Hey folks,

Apparently my only key for my '92 slid off the dash of my other car and into nowhere-land, when driving out to make a copy of it -- how ironic. I've literally torn apart the other car looking, it must've fallen out, but anyway, I appear keyless. I got a chipless test key via VIN so I can at least turn the ignition and unlock the steering column to flatbed it, but figured I'd first try to figure out what resistor to use on it.

Let me first say, I deal with automotive systems and electronics daily, so I'm not an idiot, but I do occasionally make mistakes, as will be mentioned below.

I printed out the list of appropriate passkey resistor values, found the cord, disconnected the connector, and plugged in various resistors through the back of the connector. Not getting anywhere fast, I decided to upgrade to small alligator clips and a 10K potentiometer, which I would disconnect, tweak to the right setting via fairly-accurate multimeter, then reconnect, etc.

After about 3 of these I noticed SYS flashing on the dashboard, the "security" light staying steady-on with key on. I intially read about that signifying a passkey system error, so figured maybe it meant my resistances were off or something, but to make a long story short, the alligator clips I used had shorted together inside the passkey connector.

I paid closer attention to the "starting up" process, and noticed that my "Check Engine" light doesn't come on any more when the key is on... used my ALDL computer and was unable to negotiate a connection. Tried the paperclip on the ALDL connector, and still nothing.

Soooo, while I'm combing back through the schematics to see what I might've blown up (you'd think GM might've built fault tolerance into that?) I figured I'd see if anyone here may have had similar problems with the SYS indicator. GM said they'd interrogate it and make me two new keys for about $150, which is sounding pretty tempting after a couple hours in the cold and snow. But now I'm afraid that if I blew up the CCM or something the bill would get pretty steep pretty fast at the dealer, so I'd like to try to fix my own mistake here first.

Again, to summarize:
* inadvertantly shorted the passkey connector
* no check engine light (fuses look good, I'll test continuity too)
* security light is steady when key on, flashes when key out & door ajar
* Going to try the built-in test stuff right now to see if I can read codes or VATS data via the LCD. No idea if that'll work, but if so, I'll post below.
* Battery is down to about 10v due to all my screwing around. I don't THINK this is an issue, but I'm in an apartment, and can't really charge it easily

Thanks for any help!

 

10 volts is to low. Charge the battery.

Normally when you see SYS displayed and if you could pull codes from the CCM and there are no trouble codes it indicates a low battery charge.

As far as damaging the CCM by shorting the connector for the Pass Key connector that goes to the CCM, I'd say no way did you damage it.

The ECM controls the Service Engine Soon light so my guess is the low battery is causing problems with the ECM.

You are waiting at least 5 minutes after you try a resistance value before you try a different value?

 

I did successfully get info from the CCM, which did detect the shorts and opens with the passkey resistor as expected -- which apparently are persistant errors... good to know.

However, it also pointed out a loss of serial communications (which of course instantly came back after I cleared the CCM codes). So I guess I'll try to charge the battery and see if that helps... I did test all the fuses, so I'm stumped.

 

Yeah, sounds like a plan, thanks. We'll see! Thanks for your "guess" -- much more educated than mine, I'm sure!

I'm waiting four minutes between values (as per the service manual, which is already above the three minutes suggested in the owners' manual) -- I did go through the entire set once, but it's quite possible those terminals were shorted at the time, so I'll try again tomorrow when I finally have more time.

I guess the steady-on Security light was due to the security codes set on the CCM(?) so hopefully that should be taken care of as well -- I didn't think to look. I will say that when trying the CCM "output test" (oil change light, high beam indicator, etc), many of those didn't work either... though some did. If it persists after I recharge, maybe I'll look into it further.

Thanks again!

 

Yeah, sounds like a plan, thanks. We'll see! Thanks for your "guess" -- much more educated than mine, I'm sure!

I'm waiting four minutes between values (as per the service manual, which is already above the three minutes suggested in the owners' manual) -- I did go through the entire set once, but it's quite possible those terminals were shorted at the time, so I'll try again tomorrow when I finally have more time.

I guess the steady-on Security light was due to the security codes set on the CCM(?) so hopefully that should be taken care of as well -- I didn't think to look. I will say that when trying the CCM "output test" (oil change light, high beam indicator, etc), many of those didn't work either... though some did. If it persists after I recharge, maybe I'll look into it further.

Thanks again!

 

If the CCM detects a error it flashes the SYS.

The Security Light Blinks when the door is open.
Goes out when the door is closed.

When you insert the key and turn the key to run or start the
Security light will turn on and then go out indicating the key pellet was read properly. If it stays on, it indicates the key pellet is not correct.

To pull codes direct from the ECM short pin A to B and turn the ignition on. Codes will be flashed using the Service Engine Soon lamp.

Hopefully the low battery is why you're getting comm. error between the CCM and the ECM and why the Service Engine Soon light is out.

I'm not sure what year it started, (maybe 93 I see you have a 92) but the CCM detects when the key is in the ignition. So on the safe side when you do change the resistance value, pull the key out plug in your new resistance value then put the key in the ignition turn it to on and if you guessed the right value the Security Light will go out.

 

Yes, shorting A to B got no results -- unless the bulb chose this very moment to go out I'd still wager you're right on the low voltage causing issues, especially now that I know why SYS was set. I knew it indicated an error, but didn't know those errors (ex: shorted pellet) lasted between ignition cycles.

Thanks for the tip on removing the key -- I initially did that, then got lazy since I figured "when does it really read this, anyway?" Same with actually hooking up the resistor -- I should probably unhook it for the full X minutes even though I'd "think" it would only check when you turn the key on.

Wish me luck!

 

If it were my car, I would order all 14 VATS (Yes people will tell you 15, but 1986 was the only car to use a VATS #1 key) keys from www.clksupplies.com Total cost $3.25 x 14 = $45.50

Once you got the keys, then I would place each in the ignition and see which one changes the systom. Wait 5 minutes, then do the same thing with the next key..etc.

Once you find your key, take it to Walmart, Home Depot.. and get it cut. Then, give the rest away to forum members. That way, your getting a cheap fix, your helping the forum members, and your getting your car fixed.

 

I need to turn the ignition on to know if the key works, right? Unless I'm missing something, that might be a challenge if I had an uncut blank in there.

Thanks for the source of blanks -- sounds like a great price. Hopefully I'll have a bit of luck later today, now that it's daytime again. Can't wait to get myself a garage.

 

All fixed! A combination of some electrical gremlins and finally understanding the meaning of the "SYS" stuff. Thanks for the help!