c4 vat system override

[Scott S.]

93' coupe that starts/won't start....starts again/won't start...etc....Was told it was the vat system to blame. I see where there is an vat override for 86-89 models but cannot seem to locate one for the 93. If not available, any suggestions on a remedy? This gremlin is driving me nuts.

[Jimmy P.]

Re: c4 vat system override

Scott,
if you still want to try the bypass option. I found this one at Ecklers. They list it as VATS CODE 8, 1986-96. Part # 25-124067-1. Their alt part #A9133-8 for $27.19. The module pictured below plugs into the wiring harness. You'll need to have a GM Dealer measure the resistance on your key to send the code number (1thru15) with your order. Other vendors may also have this, ecklers was the first to pop up. I remember installing one of the these years ago on my 86'.
hope this helps😊
Regards,
Jimmy

[Scott S.]

Re: c4 vat system override

Thanks so much. How big of a "witch" is it to install?

[Keith B.]

Re: c4 vat system override

Before trying all that try cleaning your key and cylinder. If it's dirty or wore out it will give false readings

[Jimmy P.]

Re: c4 vat system override

From what I remember, it was very simple to do on the 86. Just followed the simple directions that came with it. It was located up under the dash above the pedals. Unplugged the connector and plugged the bypass jumper in as directed. Not sure about the 93 though. Never had a problem with doors etc. afterwards. I did keep all the packaging and directions with all the car's documents. Told the next owner about it, so he would know it was there. Would need to remove for any future judging though. System must be functional for that.

[Scott S.]

Re: c4 vat system override

Did that and it helped for a while. Had to replace the entire key assembly a couple of years ago and not sure it that may be part of the over all problem now. Would like bypass entire system. Lays down at the most inconvenient times! Thanks for the response.

[Joe L.]

Re: c4 vat system override

Did that and it helped for a while. Had to replace the entire key assembly a couple of years ago and not sure it that may be part of the over all problem now. Would like bypass entire system. Lays down at the most inconvenient times! Thanks for the response.

Scott-------


Generally, if the VATS system is the problem there will be a no start----PERIOD. No crank, nothing. However, I suppose it's possible that a VATS problem could manifest itself as you describe.

You don't need to have a GM dealer measure the VATS value from your key. Simply use a VOM meter to measure the resistance of the pellet on the key. The VATS code can then be determined from the resistance measurement. Your factory service manual should have a table relating resistance to VATS code or you could probably find it on the internet. It's VERY simple to do.

[Scott S.]

Re: c4 vat system override

Joe, I will check with him. For clarity are you looking for orange letters BLACK FACE or orange letters GREY FACE? I don't recall what years were black what were grey. I am in the Cincinnati area. You?

[Scott S.]

Re: c4 vat system override

Sorry, disregard previous post. Sent incorrectly.