Removing ECM for VATS disabling

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Sep 1, 2005 | 12:30 AM

ChandlerL

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From: Valley Cottage NY

Removing ECM for VATS disabling

91 C4-- I need to remove the ECM for sending to Ion at Madz28 (based on forum recommendation on someone else's thread)

He provided me with some basic instructions but it would be great for something a bit more thorough. I'm just starting to get into working on my own vehicle and I'm a bit nervous about the process. I want to be sure I'm doing it all correctly.

First things first, I need to disconnect the battery, correct? And the ECM module is inside another module underneath the driver side dashboard?

Ion told me I'm looking for a blue module which is what I need to send him.

Finally, what tools to I need? Wrench for battery, and philips screwdriver?

Hopefully I won't send him my transmission by accident.

P.S. I'm disabling the VATS because about 6 months ago it started to act hokey-- Put the key in, turn the ignition and the SECURITY light lights steady (doh!). Wait 3-4 minutes (dum-de-dum). Try again- starts.. It slowly got worse where I had to try over and over again (record was about 6 tries x 4 minutes). Now it's completely stopped working (SECURITY light always lights steady when key is tried-- no start, no crank) VATS needs to go away now.

Last edited by ChandlerL; Sep 1, 2005 at 12:33 AM.

Sep 1, 2005 | 12:46 AM

jabez

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From: Milpitas ca

hard to understand what you are saying. You are sending him the chip in the ECM?

Sep 1, 2005 | 12:34 PM

vinnies87

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From: Magnolia Mississippi

St. Jude '03-'04-'05-'06-'07

Good question: The whole ECM unit, chip for programmming, what exactly. If your removing the whole ECM, email me, I have a doc with pics that will take you step by step.

Sep 1, 2005 | 12:58 PM

Team Owner

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From: Phila., PA burbs

You could simply follow the wire leads back from your ignition to the harness under your driver side hush panel. You can then wire in a resistor of the proper value (you can get this by checking the resistance across the pellet in your key) across the two wires that go into that harness. This will cost you about $0.39 or you can buy the kit from Madvet for a lot more. This will eliminate your VATS problems and eliminate the need for the chip in your key.

Sep 1, 2005 | 07:00 PM

ChandlerL

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From: Valley Cottage NY

I'm uncertain whether I'm removing the whole ECM. I suppose it wouldn't hurt to send him the entire unit to be sure. He mentioned that he needed just the blue module to reprogram it to remove VATS. Is the blue colored module just the ECM or is that the entire unit?

Sep 2, 2005 | 12:01 AM

jabez

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From: Milpitas ca

Quote:

Originally Posted by ChandlerL

1. I think your ECM is under the hood on the driver side. I thought 90-96 vettes have their ECM located there. Its a black box right over the battery I think you said you have a 91.

2. The Blue Module ...sound like he is talking about the chip located in the ECM. It is blue and is like a memory chip in your computer.

3. If he is reprograming the the Chip you don't need to send him the ECM.

4. No special tools are need to to unhook ECM and removing the chip. First time it took me an hour and half to figure out how to do it. The second time about
15 minutes.

Last edited by jabez; Sep 2, 2005 at 12:03 AM.

Sep 2, 2005 | 12:38 AM

jfb

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From: Cincinnati, Oh USA

99% of thefts are done by bashing the column and jumping the ignition. VATS is what prevents this kind of theft, so I recommend that instead of bypassing VATS, fix it! Most likely the contacts in your ignition switch tumbler that make connection to the key pellet is worn and not making reliable connection. The cure is to replace the ignition tumbler which has new contacts. You can prove this is the problem (when it won't crank) by removing the hush panel above drivers feet and finding the two wires from the steering column that go to a 2 pin connector. Unplug the connector and insert the ign key, then measure the resistance across the wires from the steering column. It should measure the same as the pellet. If over 13k ohms, you need a new tumbler. You can temporarily bypass VATS until you can schedule a replacement by clipping a fixed resistor the same value as the pellet across the 2 wires that go into the wiring harness (goes to VATS module). A resistor from Radio Shack will work. Keep in mind that the starter can also be kept from cranking by the clutch safety switch (gear selector switch if automatic) and this switch can be jumped to see if that is the cause.

Sep 9, 2005 | 07:24 PM

ChandlerL

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From: Valley Cottage NY

Quote:

Originally Posted by jfb

99% of thefts are done by bashing the column and jumping the ignition. VATS is what prevents this kind of theft, so I recommend that instead of bypassing VATS, fix it!

Can't say I disagree with you on this. I am wary about it as well-- I'd rather it be working. It's just that I'll need to pay for a tow to a repair shop in addition to the repair. I just moved to this area (Valley Cottage, NY right next to the Palisades Center Mall-- 20 miles North of NYC) and do not know any reputable repair shops-- I'll have to check the yellow pages

I'm being convinced that's it worth doing anyway.

btw, you mentioned that a resister pellet from Radio Shack can work as a temporary solution however how does one ascertain the resistance of the pellet on my keys?

Last edited by ChandlerL; Sep 9, 2005 at 07:35 PM.