Circuit Test D20
NOTE:
Perform this test only when service Code 81, is displayed during KOEO SELF-TEST or directed here by DIAGNOSIS BY SYMPTOM test.
- Code 81: Check Solenoid Resistance. Code 81 indicates IAC solenoid output voltage did not change when IAC was activated during KOEO SELF-TEST. Possible causes for this fault are: IAC circuit open, shorted or disconnected or ECA output driver open or grounded. Turn key off and wait 10 seconds. Set DVOM on 200-ohm scale and disconnect IAC solenoid connector from harness. Measure resistance of solenoid. If resistance is 50-100 ohms, go to next step. If resistance is not 50-100 ohms, replace solenoid and rerun QUICK TEST.
- Check Voltage of VPWR Circuit. With KOEO, disconnect IAC solenoid. Set DVOM on 20-volt scale. Measure voltage between VPWR circuit of IAC solenoid harness connector and battery negative post. If voltage is greater than 10.5 volts, go to next step. If voltage is less than 10.5 volts, reconnect IAC solenoid, repair open circuit in harness and rerun QUICK TEST.
- Check Continuity of IAC Solenoid Circuit. Turn key off and wait 10 seconds. Disconnect 60-pin ECA connector. Inspect pins for corrosion or damage and service as necessary. Install breakout box, leave ECA disconnected. Set DVOM on 200-ohm scale. Measure resistance between test pin No. 32 at the breakout box and IAC harness connector. If resistance is less than 5 ohms, go to next step. If resistance is greater than 5 ohms, repair open circuit and rerun QUICK TEST.
- Check For Short to Ground. Turn key off and wait 10 seconds. With breakout box installed and ECA disconnected, set DVOM on 200K-ohm scale. Disconnect IAC solenoid. Measure resistance between test pin No. 32 and test pins No. 40, 46 and 60 at the breakout box. If resistance is greater than 100K ohms, go to next step. If resistance is less than 100K ohms, repair short circuit, reconnect components and retest.
- Check For Short to Power. Turn key off and wait 10 seconds. With breakout box installed and ECA disconnected, set DVOM on 200K-ohm scale. Disconnect IAC solenoid. Measure resistance between test pin No. 32 and test pins No. 37 and 57 at the breakout box. If resistance is greater than 100K ohms, replace ECA, reconnect components and retest. If resistance is less than 100K ohms, repair short circuit, reconnect components and retest. If fault is still present, replace ECA.
- Checking Front and Rear Intake Air Valves. With key off, disconnect vacuum lines from both intake air valves. Check each air valve with a vacuum pump. Apply 10 in. Hg vacuum. If both valves hold vacuum, go to next step. If not, replace valve(s) as necessary and rerun QUICK TEST.
- Checking Air Valve Systems. With key off, apply 10 in. Hg to each air valve. If both valves and mechanical linkage move in response to the applied vacuum, go to next step. If valves and linkage are faulty, service as necessary and rerun QUICK TEST.
- Check Vacuum to Intake Air Valves. With key off, check the vacuum lines from air valves to IAC solenoid. Inspect for damage or blockage. If vacuum lines are okay, go to next step. If vacuum lines are faulty, service as necessary and retest.
- Check Vacuum Source to IAC Solenoid. Disconnect IAC solenoid vacuum supply hose from intake manifold. Start engine and check vacuum at the disconnected manifold hose. If vacuum is present at hose, replace IAC solenoid and rerun QUICK TEST. If vacuum is not present, check supply hose to IAC solenoid. Service as necessary and rerun QUICK TEST.