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It took me longer than most, but recently I encountered the infamous VATS Security light problem that prevents the car from starting. I've been through Shoebox's write-up about it (Thank you Shoebox!) and it seems fairly straightforward. I've ordered a bypass unit to try first, and have some resistors as a backup plan. My questions is this - will my wires ('97 Z28) be the same as his which is a '95?
Shoebox has the system wiring diagram on his site, and it notes that it is also applicable to 93/94 in the index of wiring diagrams. The addition of the body control module in 1996 complicated things. Here's the link to the 95 wiring diagram, if you haven't seen it already:
I pulled up the 1996 factory service manual, and compared the 96 diagram (should be identical to 97) to the 95 diagram. The left side of the diagrams - up to the break in the black wire - are identical. The right side of the diagram is different because of incorporating the TDM into the BCM. The wire colors appear to be similar in most instances, but it is hard to say that you can do the complete bypass (including the simulator for the PWM fuel enable simulator for the signal to the PCM) the same as 95. However, if all you are doing is adding the resistor, the wire colors from the key cylinder to the BCM are identical to the wire colors from the key cylinder to the TDM. Should work OK. While the wire color for the fuel enable signal is the same, the terminal designation is different.
Injuneer - you are awesome, as always. I downloaded it. My stupid Haynes manual didn't have that particular schematic for whatever reason. My plan is to start by trying the bypass module I ordered, which is here: https://smile.amazon.com/Timers-Shop...s%2C391&sr=8-3
If that doesn't work, I have a backup set of resistors to place on the VATS side of the wiring, and bypass the ignition wires altogether. I'm thinking I should be able to put an Ohm meter on those wires connecting to the VATS module, that will give me the required resistance needed. Because I highly doubt my keys are emitting the correct resistance anymore. Am I on the right track?
Measure the resistance directly on the key. Resistors generally don't "wear out". The keys don't "emit" anything. Make sure the metal contacts on the key are clean before you measure. Measure BOTH keys, and compare the measurements to the values in Shoebox's table:
Attempting to measure the resistance across the wires leading to the VATS Module (actually the BCM = body control module on a 1997) will not tell you what resistance it is looking for on the key. You will just measure the resistance of the circuitry inside the module, which is unrelated to the key resistance it is looking for. You might even damage the BCM, because the multi-meter has to apply a voltage to the circuitry in the BCM to measure the resistance.
And just to be clear.... the VATS Bypass Module has nothing to do with the resistor in the key. That is a module that allows you to remove the black wire that runs from terminal D8 on connector C3 of the BCM, and connect the black wire to the VATS Bypass Module. That is the wire that runs to the PCM. That is usually necessary if the BCM is no longer sending the fuel enable signal to the PCM.. That is generally problem with the BCM, due to aging of the soldered connections to the printed circuit boards in the BCM.
Have you read Shoebox's description of how the VATS system works, and how the "SECURITY" light will act if the problem is the key resistor circuit? If the problem is the fuel enable signal, the PCM will set trouble code P1626. That way, you don't have to guess whether its a problem with the key resistor circuit, or a problem with the fuel enable signal.
I’m picking up what you’re putting down. It didn’t sink in until I re-read his write-up about the function being embedded in my year, ‘97’s BCM. I would now rather skip trying to use the new bypass module, and just put in the correct set of resistors based on what my keys read. I’d rather not screw with my factory wiring anymore than I have to.
It’s my understanding that my Security light is constantly illuminated and not flashing upon trying to start it. (The car is not with me at the moment.) It’s at my dad’s place and we’ll be tackling this little bugger on Friday. Ordinarily, the car’s been awesome over the years, and stored in the winter months. My dad took it out a few weeks ago and this VATS problem came up. My Camaro was never a daily driver, so I think I’m coming into this problem a bit later than most people.
Found the appropriate ohm readings from my keys. We ended up using 4 resistors, soldered together, then heat shrinked them. I found the correct wires underneath the dash pretty easily. (They were the same as Shoebox’s wiring diagram.) Once we connected our resistors, the car fired right up.
Once again, the wealth of info on this forum has saved my bacon for the umpteenth time.
08-21-2019 | 07:08 AM
I downloaded it. My stupid Haynes manual didn't have that particular schematic for whatever reason. My plan is to start by trying the bypass module I ordered, which is here: https://smile.amazon.com/Timers-Shop...s%2C391&sr=8-3
