Can someone confirm faulty ICM module???

+ Reply to Thread
Results 1 to 8 of 8
  1. #1
    1st Gear
    Join Date
    May 2000
    Location
    Irvine, CA USA
    Posts
    199

    Can someone confirm faulty ICM module???

    Here's the measurements... (I'm guessing Source-Drain off resistence???)
    5-pin side --> 4-pin side (right to left facing connector)
    Pin 3 --> Pin 1 = 138 kOhm
    Pin 3 --> Pin 2 = open
    Pin 3 --> Pin 3 = 138 kOhm
    Pin 3 --> Pin 4 = 138 kOhm

    Symptom is rough idle and P302 code (Misfire at Cylinder 2).

    I'm about to order an ICM module ... but just wanted to feel at ease instead of just throwing parts at the problem. This has happened before (at 80k miles) with worse symptoms (completely dead engine on the freeway). I'm now at 190k miles.

    BTW... Engine is '98 AEB

  2. Remove Advertisements
    VW Passat Forum
    Advertisements
     

  3. #2
    Neutral
    Join Date
    Feb 2006
    Posts
    128
    Hey I'm suspecting my ICM too. My readings on a Bosch unit on my 1998 1.8t were:

    (from pin 3 to the other 4 pins like OP)
    Pin 3 --> Pin 1 = >2 MOhm (as high as my multimeter goes) -- I assume it's open
    Pin 3 --> Pin 2 = 287 kOhm
    Pin 3 --> Pin 3 = 287 kOhm
    Pin 3 --> Pin 4 = 287 kOhm

    I was getting misfires on cylinder 1 and "random misfire." There were no other codes to hint at MAF or other things.

  4. #3
    2nd Gear
    Join Date
    Aug 2004
    Location
    Middletown, CT
    Posts
    503
    Guys, if you're getting random misfires on on coilpack, clear codes, swap coilpack positions around, and see if the misfire moves with the coilpack. (Or resistance moves with the coilpack!)

    If it moves with the same coilpack, faulty coilpack. If it moves randomly, faulty ICM. ICM's seem to go anyway at 70-80k miles, and not too $ to replace. I saw a new for under $60 somewhere, but usually around $100.

    Always use new heat sink paste! Early failure otherwise.

  5. #4
    3rd Gear
    Join Date
    Nov 2000
    Location
    Ocala FL
    Posts
    1,765
    Chip, yours looks to be a totally textbook ICM failure, right down to #2 cylinder being the most common of the four to fail. The typical failure mode is for one of the bond wires from the pin to the actual semiconductor inside the module to break loose. They just don't seem to have been bonded correctly in a lot of cases. I'd be about 95% confident that this is what happened to yours

    Rocko, your failure on the #1 pin is a bit less textbook, but the measurements indicate the same problem, an open circuit inside the ICM. I'd still be 95% confident that's the problem.

    Click here for gory internal details.

  6. #5
    Banned
    Join Date
    Sep 2006
    Location
    Ashburn, VA
    Age
    32
    Posts
    8,987
    For what it's worth, some people say the Huco aftermarket ICMs last longer than the Bosch OEM units.

  7. #6
    Neutral
    Join Date
    Feb 2006
    Posts
    128
    Quote Originally Posted by DaddyMatt View Post
    Rocko, your failure on the #1 pin is a bit less textbook, but the measurements indicate the same problem, an open circuit inside the ICM. I'd still be 95% confident that's the problem.

    Click here for gory internal details.
    I took a look inside. The corresponding connector was loose. I see you cannot solder in there, which is too bad. I have doubts about shimming in a screw because I don't want to short to the heat sink. If the heat sink isn't grounded, then I suppose it's ok, but I certainly wouldn't shim more than one at the risk of having the ground short them together.

    I have a new one coming overnight. All the local places want more than $240 for it, and I can drive around in my short school bus for a day.

  8. #7
    1st Gear
    Join Date
    May 2001
    Location
    Columbia, MD
    Posts
    318
    Quote Originally Posted by Rocko Bonaparte View Post
    Hey I'm suspecting my ICM too. My readings on a Bosch unit on my 1998 1.8t were:

    (from pin 3 to the other 4 pins like OP)
    Pin 3 --> Pin 1 = >2 MOhm (as high as my multimeter goes) -- I assume it's open
    Pin 3 --> Pin 2 = 287 kOhm
    Pin 3 --> Pin 3 = 287 kOhm
    Pin 3 --> Pin 4 = 287 kOhm

    I was getting misfires on cylinder 1 and "random misfire." There were no other codes to hint at MAF or other things.
    Rocko -

    I had a failure on number 1 as well. It was open, as well as 3 and 4 were failing as indicated by the 1.664 MOhm reading. I installed my Huco replacement today and all is well.

    Good luck
    -K2

  9. #8
    1st Gear
    Join Date
    May 2000
    Location
    Irvine, CA USA
    Posts
    199
    I received my replacement ICM today. It has a Hamburg label on it... Maybe a 3rd party manufacturer for Bosch. It's the same plastic casing as the broken Bosch unit with the original part # stamped on the heatsink side .... not like the rectangular Huco unit.

    Engine runs fine now. I replaced the Bosch Super plugs with some cheap $1.50 copper core Champion spark plugs during troubleshooting of the initial problem (misfire @ cylinder 2). It's a colder plug I believe. RC12YC vs. RC9YC. I stayed away from platinum since I've heard that our AEB's don't react to well with them. I'll leave the plugs in for a bit since the engine runs great so far with them.

  10. Remove Advertisements
    VW Passat Forum
    Advertisements
     

Quick Reply Quick Reply

Register Now

Please enter the name by which you would like to log-in and be known on this site.
If you do not want to register, fill this field only and the name will be used as user name for your post.

Please enter a password for your user account. Note that passwords are case-sensitive.

Please enter a valid email address for yourself.

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.


Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
Powered by vBadvanced CMPS v4.1.2