature: °F (°C)

⁽¹⁾ Volts

⁽¹⁾ Ohms

32 (0)

4.8

52,000

68 (20)

4.6

23,000

104 (40)

4.3

11,000

140 (60)

3.7

5600

212 (100)

2.4

1711

266 (130)

1.5

860

⁽¹⁾	Value may vary by 15 percent.

1) KOEO Code 26/636 KOEO Code 26/636 indicate TOT sensor is out of self-test range. Possible causes for these faults are:

Transmission fluid incorrect temperature.
Incorrect sensor resistance.
Faulty ECA.

Ensure transmission fluid temperature is more than 50°F (10°C). Repeat QUICK TEST . If Code 26/636 is present, go to step 2). If Code 26/636 is not present, test is complete.

2) Check VREF At Throttle Position Sensor (TPS) Turn ignition off. Disconnect TPS sensor wiring harness connector. Disconnect 60-pin ECA connector. Inspect terminals, and repair if damaged. Install EEC-IV Breakout Box (T83L-50-EEC-IV). Connect ECA to breakout box. Turn ignition on. Measure voltage between VREF and SIG RTN terminals at TPS wiring harness connector. If voltage is 4-6 volts, go to step 3). If voltage is not 4-6 volts, go to CIRCUIT TEST C.

3) Check TOT Sensor Resistance Turn key off. With breakout box installed and processor disconnected, turn key on, engine off. Verify that oil pan is warm to the touch.

If it is too hot to touch: measure and record TOT sensor resistance between TOT test pin and Test Pin 46 at breakout box, then let transmission cool down and repeat measurement. The last resistance measurement should be greater than the first.
If it is too cold: measure and record TOT sensor resistance between TOT test pin and Test Pin 46 at breakout box, then reconnect processor and drive vehicle for short time to elevate oil temperature. Disconnect processor and repeat measurements at breakout box. The last resistance should be less than the first.

Did resistance measurement differ and was last measurement within specifications? See appropriate TOT SENSOR SPECIFICATIONS TABLE at beginning of test above. If yes, replace processor, remove breakout box and rerun QUICK TEST . If no, remove breakout box. Reconnect processor. On Escort/Tracer go to step 25. For all other models fault is in transmission.

10) KOEO Code 56 Or 637 KOEO Code 56 and 637 indicate TOT sensor output exceeds self-test maximum voltage. Possible causes for these faults are:

Transmission fluid temperature incorrect.
Open wiring harness circuit.
Faulty ECA.

Turn ignition off. Disconnect TOT wiring harness connector. Inspect terminals, and repair if damaged. Connect jumper wire between TOT and SIG RTN terminals. Perform KOER SELF-TEST . If Code 66/638 is present, go to step 25) (Escort and Tracer) or fault is in transmission (except Escort and Tracer). If Code 66/638 is not present, go to step 11).

11) Check TOT & SIG RTN Circuit Continuity Turn ignition off. Leave TOT sensor disconnected. Disconnect 60-pin ECA connector. Inspect terminals, and repair if damaged. Install EEC-IV Breakout Box(T83L-50-EEC-IV), leaving ECA disconnected. Measure resistance between TOT circuit at TOT wiring harness connector and TOT test pin at breakout box. Measure resistance between SIG RTN circuit at TOT wiring harness connector and TOT test pin at breakout box. If either resistance is more than 5 ohms, repair open circuit and repeat QUICK TEST . If each resistance is 5 ohms or less, go to step 12).

12) Check TOT Sensor For Short To VPWR Turn ignition off. Leave ECA and TOT sensor disconnected. Measure resistance between TOT test pin and test pins No. 37 and 57 at breakout box. If resistance is more than 10,000 ohms, replace ECA and repeat QUICK TEST . If resistance is 10,000 ohms or less, repair short circuit 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) KOEO Code 66 Or 638 KOEO Code 66 and 638 indicate TOT sensor output is lower than self-test minimum voltage. Possible causes for these faults are:

Damaged TOT sensor.
Shorted wiring harness circuit.
Faulty ECA.

Turn ignition off. Disconnect transmission wiring harness connector. Inspect terminals, and repair if damaged. Perform KOEO SELF-TEST . If Code 56 or 637 is present, go to step 25) (Escort and Tracer) or fault is in transmission (except Escort and Tracer). If Code 66/638 is not present, go to step 21).

21) Check VREF At Throttle Position Sensor (TPS) Turn ignition off. Disconnect TPS sensor wiring harness connector. Disconnect 60-pin ECA connector. Inspect terminals, and repair if damaged. Install EEC-IV Breakout Box (T83L-50-EEC-IV). Connect ECA to breakout box. Turn ignition on. Measure voltage between VREF and SIG RTN terminals at TPS wiring harness connector. See Fig 4 . If voltage is 4-6 volts, go to step 22). If voltage is not 4-6 volts, go to CIRCUIT TEST C.

Fig 4: Throttle Position Sensor (TPS) Connector Terminal ID

22) Check TOT Sensor Resistance Turn ignition off. Disconnect ECA from breakout box. Measure resistance between TOT test pin at breakout box and test pins No. 40, 46 and 60. If resistance is more than 10,000 ohms, replace ECA and repeat QUICK TEST . If resistance is 10,000 ohms or less, repair short circuit and repeat QUICK TEST.

25) Check Transmission Wiring Harness Turn ignition off. Check transmission internal and external wiring and connectors for damage and corrosion. Repair or replace if necessary. If wiring is okay, replace TOT sensor and repeat QUICK TEST .

NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 25) to step 90). No test procedures have been omitted.

90) Continuous Memory Code 637/638 Continuous Memory Code 637/638 indicates TOT sensor output is lower than during previous 80 warm-up cycles; a fault has been detected in TOT circuit. Possible causes for these faults are:

Intermittent fault in TOT sensor.
Intermittent short or open in wiring harness.

Turn ignition off. Disconnect 60-pin ECA connector. Inspect terminals, and repair if damaged. Install EEC-IV Breakout Box (T83L-50-EEC-IV). Connect ECA to breakout box. Connect DVOM between test pins No. 2 and 46 at breakout box. Turn ignition on. Shake and bend TOT and SIG RTN wires between transmission and ECA. Voltage should remain stable or change gradually. If voltage drops or surges abruptly, fault in circuit is indicated. If fault is indicated, isolate and repair as necessary. If no faults are found, problem cannot be located at this time.