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P1509 Diagnostic Trouble Code Discussion for October 2005

Idle Speed High - IAC System Not Responding

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Trouble Ticket Help Requests for DTC P1509
Help Request Posted
1996 Chevrolet Astro 4.3L High Idle VIN: 1GNDM19W7T
P1509: Idle Speed High - IAC System Not Responding. This IAC will retract all the way but it will not extend?? Is this a PCM problem?? The idle is about 3000 rpm unless I manually extend the IAC and let it unplugged. If I try to control the IAC with the scanner it will only retract no matter which way I command...
October 19, 2005
1998 Chevrolet K1500 Cheyenne 5.7L Poor Idle Quality VIN: 2GCEK19R5W
P1509: Idle Speed High - IAC System Not Responding. Vehicle from another shop, engine has high idle(2000rpm) most of the time, key cycle or cold sit may idle ok for 5min after driving sticks in high again. Iac was aftermarket we replaced unit with a delco same problem. votage test to and from pcm appear to be o...
October 20, 2005