Iac
Thread Starter
Teching In
Joined: Aug 2010
Posts: 16
Likes: 0
Iac New install
5.3, 700R4, Jeep
motor is from a 2004, throttle body is from a 2001, performance tune, and harness from Jim's performance, got a few kinks worked out
It has idled super high 1800-2100 rpms since the first start up, throws a IAC code that reads, senses high idle
I have swapped IAC from jeep to running tahoe, both IAC's perform great on the tahoe
I have continuity through all 4 IAC wires from the computer to the harness plug, so wiring is all good
I can manually manipulate the IAC, pull it out, push it in, and I guess the computer will not change it
computer came out of a running, driving vehicle, what else am i looking for?
5.3, 700R4, Jeep
motor is from a 2004, throttle body is from a 2001, performance tune, and harness from Jim's performance, got a few kinks worked out
It has idled super high 1800-2100 rpms since the first start up, throws a IAC code that reads, senses high idle
I have swapped IAC from jeep to running tahoe, both IAC's perform great on the tahoe
I have continuity through all 4 IAC wires from the computer to the harness plug, so wiring is all good
I can manually manipulate the IAC, pull it out, push it in, and I guess the computer will not change it
computer came out of a running, driving vehicle, what else am i looking for?
Are you the PCM is right for the job? Some PCMs have
the IAC driver circuitry missing.
Measure each IAC phase to GND with a DMM with the
engine running, poke through the insulation with a
needle & clip-lead. If you see less than 100mV on all
of them, the PCM isn't trying.
Ran into this on an '04 Silverado AWD doing a big cable
TB swap, had to go to an '03 Savana PCM.
the IAC driver circuitry missing.
Measure each IAC phase to GND with a DMM with the
engine running, poke through the insulation with a
needle & clip-lead. If you see less than 100mV on all
of them, the PCM isn't trying.
Ran into this on an '04 Silverado AWD doing a big cable
TB swap, had to go to an '03 Savana PCM.
Thread Starter
Teching In
Joined: Aug 2010
Posts: 16
Likes: 0
Are you the PCM is right for the job? Some PCMs have
the IAC driver circuitry missing.
Measure each IAC phase to GND with a DMM with the
engine running, poke through the insulation with a
needle & clip-lead. If you see less than 100mV on all
of them, the PCM isn't trying.
Ran into this on an '04 Silverado AWD doing a big cable
TB swap, had to go to an '03 Savana PCM.
the IAC driver circuitry missing.
Measure each IAC phase to GND with a DMM with the
engine running, poke through the insulation with a
needle & clip-lead. If you see less than 100mV on all
of them, the PCM isn't trying.
Ran into this on an '04 Silverado AWD doing a big cable
TB swap, had to go to an '03 Savana PCM.
Can it be added to a pcm that doesnt have it, by a tune?
Teching In
Joined: Sep 2010
Posts: 43
Likes: 0
From: fresno
Are you the PCM is right for the job? Some PCMs have
the IAC driver circuitry missing.
Measure each IAC phase to GND with a DMM with the
engine running, poke through the insulation with a
needle & clip-lead. If you see less than 100mV on all
of them, the PCM isn't trying.
Ran into this on an '04 Silverado AWD doing a big cable
TB swap, had to go to an '03 Savana PCM.
the IAC driver circuitry missing.
Measure each IAC phase to GND with a DMM with the
engine running, poke through the insulation with a
needle & clip-lead. If you see less than 100mV on all
of them, the PCM isn't trying.
Ran into this on an '04 Silverado AWD doing a big cable
TB swap, had to go to an '03 Savana PCM.
Trending Topics
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo
Awesome K5 Blazer Restomod Comes With C7 Corvette Power
Verdad Gallardo
10 Camaros You Should Never Buy
10 LS Engine Myths That Refuse to Die
Verdad Gallardo PCM's with IAC drivers Green is good Red is not
SERV. NO.- HWD NO. -
12576106 - 12570558 - 2003 G-VAN, LM7, IAC DRIVERS INSTALLED. ALSO C-TRUCK LM7
12582605 - 12580786 - 2003 C-MPV, L59
12586242 - 12583660 - 2004 C/K-TRUCK, LM7
12586243 - 12583659 - 2004 GTO LS1, IAC DRIVERS INSTALLED
12589463 - 12589162 - 2005 C/K-TRUCK/MPV, LM7, LQ4
12589462 - 12589161 - 2005 G-VAN, LQ4, IAC DRIVERS INSTALLED
12589463 - 12589162 - 2006 C-PICKUP, LM7
12602802 - 12589162 - 2006 C-PICKUP, L59
12602801 - 12589161 - 2006 - 2007 Express, Drive by Wire, (has IAC drivers)
12576106 - 12570558 - 2003 G-VAN, LM7, IAC DRIVERS INSTALLED. ALSO C-TRUCK LM7
12582605 - 12580786 - 2003 C-MPV, L59
12586242 - 12583660 - 2004 C/K-TRUCK, LM7
12586243 - 12583659 - 2004 GTO LS1, IAC DRIVERS INSTALLED
12589463 - 12589162 - 2005 C/K-TRUCK/MPV, LM7, LQ4
12589462 - 12589161 - 2005 G-VAN, LQ4, IAC DRIVERS INSTALLED
12589463 - 12589162 - 2006 C-PICKUP, LM7
12602802 - 12589162 - 2006 C-PICKUP, L59
12602801 - 12589161 - 2006 - 2007 Express, Drive by Wire, (has IAC drivers)
Last edited by CalEditor; Oct 29, 2010 at 02:36 PM.
Thread Starter
Teching In
Joined: Aug 2010
Posts: 16
Likes: 0
not sure if the injectors are leaking, motor didnt have but 38,000 miles on it from the wrecked vehicle
how do you check pulse width?
I had a lean and rich code at first, but o2 sensors were backwards
Teching In
Joined: Sep 2010
Posts: 43
Likes: 0
From: fresno
I don't really see a injectors with 38k mi. on them leaking. You could use a DSO, such as a picoscope, but doubt you would want to pay full price for one.
Thread Starter
Teching In
Joined: Aug 2010
Posts: 16
Likes: 0
New computer didnt change a thing, still high idle
I put the old computer back in, pulled the IAC out, manually pulled it completely out where the IAC seperated the plunger from the spring, put it back together enough to where it should be at idle, reinstalled the IAC, and it sat there and idled perfect
The computer is not controlling the IAC
I put the old computer back in, pulled the IAC out, manually pulled it completely out where the IAC seperated the plunger from the spring, put it back together enough to where it should be at idle, reinstalled the IAC, and it sat there and idled perfect
The computer is not controlling the IAC
1999 to 2002 all PCM's support IAC
2003+
SERV. NO. - HWD NO.
12576106 - 12570558 - 2003 G-VAN, LM7, IAC DRIVERS. C1500 LM7
12586243 - 12583659 - 2004 GTO LS1, IAC DRIVERS
12589462 - 12589161 - 2005 G-VAN, LQ4, IAC DRIVERS
12602801 - 12589161 - 2006 - 2007 Express, Drive by Wire, (has IAC drivers)
2004
Silverado PCM, DOES NOT WORK with cable throttle:
Serv. No. 12586242
Hwd. No. 12593660
2005 & 2006
Silverado PCM, DOES NOT WORK with cable throttle:
Serv. No. 12589463
Hwd. No. 12589162
2003+
SERV. NO. - HWD NO.
12576106 - 12570558 - 2003 G-VAN, LM7, IAC DRIVERS. C1500 LM7
12586243 - 12583659 - 2004 GTO LS1, IAC DRIVERS
12589462 - 12589161 - 2005 G-VAN, LQ4, IAC DRIVERS
12602801 - 12589161 - 2006 - 2007 Express, Drive by Wire, (has IAC drivers)
2004
Silverado PCM, DOES NOT WORK with cable throttle:
Serv. No. 12586242
Hwd. No. 12593660
2005 & 2006
Silverado PCM, DOES NOT WORK with cable throttle:
Serv. No. 12589463
Hwd. No. 12589162
Thread Starter
Teching In
Joined: Aug 2010
Posts: 16
Likes: 0
1999 to 2002 all PCM's support IAC
2003+
SERV. NO. - HWD NO.
12576106 - 12570558 - 2003 G-VAN, LM7, IAC DRIVERS. C1500 LM7
12586243 - 12583659 - 2004 GTO LS1, IAC DRIVERS
12589462 - 12589161 - 2005 G-VAN, LQ4, IAC DRIVERS
12602801 - 12589161 - 2006 - 2007 Express, Drive by Wire, (has IAC drivers)
2004
Silverado PCM, DOES NOT WORK with cable throttle:
Serv. No. 12586242
Hwd. No. 12593660
2005 & 2006
Silverado PCM, DOES NOT WORK with cable throttle:
Serv. No. 12589463
Hwd. No. 12589162
2003+
SERV. NO. - HWD NO.
12576106 - 12570558 - 2003 G-VAN, LM7, IAC DRIVERS. C1500 LM7
12586243 - 12583659 - 2004 GTO LS1, IAC DRIVERS
12589462 - 12589161 - 2005 G-VAN, LQ4, IAC DRIVERS
12602801 - 12589161 - 2006 - 2007 Express, Drive by Wire, (has IAC drivers)
2004
Silverado PCM, DOES NOT WORK with cable throttle:
Serv. No. 12586242
Hwd. No. 12593660
2005 & 2006
Silverado PCM, DOES NOT WORK with cable throttle:
Serv. No. 12589463
Hwd. No. 12589162
my computer numbers
serv. No. 12586242
hwd. no. 12583660
Test computer I got yesterday, doesnt have IAC drivers
serv. no. 12589463
hdw. no. 12589162
Last edited by guffey24; Oct 29, 2010 at 09:47 AM.