How Can I Test Ignition Control Module (ICM)??? - JeepForum.com
Search  
Sign Up   Today's Posts
User: Pass: Remember?
Advertise Here
Jeep Home Jeep Forum Jeep Classifieds Jeep Registry JeepSpace Jeep Reviews Jeep Gallery Jeep Clubs Jeep Groups Jeep Videos Jeep Events Jeep Articles
Go Back JeepForum.com > Models > Jeep Wrangler Forums > YJ Wrangler Technical Forum > How Can I Test Ignition Control Module (ICM)???

Introducing MONSTALINER™ UV Permanent DIY Roll On Bed LineFS: Wrangler RGB Multicolor Fog Light LEDs: Awesome EffectSavvy Aluminum Gas Tank Skid

Reply
Unread 05-08-2009, 12:36 PM   #1
inniett
Registered User
1989 YJ Wrangler 
 
Join Date: Mar 2009
Location: Tempe
Posts: 53
How Can I Test Ignition Control Module (ICM)???

I suspect it may be going out? How can I test if it is? Thank you.

inniett is offline   Reply With Quote
Unread 05-08-2009, 12:47 PM   #2
JEEPorado
Registered User
1990 YJ Wrangler 
 
Join Date: Apr 2009
Location: Vail, CO
Posts: 33
Redneck way: Start you jeep, hit it firmly with a hammer (don't break it), if the jeep stumbles or dies then it's time to replace the ignition module

Non redneck way: take it to autozone- they will test it for free.

If you suspect its going out, it may be worth buying a backup to keep for emegencies. Mine randomly went out two weeks ago- luckily the jeep was idling in my driveway but if it happened a week earlier I would have been 5 miles off road in a giant mud puddle
JEEPorado is offline   Reply With Quote
Unread 05-08-2009, 01:03 PM   #3
inniett
Registered User
1989 YJ Wrangler 
 
Join Date: Mar 2009
Location: Tempe
Posts: 53
How will they test it at autozone? I have a continuity tester and a 12-volt probe...? I called to see if they can test it and they said no. (they prob didn't know what I was talking about) Checker Auto wants $94 for a new one go figure. Hopefully I can get a quick reply before I go hitting stuff with a hammer.
inniett is offline   Reply With Quote
Unread 05-08-2009, 01:24 PM   #4
littleredjeep
Registered User
1988 YJ Wrangler 
 
Join Date: Jun 2008
Location: So. Missouri
Posts: 308
When you take it to Autozone they will plug the ICM into there little station. It is the same place they test there starters and alternators. I think they test them at O'Rielly too. They don't test them with a continuity tester or a test light.
littleredjeep is offline   Reply With Quote
Unread 05-08-2009, 01:38 PM   #5
JEEPorado
Registered User
1990 YJ Wrangler 
 
Join Date: Apr 2009
Location: Vail, CO
Posts: 33
Quote:
Originally Posted by inniett View Post
How will they test it at autozone? I have a continuity tester and a 12-volt probe...? I called to see if they can test it and they said no. (they prob didn't know what I was talking about) Checker Auto wants $94 for a new one go figure. Hopefully I can get a quick reply before I go hitting stuff with a hammer.
Autozones here test for free. When I bought a replacement ICM, they told me I could get my old one checked for free before buying the new one. Apparently the autozone you called is run by brainless monkeys.

Anyways, why do you think your ICM is going out?
JEEPorado is offline   Reply With Quote
Unread 05-08-2009, 02:20 PM   #6
inniett
Registered User
1989 YJ Wrangler 
 
Join Date: Mar 2009
Location: Tempe
Posts: 53
Because the car will randomly stall, have trouble starting, then show no symptoms at all. Also because I know it's not the carb or fuel. Last time it wouldn't start, (didn't have a helper) I hooked a timing light up to it while I tried to turn it over (no spark). I cleaned/rebuilt the carb, set float, etc, new fuel filter, dropped tank and cleaned as well. I get gas when it wont start.

Ironically it seems to be working fine now, until the stalling magically comes back!
inniett is offline   Reply With Quote
Unread 05-08-2009, 03:04 PM   #7
inniett
Registered User
1989 YJ Wrangler 
 
Join Date: Mar 2009
Location: Tempe
Posts: 53
Wow, so it tested fine and "PASSED" good news is they only want 39.99 for a new one... too bad it didn't "FAIL"... now what?
inniett is offline   Reply With Quote
Unread 05-08-2009, 05:30 PM   #8
JEEPorado
Registered User
1990 YJ Wrangler 
 
Join Date: Apr 2009
Location: Vail, CO
Posts: 33
I did the exact same thing with the timing light to test for spark when mine went out. It sounds like an ICM problem, buy the new ICM and if you can, buy a new coil (they're like $20). Replace both and you shouldn't have any other issues with starting... I am 90% sure
JEEPorado is offline   Reply With Quote
Unread 05-08-2009, 05:34 PM   #9
Burnerman
Registered User
1989 YJ Wrangler 
 
Join Date: Oct 2006
Location: Vernon, NJ
Posts: 4,756
Just buy a new ICM. Mine did the same thing. Sure, when they tested it it worked. Have them test it when your Jeep just shut off along the road.
__________________
89' YJ Larado 4.0L,AX15
05' Grand Cherokee Limited, 2"OME lift and a Hemi.
Burnerman is offline   Reply With Quote
Unread 05-08-2009, 10:41 PM   #10
inniett
Registered User
1989 YJ Wrangler 
 
Join Date: Mar 2009
Location: Tempe
Posts: 53
would a bad coil go in and out like that...? Yeah, I might as well buy a new ICM, and I'll do the nutter to that one!
inniett is offline   Reply With Quote
Unread 05-09-2009, 07:19 AM   #11
ctm
Registered User
1990 YJ Wrangler 
 
Join Date: May 2007
Location: Boston MA
Posts: 1,429
99% of the time random shut downs are due to a bad ICM...they will test fine and then leave you stranded.....for the trails buy two and keep a spare handy. It's a weak point of the system. Also look into TeamRush upgrade from the CJ forum and go with a CDI module. The Summit Racing house brand modules are just as good as the MSD and they are around $100
ctm is offline   Reply With Quote
Unread 05-09-2009, 07:39 AM   #12
Louie4
Powah Injanir
 
Louie4's Avatar
1993 YJ Wrangler 
 
Join Date: Aug 2008
Location: Raleigh, NC
Posts: 9,826
My beater went out on me the day before I went to pick up my new car. I tried to fix it because I thought it was the coil. Of course no Autozone in my area knows how to test anything (not a problem in my hometown) so I couldn't test the coil (no multimeter or book). By the way there was no spark. I bit the bullet and bought a $45 coil and put it in, nothing. I did some research and found the ignition control module in the distributor and took it out. I'm not going to pay $85 bucks for a new one so Pull A Part here I come. Anyway, this relates to your problem because before it went out I had sever occasions where my car would turn over and never fire, and once when I was going down the highway and it just cut out. I kept it in gear and it fired up again. What I'm getting at is it could be an intermittent problem.
__________________
Lou

I have a jeep...and it is modified...I win.

YJOTM July 2012
YJOTM February 2014

Louie4's YJ Build
Poison Spyder Fender Install
Warn M8000 Rebuild Adventure
University of Georgia
Louie4 is offline   Reply With Quote
Unread 05-09-2009, 04:33 PM   #13
timatoe
Registered User
1990 YJ Wrangler 
 
Join Date: Aug 2006
Location: Grass Valley California
Posts: 13,685
Quote:
Originally Posted by inniett View Post
would a bad coil go in and out like that...? Yeah, I might as well buy a new ICM, and I'll do the nutter to that one!
If you're gonna do that, I'd get a HEI distributor and be done with the ICM all together. I'd bet the coil is fine they typically work or don't.
__________________
Quote:
Originally Posted by George Orwell
We sleep safe in our beds because rough men stand ready in the night to visit violence on those who would do us harm.
timatoe is offline   Reply With Quote
Unread 05-10-2009, 02:15 AM   #14
inniett
Registered User
1989 YJ Wrangler 
 
Join Date: Mar 2009
Location: Tempe
Posts: 53
Thanks guys for all the posts, it's good to know other people had similiar symptoms and fixed it with a new ICM! Monday I'll get some time to finally fix this! I'll let you know how it goes!

PS I'm going to be so pissed if the thing stalls after the new ICM!
inniett is offline   Reply With Quote
Unread 05-10-2009, 07:35 AM   #15
ctm
Registered User
1990 YJ Wrangler 
 
Join Date: May 2007
Location: Boston MA
Posts: 1,429
also per Jeephammer's info on the CJ forums, run a new ground wire by splicing the black coming off the distributor and connect it to a known good ground like where the battery neg cable connects to the engine block. The stock setup grounds through the distributor clamp, and can cause intermittent problems.
ctm is offline   Reply With Quote
Reply
Thread Tools


Suggested Threads





Jeep, Wrangler, Cherokee, Grand Cherokee, and other models are copyrighted and trademarked to Jeep/Chrysler Corporation. JeepForum.com is not in any way associated with Jeep or the Chrysler Corp.