Test Fa - Neutral Drive Switch (NDS) A/C Input CKT

NOTE: Perform this test when Service Code 67 or 79 is displayed during QUICK TESTS or when directed here by other test procedures. This test is designed to diagnose the following:

A/C input to ECA
Clutch Engagement Switch (CES)
Neutral Clutch Switch (NCS)
Neutral Drive Switch (NDS)
Neutral Gear Switch (NGS)
ECA
Harness circuits (CES, NCS, NDS, NGS, ACC, ACCS & SIG RTN)

TEST PIN WIRE COLOR IDENTIFICATION

Application (Pin No.)		Wire Color
Pin 10, A/C Input
MA PFI		Green/Black
TBI		Black/Yellow
Pin 30, NDS
MA PFI		Brown/Yellow
TBI & PFI		Gray/Orange
Pin 46, SIG RTN
MA PFI		Light Green/Black
All Others		Black/White

1) Code 67: System Identification Code 67 indicates that during engine cranking or KOEO SELF-TEST, signal voltage was greater than specification at test pin No. 10 (A/C input) or test pin No. 30 (NDS). Possible causes for this fault are: A/C circuit shorted to power, Neutral clutch/drive circuits open, Neutral clutch/drive switch open, faulty ECA, or a starter relay disconnected during self-test. See TEST STEP APPLICATION REFERENCE to enter this test at the correct step.

TEST STEP APPLICATION REFERENCE

Engine/Trans Application		Go To Step Number
Manual Transmissions
TBI		10)
MA PFI & PFI		2)
Automatic Transmissions		13)

2) Checking Neutral Gear/Clutch Circuit Input Turn key off and wait 10 seconds. Ensure A/C control is in OFF position (if equipped). Disconnect ECA 60-pin connector. Inspect for and repair any damaged wiring. Install breakout box, leave ECA disconnected. Set DVOM on 200-ohm scale. Measure resistance between test pins No. 30 and 46 with transmission in Neutral and clutch pedal in the up position. Measure resistance with transmission in gear and clutch pedal depressed. If both resistances are less than 5 ohms, go to next step. If not, go to step 5.

Fig 1: Neutral Gear & Clutch Circuit Diagram
3) Check Neutral Gear/Clutch Switch Input Circuit Turn key off and wait 10 seconds. Install breakout box, leave ECA disconnected and set DVOM to 200-ohm scale. Measure resistance between test pins No. 30 and 46 with transmission in any gear and the clutch pedal in the UP position. If resistance is less than 5 ohms, on vehicles equipped with A/C, go to step 10. If not equipped with A/C, replace ECA and remove breakout box. Repeat QUICK TEST PROCEDURES . If any reading is greater than 5 ohms, go to next step.
4) Check For Short to Ground With key off and breakout box installed, leave ECA disconnected. Disconnect clutch interlock switch. Set DVOM on 200-k/ohm scale. Measure resistance between test pins No. 30 and 46. If resistance is greater than 10 k/ohms, for vehicles with A/C go to step 10. For all other vehicles, replace ECA, remove breakout box and repeat QUICK TEST PROCEDURES . If resistance is not greater than 10 k/ohms, repair short circuit, remove breakout box and reconnect ECA. Repeat QUICK TEST.
5) Check Neutral Gear/Clutch Switch Turn key off and wait 10 seconds. Leave breakout box installed and ECA disconnected. Set DVOM on 200-ohm scale. Locate Neutral Gear Switch (NGS) on transmission and Clutch Switch (CS) at clutch pedal linkage. Disconnect harness at both switches and inspect connector for pins that are pushed back. Measure resistance across NGS terminals with transmission in Neutral, and across CS terminals with clutch pedal depressed. If both resistances are less than 5 ohms, go to next step. If all resistances are more than 5 ohms, replace open switches as necessary, remove test equipment, reconnect components and repeat QUICK TEST PROCEDURES .
6) Check Neutral Gear/Clutch Harness With key off, set DVOM on 200-ohm scale. Install breakout box, leaving ECA disconnected. Disconnect vehicle harness at NGS and CS. Measure resistance between test pin No. 30 and NGS harness connector. Measure resistance between test pin No. 30 and CS harness connector. Measure resistance between test pin No. 46 and NGS harness connector. Measure resistance between test pin No. 46 and CS harness connector. If each resistance is less than 5 ohms, for vehicles with A/C, go to step 10. For all others, replace ECA. If resistance is not less than 5 ohms, repair open circuit, remove breakout box, reconnect all components and repeat QUICK TEST PROCEDURES .
7) Check Clutch Engage Switch Turn key off. Disconnect ECA 60-pin connector. Inspect for and repair any damaged wiring. Install breakout box and leave ECA disconnected. Set DVOM on 200-ohm scale. Depress clutch pedal. Measure resistance between test pins No. 30 and 46. If both readings are less than 5 ohms, on vehicles equipped with air conditioning, go to step 10. If not equipped with A/C, replace ECA. If any reading is 5 ohms or more, repair open circuit. Remove breakout box and reconnect all components. Repeat QUICK TEST PROCEDURES .

Fig 2: Checking Clutch Switch Circuit
8) Check Neutral Drive Input Turn key off and wait 10 seconds. Ensure heater control is in OFF position. Ensure transmission is in Neutral or Park position. Disconnect ECA 60-pin connector. Inspect for and repair any damaged wiring. Install breakout box and leave ECA disconnected. Set DVOM to 20-volt scale. Connect ECA to breakout box. With KOEO, measure voltage between test pin No. 30 at the breakout box and chassis ground. If voltage is less than one volt, on vehicles equipped with A/C, go to step 10. If not equipped with A/C, replace ECA. If reading is more than one volt, go to next step.

Fig 3: Checking NDS Switch Circuit
9) Check Neutral Drive Switch Turn key off and wait 10 seconds. Install breakout box, leave ECA disconnected. Set DVOM on 200-ohm scale. Disconnect vehicle harness from NDS at transmission and measure resistance across switch. If resistance is less than 5 ohms, remove breakout box. Reconnect all components and service open in NDS circuit. If resistance is more than 5 ohms, replace NDS and rerun QUICK TEST PROCEDURES .
10) Check A/C Input On vehicles equipped with E4OD transmissions, ensure transmission is in Park. Ensure A/C is turned off. If A/C was on, rerun QUICK TEST PROCEDURES . If Code 67 or 79 is displayed, continue with this test.
Install breakout box and leave ECA disconnected. With KOEO, set DVOM on 20-volt scale. Measure voltage at test pin No. 10 at the breakout box and chassis ground. If reading is greater than one volt, remove breakout box and repair short to power in A/C clutch power circuit. If voltage is less than one volt, replace ECA, except on vehicles equipped with E4OD transmissions. Vehicles equipped with E4OD transmissions, go to TEST D25, step 1. Reconnect all components and rerun QUICK TEST.

Fig 4: Checking A/C Input
11) Check A/C Input Circuit A low idle with A/C on could result in the ECA not receiving or recognizing A/C input on pin No. 10. Turn key off and wait 10 seconds. Disconnect ECA, inspect pins, and install breakout box. Leave ECA disconnected. Set DVOM on 20-volt scale. With KOEO, and A/C on, measure voltage between test pins No. 10 and 40. If voltage is greater than 10.5 volts, replace ECA. Remove breakout box. Reconnect all components and rerun QUICK TEST PROCEDURES . If voltage is less than 10.5 volts, repair open in A/C circuit. Remove breakout box and reconnect all components. Repeat QUICK TEST.

Fig 5: Checking A/C Clutch Circuit

NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 11 to step 13. No test procedures have been omitted.
13) Check Neutral Drive Input With key off, ensure transmission is in Park or Neutral. Disconnect ECA, inspect pins, and install breakout box. Reconnect ECA. Disconnect 16-pin connector from 4EAT transmission module. Set DVOM on 20-volt scale. With KOEO, measure voltage between test pin No. 30 at the breakout box and chassis ground. If voltage is less than one volt, replace ECA. Remove breakout box and reconnect all components. Repeat QUICK TEST PROCEDURES . If voltage is not less than one volt, go to next step.

Fig 6: Checking NDS Input Circuit
14) Check NDS Circuit Continuity Between ECA & 4EAT Module With key off, disconnect 4EAT module 16-pin connector. Install breakout box leaving ECA disconnected. Set DVOM on 200-ohm scale. Measure resistance between test pin No. 30 and NDS pin at 4EAT module vehicle harness connector. If resistance is less than 5.0 ohms, EEC-IV system is not at fault, repair or replace transmission components as necessary. Remove breakout box and reconnect all components. If resistance is greater than 5 ohms, repair open circuit, remove breakout box and reconnect all components. Repeat QUICK TEST PROCEDURES .

Fig 7: Checking 4EAT Module Circuits
15) Check For Nonfunctioning A/C With High Idle A high idle when the A/C dash switch is on, but A/C is not functioning, may be the result of no signal being received at the A/C clutch. Turn key off and wait 10 seconds. Disconnect ECA 60-pin connector. Inspect for corroded or damaged connector pins and repair as necessary. Install breakout box, leaving ECA disconnected. Disconnect A/C clutch connector. Set DVOM on 20-volt scale. With KOEO and A/C on, measure voltage between input pin on fan connector and test pin No. 40 at the breakout box. If voltage is greater than 10.5 volts, go to next step. If not, repair open in A/C circuit. Remove breakout box, reconnect all components and repeat QUICK TEST PROCEDURES .

Fig 8: Checking A/C Clutch Circuits
16) Check Continuity of A/C Clutch With KOEO, install breakout box, leaving ECA disconnected. Disconnect A/C clutch harness connector. Set DVOM on the 200-ohm scale. Measure resistance across both pins of the A/C clutch. If resistance is within normal specification of 2.14-3.34 ohms, fault was probably due to faulty A/C clutch connection. Check for damaged or loose pins. Remove breakout box, reconnect all components and repeat QUICK TEST PROCEDURES . If resistance was not within specification, repair or replace A/C clutch as necessary.
17) Check Continuity of A/C Cycle Pressure Switch Circuit Turn the key off and wait 10 seconds. Disconnect the ECA, inspect pins, and install breakout box. Leave ECA disconnected. Disconnect A/C cycle pressure switch. Turn A/C switch to ON position. Set DVOM on 200-ohm scale.
Measure resistance between test pin No. 10 at the breakout box and negative side of the A/C cycle pressure switch connector.

If resistance is less than 5 ohms, EEC-IV system is not at fault. Repair or replace cycle pressure switch. If resistances are greater than 5 ohms, repair open circuit and remove breakout box. Reconnect all components and repeat QUICK TEST PROCEDURES .
18) Check A/C Demand & A/C Cycle Pressure Switch For Short to Power Turn key off. Disconnect ECA, inspect pins, and install breakout box. Leave ECA disconnected. Ensure A/C switch is off. Set DVOM on 20-volt scale. With KOEO, measure voltage between test pin No. 43 and chassis ground. If voltage is greater than 1.0 volt, EEC-IV is okay. Check A/C switches, if okay, repair short circuit or re-evaluate symptom. Remove breakout box, reconnect all components and repeat QUICK TEST PROCEDURES . If voltage is less than 1.0 volt, diagnose faulty A/C clutch. If clutch is okay, replace ECA.
NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 18 to step 20. No test procedures have been omitted.
20) Check NDS Circuit For Short to Ground or Closed NDS Turn key off and wait 10 seconds. Disconnect ECA 60-pin connector, inspect pins, and install breakout box, leaving ECA disconnected. Place transmission in Drive. Set DVOM on 200-k/ohm scale. Measure resistance between test pin No. 30 and test pin No. 40 and 60 at breakout box. If resistance is greater than 10 k/ohms, service high idle condition. If resistance is less than 10 k/ohms, service circuit short or closed NDS. Remove breakout box, reconnect all components and repeat QUICK TEST PROCEDURES .