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Diagnostic Aids

Perform this test only when directed by QUICK TEST. Ensure all basic transmission mechanical faults are serviced before continuing with this test. This test is intended to diagnose only the following circuits or systems:

Fig 1: AXODE Transaxle Circuits (Sable & Taurus)
G91G09225
Fig 2: Temperature Sensor Values
G91A09227
3.0L SPFI-MA (AXODE) TEST PIN WIRE COLOR IDENTIFICATION

Application Wire Color
Pin 5 (TSS) Gray/Black
Pin 30 (MLPS) Light Blue
Pin 37 (VPWR) Red
Pin 38 (EPC) White/Yellow
Pin 40 (PWR GND) Black/Light Green
Pin 46 (SIG RTN) Gray/Red
Pin 47 (TP) Gray/White
Pin 49 (TOT) Orange/Black
Pin 51 (SS-1) Orange/Yellow
Pin 52 (SS-2) Pink/Orange
Pin 53 (LUS) Tan/White
Pin 55 (SS-3) White/Red
Pin 57 (VPWR) Red
Pin 60 (PWR GND) Black/Light Green


Voltage values are calculated for VREF = 5 volts. These values may vary 15 percent due to sensor and VREF variations. Transmission oil temperature must be a minimum of 50°F before measuring resistance of transmission oil temperature sensor.

NOTE: There is a break in the step numbering sequence at this point, skipping steps 1) through 9). Break is due to previous chart references to these testing procedures. No test procedures have been omitted.

10) Codes 621, 622, 629, 641 & 652: Circuit Identification  Codes 621, 622, 629, 641 and 652 indicate a solenoid did not properly change states when commanded by ECA. Possible causes for these faults are as follows:

Match code to appropriate solenoid in chart below. If any of the listed codes are present, go to next step. If none of the listed codes are present, rerun QUICK TEST and check for other codes.

Fig 1: Matching Code With Solenoid
G91C09228

11) Enter Output State Check  Use only VOM or DVOM for this test. Disconnect speed control servo electrical connector (if equipped). Set VOM or DVOM to 20-volt scale. Connect negative lead of meter to STO circuit at self-test connector and positive lead of meter to positive battery terminal. Install jumper wire between STI circuit and SIGNAL RETURN at self-test connector.

Enter KOEO SELF-TEST until Continuous Memory Codes are displayed. DVOM will indicate less than one volt when test is complete. When less than one volt is displayed, depress and release throttle. If voltage increases, remain in OUTPUT STATE CHECK and go to next step. If voltage does not increase, depress throttle to Wide Open Throttle (WOT) and release. If STO voltage does not go high then low, leave equipment in place and go to TEST QC, step 1).

12) Check Solenoid Electrical Operation  Turn ignition on, leaving engine off. Disconnect transmission bulkhead connector of appropriate solenoid (see schematic at beginning of this circuit test). Using a mirror, inspect both ends of connector for damaged or pushed out pins, corrosion, loose wires or other damage. Repair as necessary. Set DVOM to 20-volt scale. Connect DVOM positive lead to solenoid VPWR circuit and negative lead to ECA signal output pin at transmission vehicle harness connector. Refer to MATCHING CODE WITH SOLENOID chart in step 10). While observing DVOM, depress and release throttle several times to cycle solenoid on and off. If output voltage changes greater than .5 volt, reconnect bulkhead connector and diagnose transmission. If output voltage changes less than .5 volt, reconnect bulkhead connector; remove jumper wire and go to next step.

13) Check Solenoid Resistance  Turn ignition off and wait 10 seconds. Disconnect ECA 60-pin connector. Inspect connector for damaged pins, corrosion, or loose wires; repair as necessary. Install breakout box and leave ECA disconnected. Set DVOM to 200-ohm scale. Measure resistance between test pin No. 37/57 and ECA output test pin at breakout box. Refer to MATCHING CODE WITH SOLENOID chart in step 10). If resistance is 15-32 ohms, go to step 15). If resistance is NOT 15-32 ohms, go to next step.

14) Check Continuity Of Solenoid Signal And VPWR Harness Circuits  Turn ignition off and wait 10 seconds. With breakout box installed and ECA disconnected, disconnect transmission bulkhead connector at solenoid. Set DVOM to 200-ohm scale. Measure resistance between ECA signal output test pin at breakout box and solenoid signal output pin at transmission vehicle harness connector. Refer to MATCHING CODE WITH SOLENOID chart in step 10). Measure resistance between test pin No. 37/57 and VPWR pin at transmission vehicle harness connector (see schematic at beginning of this circuit test). If each resistance is less than 5 ohms, go to next step. If resistance is greater than 5 ohms, repair open circuit. Remove breakout box, reconnect all components and rerun QUICK TEST.

15) Check Solenoid Harness Circuits For Shorts To Power Or Ground  Turn ignition off and wait 10 seconds. Install breakout box and leave ECA disconnected. Disconnect transmission bulkhead solenoid connector. Set DVOM to 200-k/ohm scale. Measure resistance between ECA signal output pin and test pin No. 37/57. Refer to MATCHING CODE WITH SOLENOID chart in step 10). Measure resistance between ECA signal output pin and test pins No. 40, 60 and 46 at breakout box and chassis ground. If each resistance is greater than 10 k/ohms, go to next step. If resistance is less than 10 k/ohms, repair short circuit. Remove breakout box, reconnect all components and rerun QUICK TEST.

16) Check Solenoid VPWR Supplied By ECA  Turn ignition off and wait 10 seconds. Install breakout box and connect ECA to breakout box. Disconnect transmission bulkhead connector. Set DVOM to 20-volt scale. Turn ignition on and measure voltage between test pin No. 37/57 at transmission vehicle harness connector and chassis ground or negative battery terminal. If voltage is greater than 10.5 volts, go to next step. If voltage is less than 10.5 volts, replace ECA. Remove breakout box, reconnect all components and rerun QUICK TEST.

17) Check Solenoid Driver Signal  This step requires use of a non-powered 12-volt test light. Turn ignition off and wait 10 seconds. With breakout box installed and ECA connected, disconnect transmission bulkhead connector. Connect test light between test pin No. 37/57 and ECA signal output pin at breakout box. Refer to MATCHING CODE WITH SOLENOID chart in step 10). Enter KOEO SELF-TEST. If test light flashes momentarily then stays off, problem is within transmission. Diagnose transmission. If test light does not flash momentarily then stay off, replace ECA. Remove breakout box, reconnect all components and rerun QUICK TEST.

NOTE: There is a break in the step numbering sequence at this point, skipping from step 17) to step 20). Break is due to previous chart references to these testing procedures. No test procedures have been omitted.

20) Codes 624 And 625: Check Continuity Of EPC Solenoid Signal And VPWR Harness Circuits  Code 624 indicates current flow through EPC solenoid is higher than normal. High current (near one amp.) can cause line pressure to be low in the wrong drive mode.

Code 625 indicates current flow through EPC solenoid is lower than normal. Low current (near zero amp.) can cause line pressure to be 90 PSI in the wrong drive mode. Possible causes for these faults are as follows:

Turn ignition off and wait 10 seconds. Disconnect ECA 60-pin connector. Inspect connector for damaged pins, corrosion, or loose wires; repair as necessary. Install breakout box and connect ECA to breakout box. Disconnect EPC transmission bulkhead connector. Set DVOM to 200-ohm scale. Measure resistance between test pin No. 38 and EPC signal output pin at transmission vehicle harness connector. Measure resistance between test pin No. 37/57 and VPWR circuit at transmission vehicle harness connector. If resistance is less than 5 ohms, go to next step. If resistance is greater than 5 ohms, repair open circuit. Remove breakout box, reconnect all components and rerun QUICK TEST.

21) Check EPC Signal Harness Circuit For Short To VPWR And Short To Ground  - Turn ignition off and wait 10 seconds. Install breakout box, leaving ECA disconnected. Disconnect EPC transmission bulkhead connector. Set DVOM to 200-k/ohm scale. Measure resistance between test pins No. 38 and 37/57. Measure resistance between test pin No. 38 and test pins No. 40, 60 and 46. If each resistance is greater than 10 k/ohms, reconnect EPC connector and go to next step. If resistance is less than 10 k/ohms, repair short circuit. Remove breakout box, reconnect all components and rerun QUICK TEST.

22) Check Solenoid Resistance  Turn ignition off and wait 10 seconds. Install breakout box, leaving ECA disconnected. Ensure EPC solenoid is connected. Set DVOM to 200-ohm scale. Measure resistance between test pins No. 37/57 and 38 (EPC signal to ECA pin) at breakout box. If resistance is 3-7 ohms, go to next step. If resistance is NOT 3-7 ohms, diagnose transmission (problem is internal in transmission).

23) Check VPWR Of EPC Solenoid Supplied By ECA  Turn ignition off and wait 10 seconds. Install breakout box and connect ECA to breakout box. Disconnect EPC transmission bulkhead connector. Set DVOM to 20-volt scale. With Key On Engine Off (KOEO), measure voltage between VPWR circuit at EPC solenoid transmission vehicle harness connector and chassis ground. If voltage is greater than 10.5 volts, go to next step. If voltage is less than 10.5 volts, replace ECA. Remove breakout box, reconnect all components and rerun QUICK TEST.

24) Check Output Driver Signal  This step requires use of a 12-volt non-powered test light. Turn ignition off and wait 10 seconds. Install breakout box and connect ECA to breakout box. Disconnect EPC transmission bulkhead connector. Connect test light between test pins No. 37/57 and 38 (EPC signal output pin). If test light flashes momentarily and then remains off, diagnose transmission (problem is internal in transmission). If test light does not function as described, replace ECA. Remove breakout box, reconnect all components and rerun QUICK TEST.

NOTE: There is a break in the step numbering sequence at this point, skipping from step 24) to step 30). Break is due to previous chart references to these testing procedures. No test procedures have been omitted.

30) Code 636: Increase Transmission Oil Temperature  Code 636 indicates output of transmission oil temperature sensor was out of self-test range. Sensor output shows failure occurring at either the low or high end of acceptable range. The correct range of measurement is .21-3.50 volts. Possible causes for this fault are as follows:

Drive vehicle through normal city traffic for 30 minutes to bring transmission to a temperature of at least 50°F. Rerun QUICK TEST. If code 636 is present, go to next step. If code 636 is not present, transmission oil temperature sensor is okay. Service other codes displayed.

31) Check For VREF At Throttle Position Sensor (TPS)  Turn ignition off and wait 10 seconds. Disconnect ECA 60-pin connector. Inspect connector for damaged pins, corrosion, or loose wires; repair as necessary. Install breakout box, connect ECA to breakout box and disconnect TPS. Set DVOM to 20-volt scale. With KOEO, measure voltage between VREF and SIG RTN at TPS vehicle harness connector. Refer to schematic at beginning of TEST DH. If voltage is 4-6 volts, reconnect TPS and go to next step. If voltage is NOT 4-6 volts, go to TEST C, step 1).

32) Check Transmission Oil Temperature (TOT) Sensor Resistance Change As Transmission Oil Temperature Is Varied  Turn ignition off and wait 10 seconds. Install breakout box and leave ECA disconnected. Set DVOM to 200-ohm scale. Ensure transmission oil pan is warm to touch. Turn ignition on with engine off. If transmission is too hot to touch, measure and record resistance between test pins No. 49 and 46. Let transmission cool down and repeat measurement. The last measurement should be greater than the first.

If transmission is cold, measure and record resistance between test pins No. 49 and 46. Reconnect ECA and drive vehicle a short time to increase transmission oil temperature. Disconnect ECA and repeat measurement at breakout box. The last measurement should be less than the first. If resistance measurements are different and the last measurement is within specifications, replace ECA. See TEMPERATURE SENSOR VALUES chart at beginning of this circuit test. Remove breakout box and rerun QUICK TEST. If measurements do not differ and last measurement is not within specification, remove breakout box; reconnect all components and service or replace TOT sensor.

NOTE: There is a break in the step numbering sequence at this point, skipping from step 32) to step 40). Break is due to previous chart references to these testing procedures. No test procedures have been omitted.

40) Code 637: Induce Opposite Code  Code 637 indicates transmission oil temperature (TOT) sensor output is greater than self-test maximum value of 4.8 volts. Possible causes for this fault are as follows:

Disconnect transmission bulkhead connector at TOT sensor. Inspect for damaged or pushed-out pins, corrosion or other damage; repair as necessary. Connect jumper wire from TOT SIGNAL (test pin No. 49) to TOT SIG RTN (test pin No. 46) at transmission vehicle harness connector. Run KOEO SELF-TEST. If code 638 is present, remove jumper wire and service or replace TOT sensor. If code 638 is not present, remove jumper wire and go to next step.

41) Check Continuity Of Transmission Oil Temperature Signal And Signal Return Harness Circuits  Turn ignition off and wait 10 seconds. Disconnect transmission bulkhead connector. Disconnect ECA 60-pin connector. Inspect connector for damaged pins, corrosion, or loose wires; repair as necessary. Install breakout box, leaving ECA disconnected. Set DVOM to 200-ohm scale. Measure resistance between TOT SIGNAL pin at transmission vehicle harness connector and test pin No. 49.

Measure resistance between TOT SIG RTN pin at transmission vehicle harness connector and test pin No. 46. If each resistance is less than 5 ohms, replace ECA. Remove breakout box, reconnect all components and rerun QUICK TEST. If resistance is greater than 5 ohms, repair open circuit. Remove breakout box, reconnect all components and rerun QUICK TEST.

NOTE: There is a break in the step numbering sequence at this point, skipping from step 41) to step 50). Break is due to previous chart references to these testing procedures. No test procedures have been omitted.

50) Code 638: Induce Opposite Code  Code 638 indicates TOT sensor output is less than the allowed self-test minimum value of .15 volt. Possible caused for this code are as follows:

Turn ignition off and wait 10 seconds. Disconnect transmission bulkhead connector at TOT sensor. Inspect connector for damaged pins, corrosion, or loose wires; repair as necessary. Run KOEO SELF-TEST. If code 637 is present, service or replace TOT sensor. If code 637 is not present, go to next step.

51) Check VREF At Throttle Position Sensor  Turn ignition off and wait 10 seconds. Disconnect ECA 60-pin connector. Inspect connector for damaged pins, corrosion, or loose wires; repair as necessary. Install breakout box, connect ECA to breakout box and disconnect TPS. Set DVOM to 20-volt scale. With KOEO, measure voltage between VREF and SIG RTN at TPS vehicle harness connector. Refer to schematic at beginning of TEST DH. If voltage is 4-6 volts, reconnect TPS and go to next step. If voltage is NOT 4-6 volts, go to TEST C, step 1).

52) Check TOT Signal Circuit For Short To Ground  Turn ignition off and wait 10 seconds. Disconnect transmission bulkhead connector. Install breakout box, leaving ECA disconnected. Set DVOM to 200-k/ohm scale. Measure resistance between test pin No. 49 and test pins No. 40, 60 and 46. If each resistance is greater than 10 k/ohms, replace ECA. Remove breakout box, reconnect all components and rerun QUICK TEST. If resistance is less than 10 k/ohms, repair short circuit. Remove breakout box, reconnect all components and rerun QUICK TEST.

NOTE: There is a break in the step numbering sequence at this point, skipping from step 52) to step 60). Break is due to previous chart references to these testing procedures. No test procedures have been omitted.

60) Continuous Memory Code 639: Complete TSS Drive Cycle And Verify Code  Code 639 indicates that sometime during the last 80 warm-up cycles, ECA detected an error in Turbine Speed Sensor (TSS) output signal. Possible causes for this fault are as follows:

Perform turbine speed sensor drive cycle as follows: Record and clear continuous memory codes. Warm engine to operating temperature. Place gear selector in LOW position and accelerate heavily to 35 MPH. Coast down to idle and stop vehicle. Turn engine off.

After drive cycle is completed, run KOEO SELF-TEST and record Continuous Memory Codes displayed. If Code 639 repeated, go to next step. If Code 639 is not displayed, fault cannot be duplicated at this time. Service any other codes present at this time.

61) Check Continuity Of Turbine Speed Sensor Harness Circuits  Turn ignition off and wait 10 seconds. Disconnect ECA 60-pin connector. Inspect connector for damaged pins, corrosion, or loose wires; repair as necessary. Install breakout box, leaving ECA disconnected. Disconnect turbine speed sensor. Set DVOM to 200-ohm scale. Measure resistance between test pin No. 5 and TSS signal circuit at sensor vehicle harness connector. Measure resistance between test pin No. 46 and SIG RTN circuit at TSS vehicle harness connector. If each resistance is less than 5 ohms, go to next step. If resistance is greater than 5 ohms, repair open circuit. Remove breakout box, reconnect all components and rerun QUICK TEST.

62) Check TSS Harness Circuits For Shorts To Power Or Ground  Turn ignition off and wait 10 seconds. Disconnect TSS. Install breakout box, leaving ECA disconnected. Set DVOM to 200-k/ohm scale. Measure resistance between test pins No. 5 and 37/57. Measure resistance between test pin No. 5 and test pins No. 40/60 and 46. If each resistance is greater than 5 ohms, go to next step. If resistance is less than 5 ohms, repair short circuit. Remove breakout box, reconnect all components and rerun QUICK TEST.

63) Check TSS Resistance  Turn ignition off and wait 10 seconds. Disconnect TSS. Set DVOM to 200-ohm scale. Measure resistance of TSS. If resistance is 108-146 ohms, remove breakout box; reconnect all components and repeat step 60) to verify elimination of code. If resistance is NOT 108-146 ohms, replace TSS. Remove breakout box, reconnect all components and repeat step 60) to verify elimination of code.

NOTE: There is a break in the step numbering sequence at this point, skipping from step 63) to step 70). Break is due to previous chart references to these testing procedures. No test procedures have been omitted.

70) Engine Running Code 639: Check Turbine Speed Sensor (TSS) Harness Continuity  Code 639 indicates frequency or voltage of TSS is out of engine running self-test range. Possible cause are as follows:

Turn ignition off and wait 10 seconds. Disconnect TSS. Disconnect ECA 60-pin connector. Inspect connector for damaged pins, corrosion, or loose wires; repair as necessary. Install breakout box, leaving ECA disconnected. Set DVOM to 200-ohm scale. Measure resistance between test pin No. 5 and TSS signal circuit at TSS vehicle harness connector. Measure resistance between test pin No. 46 and TSS SIG RTN circuit at TSS vehicle harness connector. If each resistance is less than 5 ohms, go to next step. If resistance is greater than 5 ohms, repair open circuit. Remove breakout box, reconnect all components and rerun QUICK TEST.

71) Check TSS Harness For Short To Power Or Ground  Turn ignition off and wait 10 seconds. Disconnect TSS. Install breakout box, leaving ECA disconnected. Set DVOM to 200-k/ohm scale. Measure resistance between test pins No. 5 and 37/57. Measure resistance between test pin No. 5 and test pins No. 40/60 and 46. If each resistance is greater than 500 ohms, remove breakout box, reconnect ECA and go to next step. If resistance is less than 500 ohms, repair short circuit. Remove breakout box, reconnect all components and rerun QUICK TEST.

72) Check TSS resistance  Turn ignition off and wait 10 seconds. Disconnect TSS. Set DVOM to 200-ohm scale. Measure resistance of TSS. If resistance is 108-146 ohms, remove breakout box; reconnect all components and rerun QUICK TEST. If resistance is NOT 108-146 ohms, replace TSS. Remove breakout box, reconnect all components and rerun QUICK TEST.

NOTE: There is a break in the step numbering sequence at this point, skipping from step 72) to step 80). Break is due to previous chart references to these testing procedures. No test procedures have been omitted.

80) Code 522: Check Resistance Of Manual Lever Position (MLP) Sensor  Code 522 indicates resistance of MLP sensor is out of self-test range when gear selector lever is in PARK position. Correct resistance range for this sensor is 3770-4607 ohms. Possible causes for this fault are as follows:

Turn ignition off and wait 10 seconds. Disconnect TSS. Disconnect ECA 60-pin connector. Inspect connector for damaged pins, corrosion, or loose wires; repair as necessary. Install breakout box, leaving ECA disconnected. Set DVOM to 200-k/ohm scale. Unlock steering wheel and ensure ignition is off. Measure resistance between test pins No. 30 and 46 in each gear selector position. If each resistance is within specifications, go to step 82). See MANUAL LEVER POSITION SENSOR SPECIFICATIONS chart. If resistance is not within specifications, go to next step.

MANUAL LEVER POSITION SENSOR SPECIFICATIONS

Shift Position Resistance Minimum Ohms Resistance Maximum Ohms
Park 3770 4607
Reverse 1304 1593
Neutral 660 807
Overdrive 361 442
Drive 190 232
1st 78 95

81) Check Continuity Of Manual Lever Position (MLP) Sensor Harness Circuits  Turn ignition on, leaving engine off. Disconnect MLP sensor. Using a mirror, inspect both ends of connector for damaged or pushed-out pins, corrosion, loose wires or other damage. Repair as necessary. Set DVOM to 200-ohm scale. Install breakout box, leaving ECA disconnected. Measure resistance between test pin No. 30 and MLP signal circuit at MLP sensor vehicle harness connector. Measure resistance between test pin No. 46 and SIG RTN circuit at MLP sensor vehicle harness connector. If each resistance is less than 5 ohms, go to next step. If resistance is greater than 5 ohms, repair open circuit. Remove breakout box, reconnect all components and rerun QUICK TEST.

82) Check Manual Lever Position (MLP) Sensor Circuit For Short To Ground Or Power  Turn ignition off and wait 10 seconds. Disconnect MLP sensor. Install breakout box and leave ECA disconnected. Set DVOM to 200-k/ohm scale. Measure resistance between test pins No. 30 and 37/57. Measure resistance between test pin No. 30 and test pins No. 40/60 and 46. Measure resistance between test pin No. 30 and chassis ground. If each resistance is greater than 10 k/ohms, go to next step. If resistance is less than 10 k/ohms, repair short circuit. Remove breakout box, reconnect all components and rerun QUICK TEST.

83) Check ECA Output Voltage  Turn ignition off and wait 10 seconds. Disconnect MLP sensor. Install breakout box and connect ECA to breakout box. Set DVOM to 20-volt scale. With KOEO, measure voltage between test pins No. 30 and 46. If voltage is 4.75-5.25 volts, service or replace MLP sensor. If voltage is NOT 4.75-5.25 volts, replace ECA. Remove breakout box, reconnect all components and rerun QUICK TEST.

NOTE: There is a break in the step numbering sequence at this point, skipping from step 83) to step 90). Break is due to previous chart references to these testing procedures. No test procedures have been omitted.

90) Prepare For AXODE Drive Cycle And Check For Solenoid Error Codes  Ensure all components are connected properly and transmission fluid level is correct. Ensure engine is at normal operating temperature. Run KOEO SELF-TEST and record all Continuous Memory Codes displayed. If Continuous Memory Code 645, 646, 647 or 648 is displayed, go to step 97). If code is not displayed, go to next step.

91) AXODE Drive Cycle: Attempt To Verify MLP, TOT Or Solenoid Codes Received  Place gear selector in OVERDRIVE position. Drive vehicle in residential or city traffic. Accelerate and decelerate moderately using each shift range. Stop fully (do not "roll" stop) 20 seconds during drive cycle. Repeat drive cycle-stop road test 2 times then return to service bay.

Run KOEO SELF-TEST and record all Continuous Memory Codes. If Code 111 (pass code) is displayed, fault cannot be duplicated at this time; testing is complete. If Code 624, 625, 628, 629, 634, 637, 638, 649 or 651 is displayed, go to next step.

NOTE: There is a break in the step numbering sequence at this point, skipping from step 91) to step 93). Break is due to previous chart references to these testing procedures. No test procedures have been omitted.

93) Enter KOEO Continuous Monitor Mode: Check Circuit  Enter KOEO wiggle test. See CONTINUOUS MONITOR MODE (WIGGLE TEST) under QUICK TEST near the beginning of this article. Observe VOM, DVOM or "Scan" Tool for indication of fault while performing the following for the codes received:

For Code 634 (manual lever position sensor error code), lightly tap on manual lever position sensor to simulate road shock. Wiggle connector at manual lever position sensor.

For codes 624, 625, 628, 629, 637, 638, 649 and 651, wiggle transmission bulkhead connectors. If a fault is indicated, disconnect and inspect connectors. If terminals are okay, repair/replace suspected sensor, solenoid or transmission. If fault is not indicated, go to next step.

94) Check EEC-IV Vehicle Harness  Remain in KOEO wiggle test. Observe VOM, DVOM or "Scan" Tool for indication of fault while performing the following: Grasp harness closest to connector of transmission solenoid or sensor. Wiggle, shake and/or bend small section of EEC-IV vehicle harness, working forward to dash panel, ECA and back toward transmission connector. If fault is indicated, isolate and repair as necessary. Clear codes and rerun QUICK TEST. If fault is not indicated, go to next step.

95) Check ECA And Harness Connectors  Turn ignition off and wait 10 seconds. Disconnect ECA 60-pin connector. Inspect connector for damaged pins, corrosion, or loose wires; repair as necessary. Clear codes and rerun QUICK TEST. If connector and terminals are okay, fault cannot be duplicated at this time. Clear codes and rerun QUICK TEST.

96) Continuous Memory Codes 645, 646, 647 And 648 Fault Isolation  Code 645 indicates first gear failure. Code 646 indicates second gear failure. Code 647 indicates third gear failure. Code 648 indicates fourth gear failure. Possible causes for these codes are as follows:

Rerun KOEO SELF-TEST. If codes other than Codes 645, 646, 647 and 648 are generated, service those codes first and rerun QUICK TEST. If other codes are not present. go to next step.

97) Enter KOEO Continuous Monitor Mode: Check Circuits  Enter KOEO wiggle test. See CONTINUOUS MONITOR MODE (WIGGLE) under QUICK TEST near the beginning of this article. Observe VOM, DVOM or "Scan" Tool for indication of fault while performing the following: Wiggle, shake and/or bend small section of EEC-IV vehicle harness, working toward dash panel, ECA and transmission bulkhead connector. If fault is indicated, isolate and repair as necessary. Clear codes and rerun QUICK TEST. If fault is not indicated, service or repair transmission as necessary.

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