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-   1992-1999 (https://www.gmforum.com/1992-1999-91/)
-   -   ICM Swap? (https://www.gmforum.com/1992-1999-91/icm-swap-205239/)

beakah 07-29-2004 06:54 AM

ICM Swap?
 
I've been in diagnosis mode with a loss of power/bad hesitiation when accelerating, and occasional no start after the car is warm. It would turn over, but I'd have to wait 5 minutes for it to cool. Something heat related....like the ICM?? It hasn't been as bad as of late, which is why I've been in the mode for 2 months. I have access to a 92 SE. Can I take the ICM off that car and put it on mine? I have a 95 SE. I've already done ths with the MAF sensor, and that wasn't the problem. Is it possible to swap the ICM's?

Also, can someone please tell me what VATS stands for? I asked my mechanical engineer buddy, and he had no clue??? :oops:

beakah 07-29-2004 09:46 AM

Yes...it did stall on me while driving a couple times, but not recently. It would not start for me either on a couple different occasions after I went into the store for 5 minutes. I came out and it would not start...it would crank but no start. I had to wait a while then it started.

Will a bad crank sensor set a soft code?
What exactyl is a soft code?

beakah 07-30-2004 06:35 AM

Will a bad crank sensor cause a loss of power under load/acceleration? How about a clogged cat or a failing ICM?

You guys and this sight are legendary!! :D

DeathRat 07-30-2004 11:20 AM

Re: ICM Swap?
 

Originally Posted by beakah
I've been in diagnosis mode with a loss of power/bad hesitiation when accelerating, and occasional no start after the car is warm. It would turn over, but I'd have to wait 5 minutes for it to cool. Something heat related....like the ICM?? It hasn't been as bad as of late, which is why I've been in the mode for 2 months. I have access to a 92 SE. Can I take the ICM off that car and put it on mine? I have a 95 SE. I've already done ths with the MAF sensor, and that wasn't the problem. Is it possible to swap the ICM's?

Also, can someone please tell me what VATS stands for? I asked my mechanical engineer buddy, and he had no clue??? :oops:

Yes swapping the ICM's is possible....I've done a 96 Regal Series II swap into a 92 SE myself.


Originally Posted by beakah
Yes...it did stall on me while driving a couple times, but not recently. It would not start for me either on a couple different occasions after I went into the store for 5 minutes. I came out and it would not start...it would crank but no start. I had to wait a while then it started.

Will a bad crank sensor set a soft code?
What exactyl is a soft code?

Yes it can set a soft code.....
a soft code is a code that is set into the ECU when something go against the preset parameters. After "X" number soft codes, a hard code will be set. A hard code is usually set when the parts actually fails. A soft code is when a part just acts up but doesn't fail entirely (IE a hic up or brain fart). A soft code CAN set off the SES light, but only temporarily though. The SES light will not stay on longer than the problem is apparent usually or until the vehicle is restarted.

DeathRat 07-30-2004 11:22 AM


Originally Posted by beakah
Will a bad crank sensor cause a loss of power under load/acceleration? How about a clogged cat or a failing ICM?

You guys and this sight are legendary!! :D

A bad crank Sensor will just not allow the veicle to start, as it would not send a signal to the ICM to tell it which stroke the engine is on.

Loss of power can be caused lotz of things like: clogged Cat, clogged fuel filter, fouled spark plugs, clogged air filter, high resistance in the spark plug wires, etc....

DeathRat 07-30-2004 11:33 AM

VATS can be related to your problem too, thus not allowing you to restart the car. VATS is the Vehicle Active Theft Deterent System. It is not an alarm system, but does allow ONLY the user with the proper ignition key to start the vehicle.

VATS keys consist of 15 different resistors impregnated into the keys themselves. One common problem has been when a VATS resistor gets worn down, it can lose it's contact to the it's coresponding reciever insider the ignition cylinder. Unfortunately though, the only way to correct this problem is to replace the VATS Module/Transponder & Ignition Cylinder, including get two new keys as well.

beakah 07-30-2004 12:42 PM

Thanx alot Deathrat....invaluable information :)

beakah 08-10-2004 07:01 AM


Originally Posted by jr's3800
You may need to get a scantool on that car as sometimes they will have some codes that will not set the ses light off...

Also is sounds like its possible that you could have a bad Crank Sensor... Does the car stall while driving? Fail to restart untill it has cooled off?

The 95 Model year Bonneville was an odd one for sure... The failure rate of the PCM is on the bad side.. The ICM can also fail..


Just an update on this...
I've replaced the ICM and coil packs with Delco replacements. I've replaced the alternator and also took apart and cleaned the throttle body. All tune up items have been completed: new fuel filter, plugs, wires, PCV, O2 sensor. This work occured at the end of last week (Thurs-Fri). Car was running just fine with added performance until this morning....on the way to work today, the car stalled with no indication....again....just flat out stalled. I coasted to the side of the road and tried to start it....of course I could not start it and had to wait approx 7 minutes. I automatically thought of this post and the crank sensor....but the damn SES light is not coming on.

I guess my question here is if the SES light is not coming on, and this problem has occured on more than three times.....could the ECM be bad??? Isn't it true that a light should be coming on??? If in fact it is the crank sensor???

HOW DO YOU KNOW if your ECM is bad??? How do you know if it is functioning properly???

I will be taking it to my mechanic this week....will have him run codes and do a pressure test to see if the cat is clogged...but it doesn't make noise, and has never been glowing after a long period of highway driving....

I just don't want to be replacing these sensors and everything else if the ECM is the culprit....[/b]

BonneMeMN 08-10-2004 12:53 PM

Only way to test your PCM is to swap one in. The light doesn't come necessarily come on either as it has been stated.

Don't pay someone to pressure test the cat, it wouldn't be causing these symptoms.

kerker 08-11-2004 02:11 AM

My car use to stall unexpectly and it was the Crank sensor, no SES light would come on.


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