I have a 92 Convertible. My tech is telling me I need a new ignition and that I have to get the new keys' chip coded. My current key doesn't have a chip in it. Do keys for the 92 have chips?

 Hmmmm...if your current ignition key does NOT have the "chip", or pellet, and the car will start, then you do not need to replace the ignition switch with one that takes the chipped key.
Why does he say the ignition cylinder needs to be replaced?

My car was showing all the symtoms of a bad starter. Intermittent starts. When it wouldn't start it wouldn't crank at all. I replaced the starter and battery byt still have the same problem. A neighbor recommended I talk to a GM tech he knew.

Straight from the FSM in the  ECM Code 46 section:

"Diagnostic Aids:
  With the ignition "ON", the security light should be "ON" for 2 seconds then turn "OFF". If the security light stays on for more than 2 seconds with the ignition "ON", there is a PASS-Key problem".

So, does the security light stay on for more than 2 seconds when it won't crank? If so, your mechanic is on the right path. If it doesn't, (security light goes off after 2 seconds) he isn't. Ie, it's not the "key".

You can also query the CCM by jumping  ALDL A&G,  and using the DIC buttons to toggel the diagnostic functions that read out in the speedo / odometer.  (This is a very powerful diagnostic aid built into every 90-96 C4. Learn to use it.) Go to test 1.3,"Display CCM Inputs Status", ID #01 "PASS-Key Fuel".  "1" = Enabled. "0" = disabled.

Learn how to use the CCM diagnostics, and carry a jumper with you. Next time it won't crank, put in the jumper, and push the buttons. Shouldn't take more than 60 seconds to ascertain if it is the PASS-Key or not.

There is also a starter interrupt relay controlled by the CCM. I am not aware of it being a common C4 maladie, but this is reportedly a recurring problem in C5's.


I wonder if your "mechanic" knows about the CCM diagnostics? Or even the security light staying on?

Thanks to all who responded.

Hate to be a pain but.....There's an aftermarket alarm installed on the car. I inherited the car from my dad and don't know too much about it other than the paperwork he had. His records don't show anything about a new alarm being installed so I'm thinking it was done before he bought the car. From my research I know VATS had some issues. I'm wondering if it crapped out and, instead of purchasing a replacement, they just bypassed it and put the aftermarket alarm in. This could possibly explain why my key isn't chipped. If I purchade a replacement ignition will I have to completly install it to see if it work? Or does it need to be grounded by the steering column?

Let's start at the beginning:  Turn the key to IGN, and watch the SECURITY light. Does it come on for 2 seconds and go out,   does it come on and stay on, or does it not come on at all?

If the SECURITY light stays on, there is a problem with the PASS-Key system.

PASS-Key interrupts both the starter AND fuel delivery. Many aftermarket alarms that also have Remote Start utilize fairly simple bypasses to trick the CCM into thinking that a key is in the ignition, or it won't run from a Remote Start command. The CCM reads the key, and if correct, allows starter engagement by closing the Starter Interrupt relay, and allows fuel delivery by sending the ECM a signal for "Fuel Enable". This is the CCM test  I described above. It would be unusual to find a PASS-Key bypass on a NON-Remote Start alarm system. Unless it was put there specifically to bypass the factory key and tumblers.

If your key does not have a pellet, the Pass-Key system may be bypassed. Look in the vicinity of the wires coming out of the steering column. The pellet wires are very small, usually in a white cloth covering, and have their own 2 or 3 pin connector.  If they are disconnected, try to locate the car-side of the plug, and you should find a non-stock looking kluge of a resistor stuffed into the car-side connector.

If the ECM is not receiving the fuel enable signal, it will set a Code 46. This can be checked with a paperclip by shorting ALDL A&B, turn on the key, and watch the Service Engine Soon light.


If the Security light goes out after 2 seconds, and there is no Code 46 in the ECM, it is not the key, PASS-Key system, or anything related to the CCM causing your no-crank. It could  be the Starter Interrupt Relay I mentioned in my earlier post, or something to do with the aftermarket alarm, or starter, battery, or cables.

Again: What Is the SECURITY Light Doing upon Key-on?  You have 3 choices. Post up what it's doing, and we'll go from there.

While researching my answer for the posts above I learned some stuff about the PASS-Key system. The key resistance is learned by, and the value stored in the CCM. Once a certain resistance is learned by the CCM, it can never be changed. One certain resistance is "in there" for life of the CCM or vehicle.

 I was astonished to learn how crudely the proper key "resistance" is determined when a key to measure is not available, and where the CCM is not replaced, but has been previously programmed with keys. Ie, at the factory during vehicle assembly. In other words, a vehicle that's been in service but now has no keys.

There is a device called the "interrogator". This device is inserted into the key wiring connector at the base of the steering column. The operator puts the device on "01" and attempts to start the car. If no, there's a 4 minute timer that begins a countdown. (Remember. The system does not allow another start for 3 minutes). When the timer counts down, the red light turns off, and the operator turns the dial to "02" and attempts another start. Wait for timer, and repeat. If it happens the CCM is programmed with code #15, this process would take an hour. How efficient.

I suppose one could also get a DEI bypass resistor kit which contains one of each resistance, and try them one at a time, 4 minutes apart until it cranked and started.

But How freaking crude. That there is no way to query the CCM for the key resistance it's programmed for. Probably a security thing. No way for a thief to make the query, and supply the proper bypass resistance from his bag of tricks.

The system is fairly sophisticated.




|UPDATED|6/13/2014 8:52:11 PM (AZT)|/UPDATED|

The security goes out when you turn the key forward. But the car still won't crank.