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Old 04-02-2008, 01:56 PM   #1
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Default ICM harness question...

Ok, I think I made a major breakthrough with my rough idle, stalling, and Code 41 & 43.

I thought to my self "Self, is it a possibility that I have a short in the ICM/Crank/Cam Sensor harness?"

It all comes clear now, these are the ONLY codes I get, and that they happen to be associated with that harness. Sometimes the SES goes off completely, but will come back on shortly after that, mostly Code 41, but 43 also pops up alot, random stalling, occasinal misfire, backfires on revs, it all seems clear now. My question is, do I have to take my HB off to disconnect the crank sensor? I haven't looked (too lazy). Reason I want to disconnect it is so I can get the whole harness off, and check for continuity in the wires. TIA!
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Old 04-02-2008, 02:26 PM   #2
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No, you can disconnect the sensor w/o removing the balancer. If you are getting both the crank and cam sensor codes, I would check the sensor grounds, AND the connection at the ICM. Sometimes those get oil soaked for some reason or the wires get bared. Same story with the crank/cam wires.
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Old 04-02-2008, 02:34 PM   #3
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Yes, you CAN unplug the crank sensor with the HB on.
Biggest issue is the 8way plug. It won't feed through the small opening without messing with the tensioner bracket.

If you haven't done so, however, check the connections at ground point G100, which is closest to the center of the engine of the 2 studs that the ICM plate mounts on. This is PCM ground source.

I was in the middle of replacing the harness with a salvage unit, when I discovered this ground had come slightly loose. I went ahead and swapped out the harness, but can't swear which was the cause. But that is when I got rid of a code 18.
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Old 04-02-2008, 04:33 PM   #4
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Well, after a while of cursing and bi**hing, I got the harness out. I had to take the tensioner bracket off, but I got it. The one thing I don't like is how the wires feel. They feel kinda soft, like how they feel after being soaked in oil for a long time.

Anyone got a spare harness laying around? Of course, let me get the verdict first by checking the continuity of the wires first.
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Old 04-02-2008, 04:37 PM   #5
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I have some series2 ICM harnesses around here. If they will work on a series1 you know where to go.

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Old 04-02-2008, 06:07 PM   #6
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Quote:
Originally Posted by 93RedSled-SSE
Yes, you CAN unplug the crank sensor with the HB on.
I said that...I think.

And yes, S2 ICM harnesses will in fact work. There is an added ground wire that isn't present on the S1 harness that goes to pin K on the ICM...that is the only difference.
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Old 04-02-2008, 07:04 PM   #7
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Yeah, it took a little coaxing, but I managed to get it unplugged. I had to stick a small screwdriver behind the HB to unplug the clip.

Andrew, I'll take one of those harnesses, probably the middle one, it looks the best. PM me with the total cost.
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Old 04-02-2008, 09:57 PM   #8
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Well, it looks like since I am torn down so much, I am going to go ahead and pull the timing cover, and do the chain and gears, along with a new oil pan gasket, and some other stuff. I figure heck, it'* torn down that far, fix it before it breaks.

Andrew.... PayPal coming your way for the harness.
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Old 04-05-2008, 03:56 PM   #9
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Got the "new" harness today, looks great and is in a LOT better shape than the old one. Tomorrow starts the rest of the teardown to do the timing chain, crank sensor, etc etc. Better safe than sorry.

Where should I support the engine when I pull the TA mount? I am not exactly sure.
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Old 04-05-2008, 04:01 PM   #10
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get a jack and a block of wood under the oil pan.
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