Test TC - E4OD Automatic Transmission: Notes

NOTE: You should perform this test when Codes 26/636, 47/633, 56/637, 66/638, 67/634 & 654, 91/621, 92/622, 93/626, 94/627, 98/998 and 99/624 are displayed during KOEO SELF-TEST, Codes 26/636, and 65/632 are displayed during KOER SELF-TEST, or Codes 29/452, 49/617, 56/637, 59/618, 62/628, 66/638, 69/619 and 99/624 are displayed during CONTINUOUS MONITOR MODE testing or when directed here during DIAGNOSIS BY SYMPTOM tests. This circuit test is intended to diagnose only the following: harness circuits, CCC, CCS, 4WD LOW, EPC, CILY, OCS, SS1, SS2, SIGRTN, TOT, MLP, VPWR and ECA.

The Transmission Solenoid Assembly (7G391) and Manual Lever Position (MLP) sensor (7F293) are not diagnosed in this circuit test as they are not controlled by the ECA.

Fig 1: RPM Sensor Circuit

Fig 2: 4WD Low & Overdrive Cancel Harness Schematic

1) Code 67/634: Check Resistance Through MLP Sensor Code 67/634 indicates that total resistance in the MLP sensor is out of Self-Test range when the selector lever is in "P" (correct range is 3770-4607 ohms). Possible causes for this fault are: faulty MLP sensor, open or shorted harness, faulty ECA.

Turn key off and wait 10 seconds. Disconnect ECA 60-pin connector and inspect for corroded or damaged pins. Service or repair as necessary. Install breakout box, leaving ECA disconnected. Set DVOM on 10 k/ohm scale. With KOEO, measure resistance between test pins No. 30 and 46 at the breakout box while moving the selector from "P" to "L" and back to "P". Record specifications and compare to specification table. If resistance is within specification, go to step 3). If resistance is not as specified, go to next step.

Code 654: indicates that the selector lever was not in the "P" during Self Test. The possible causes are are faulty or misadjusted MLP sensor, Open or short harness, or Faulty processor.

MLP RESISTANCE SPECIFICATIONS

Gear Position	Minimum Ohms	Maximum Ohms
"P"	3770	4607
"R"	1304	1593
"N"	660	807
"D"	361	442
"2"	190	232
"1"	78	95

2) Checking Continuity of MLP Harness Ensure key is off and MLP sensor is disconnected from harness. Use a mirror to inspect ends of transmission harness connector at MLP sensor for damage or corrosion. Repair as necessary. Install breakout box, leaving ECA disconnected. Set DVOM on 200-ohm scale. Measure resistance between test pin No. 30 at the breakout box and corresponding pin at the MLP sensor vehicle harness connector. Measure resistance between test pin No. 46 at the breakout box and corresponding pin at the MLP sensor vehicle harness connector. If both resistances are less than 5 ohms, go to next step. If resistances are not as specified, repair open circuit, remove breakout box, reconnect components and rerun QUICK TEST.

3) Check MLP Harness For Short To Power Or Ground Turn key off. Ensure MLP sensor harness is disconnected. Install breakout box leaving ECA disconnected. Set DVOM on 200-k/ohm scale. Measure resistance between test pin No. 30 and test pins No. 37 and 57 at the breakout box. Measure resistance between test pin No. 30 and test pins No. 40, 46 and 60 at the breakout box. Measure resistance between test pin No. 30 at the breakout box and chassis ground. If all resistances are greater than 10 k/ohms, go to next step. If resistances are less than 10 k/ohms, repair short circuits, remove breakout box, reconnect components and rerun QUICK TEST.

TEST PIN WIRE COLOR IDENTIFICATION

Application		Wire Color
Test Pins 35 & 37/57
7.3L Diesel		Yellow/White
5.8L & 7.5L		Red or Red/White

4) Checking ECA Output Voltage Ensure key is off. Disconnect MLP sensor from harness. Install breakout box and connect ECA. With KOEO, set DVOM on 20-volt scale. Measure voltage between test pins No. 30 and 46 at the breakout box. If voltage is 4.75-5.25 volts, service or adjust MLP sensor. If voltage is not as specified, replace ECA, reconnect components and rerun QUICK TEST.

5) Code 47/633, 65/632 or 97/631: Verify Self-Test Mode Code 47/633 indicates 4WD LOW selector lever is not in 2WD or 4WD High position during KOEO Self-Test. This condition may be accompanied by an early shift in the 4WD High range. Code 65/632 indicates that Overdrive Cancel Switch (OCS) is not cycled between the engine I.D. code and "Goose Test" in the KOER Self-Test. Code 97/631 indicates an Overdrive Cancel Light (OCL) fault during KOER Self-Test. Possible causes for this fault are: faulty 4WD LOW switch, faulty OCS switch, burned out bulb, open harness, shorted harness or faulty ECA. Rerun QUICK TEST. If none of the above codes are present, fault cannot be duplicated at this time, testing is complete. If Code 97/631 is present, go to step 7). If any other codes are present, go to next step.

6) Cycle 4WD LOW Or Overdrive Cancel Switch Circuit Turn key off and wait 10 seconds. Disconnect ECA 60-pin connector and inspect for corroded or damaged pins. Service or repair as necessary. Install breakout box, leaving ECA disconnected. With KOEO, set DVOM on 20-volt scale.