Test Aa - Idle Speed CTRL (ISC) Dc Motor/Idle Tracking SW

(ITS) ASSEMBLY

1. Key ON/Engine OFF Code 68 Displayed. Turn key OFF and wait 10 seconds. Move throttle away from Idle Speed Control (ISC) motor shaft to simulate NO throttle contact. Repeat Key ON/Engine OFF Self-Test and note codes. If code 68 is displayed, go to step 3). If code 68 is not displayed, go to next step. Ignore all other codes at this time.
2. Turn key OFF and wait 10 seconds. Install breakout box, leaving ECA disconnected. Connect jumper wire between test pins 41 and 1 and between test pin 21 and ground. If ISC DC motor retracts, check ISC mechanical adjustments. If motor does not retract, go to step 5).
3. Turn key OFF and wait 10 seconds. Disconnect harness at ISC motor. Connect jumper between connector pins 3 and 4 to simulate closed contact condition. Perform Key ON/Engine OFF Self-Test. If code 68 is not displayed, replace ISC DC motor and repeat QUICK TEST  . If code 68 is displayed, go to next step.
4. Turn key OFF and wait 10 seconds. Disconnect 60-pin ECA connector. Inspect for and repair any damaged wiring. Connect breakout box and leave ECA disconnected. With harness disconnected at ISC, place DVOM on 200,000 ohm scale. Measure resistance between test pin 28 and idle tracking switch (ITS) circuit at ISC connector. Also measure resistance between test pin 46 and signal return at ISC connector. If either reading is 5 ohms or more, repair circuit. Repeat QUICK TEST  . If both readings are less than 5 ohms, replace ECA. Repeat QUICK TEST  .
5. Turn key OFF and wait 10 seconds. Disconnect ECA 60-pin connector. Inspect for and repair any damaged wiring. Connect breakout box, leaving ECA disconnected. Disconnect ISC motor harness and set DVOM to 200 ohm scale. Measure resistance between test pin 41 and ISC ground circuit and between test pin 21 and ISC power circuit at ISC connector. If either reading is 5 ohms or more, repair wiring and repeat QUICK TEST  . If both readings are less than 5 ohms, go to next step.
6. Turn key ON, leaving engine OFF. Leave breakout box connected and ECA disconnected. Leave harness disconnected from ISC motor and set DVOM to 20 volt scale. Measure voltage between test pin 41 and test pins 40 and 60. Also measure voltage between test pin 21 and test pins 40 and 60. If any reading is 1 volt or more, repair short to power. Repeat QUICK TEST  . If code 12 is still displayed, replace ECA and repeat QUICK TEST  . If all readings are less than 1 volt, go to next step.
7. Turn key OFF and wait 10 seconds. Leave breakout box installed with ECA and ISC motor disconnected. Set DVOM to 200,000 ohm scale. Measure resistance between test pin 41 and test pins 40, 46 and 60. Also measure resistance between test pin 21 and test pins 40, 46, and 60. If any reading is 10,000 ohms or less, repair bad circuit. Repeat QUICK TEST  . If code 12 is still displayed, replace ECA and repeat QUICK TEST  . If all readings are more than 10,000 ohms, go to next step.
8. Turn key OFF and wait 10 seconds. Set DVOM to 20 volt scale, leaving breakout box installed with ECA and ISC motor disconnected. Connect positive test lead to test pin 1 and negative test lead to ground. If reading is less than 10.5 volts, repair open in KAPWR circuit. Repeat QUICK TEST  . If code 12 is still displayed, go to next step. If reading is 10.5 volts or more, go to next step.
9. Turn key OFF and wait 10 seconds. Leave breakout box installed and ECA disconnected. Connect ISC motor. Jump wire test pin 21 to test pin 1 and test pin 41 to ground. If DC motor shaft does not extend 2 in. (5 cm.) or more, replace DC motor. Repeat QUICK TEST  . If motor shaft does extend far enough, go to next step.
10. Turn key OFF and wait 10 seconds. Leave breakout box installed and ECA disconnected. Jump wire test pin 41 to test pin 1 and test pin 21 to ground. If shaft does not retract, replace motor. Repeat QUICK TEST  . If shaft does retract, go to next step.
11. Turn key OFF and wait 10 seconds. Leave breakout box installed and ECA disconnected. Jump wire test pin 21 to test pin 1 and test pin 41 to ground. If shaft does not extend, replace motor and repeat the QUICK TEST  . If shaft does extend, replace ECA and repeat QUICK TEST  .
12. Code 58 Displayed. Turn key OFF and wait 10 seconds. Press on ISC motor shaft to simulate throttle contact. Run Key ON/Engine OFF Self-Test while maintaining pressure on shaft. If code 68 is displayed, go to step 5). If code 68 is not displayed, go to next step. Ignore all other codes at this time.
13. Turn key OFF and wait 10 seconds. Leave breakout box connected and ECA disconnected. Jump wire test pin 41 to test pin 1 and test pin 21 to ground. If motor shaft retracts, check ISC motor adjustments. If shaft does not retract, go to next step.
14. Turn key OFF and wait 10 seconds. Disconnect harness from ISC. Run Key ON/Engine OFF Self-Test. If code 68 is displayed, replace DC motor and repeat QUICK TEST  . If code 68 is not displayed, go to next step. Ignore all other codes during this step.
15. Turn key OFF and wait 10 seconds. Disconnect ECA 60-pin connector. Inspect for and repair any damaged wiring. Connect breakout box, leaving ECA disconnected. Disconnect ISC and set DVOM to 200,000 ohm scale. Measure resistance between test pin 28 and test pins 40, 46, and 60. If any reading is less than 10,000 ohms, repair short to ground. Repeat QUICK TEST  . If all readings are 10,000 ohms or more, replace ECA. Repeat QUICK TEST  .
16. Code 12 Displayed. If codes 58, 68, 31, or 41 are also displayed, go to Engine Running Self-Test results for correct test. If these codes are not displayed, go to next step.
17. Check throttle plates and linkages for binding. If vehicle has speed control, make sure that no binding occurs in speed control linkage. If mechanical repair is made, repeat QUICK TEST  . If no problem is found with linkages or throttle plates, go to next step.
18. Turn key OFF and wait 10 seconds. Leave breakout box installed and ECA disconnected. Jump wire test pin 21 to test pin 1 and test pin 41 to ground. If motor shaft does not extend, replace DC motor and repeat QUICK TEST  . If shaft does extend, replace ECA and repeat QUICK TEST  .
19. Code 13 Displayed. This code is displayed if engine is not returning to proper idle RPM. Prepare vehicle for normal operation. Turn A/C OFF and deactivate Self-Test mode. Start and run engine. Run at idle for 30 seconds, then partial throttle for 5 seconds, then return to idle for 30 seconds. Repeat this sequence for 3 minutes. If idle speed is erratic, check for: vacuum leaks or any of codes 22, 31, 41, or 58 being displayed. Repair codes or leaks before proceeding. If idle speed is not erratic, go to next step.
20. Check throttle plate linkages for sticking or binding. Check choke for sticking or binding. Make sure throttle does not hang on high cam step. If any fault is found, repair and repeat QUICK TEST  . If no fault is found, go to next step.
21. Run Key ON/Engine OFF Self-Test and record On Demand codes. If code 68 is displayed, go to step 1) of this test. If code 68 is not displayed, check anti-diesel speed adjustments.