Hello,

I have a '98 C1500 5.8L that has started going into tamper mode. I have found numerous forums that talk about how to bypass the VATS system but we're having an issue of which I cannot find a fix. We followed the procedures and cut the yellow wire and measured the resistance between the key-side of the yellow wire and the orange/black wire...got nothing when the key is in the "On" position. All of the information I have found indicates that we should see an ohms reading from which we can make a resistor...problem is we are not seeing anything. When we measure from the ECM side, we get around 3000 ohms. I found one post in a forum where someone had this exact same problem but a solution was never suggested. So now I'm thinking the problem may be the ignition switch but I dont know how else to verify that. I know an ignition switch is about $100 and I'd rather not go that route unless I am sure of the problem.

Any help would be greatly appreciated!

 

Vats resistors are not in the ignition, they are on the keys. Put the probes on either side of the little black square on the two little wires and you'll get your resistance. It sounds like the sensor ring is failing or the wire going to it is breaking. A good lock smith shop will have the reader to simply put the key in and tell you what VATS key resister it is and can rekey an ignition cylinder to match your key then install it for you. Or Ohm the key and install the proper resistor to bypass the security system.

 

Hello,

I am wondering if you solve the problem, i have a bit the same problem on a Chevy Express 2500, 2005 and it is killing me.
Randomnly the van doesnt start even if it crank well, most of the times after I parked it for 10-30 minutes.
Randomnly the van stall while driving. (Kind of dangerous)
Every time it happen, it doesnt start if I crank it right after, or 1 or 2 minute after, but ALWAYS start if I wait 10 minutes and start back. (passlock learning procedure???)
Note that when it is not starting it is not hesitating at ALL, and when it does start after it start right on easily and sharp-clean.
I have seen the security light 2 or 3 time but the problem happened 50 times since 2 years. more and more often.
I have unplugged and plug back the small security wire on the key cylinder and now the security light is always ON. And van is starting anyway even with the light on.

Thank for your help and time!

 

Check your fuses with volt meter, see if your getting the same voltage across both pins of fuse. wiggle them / pull them in and out a few times. My issue was in the kick panel. Best of luck!