Security Light and Starting Trouble

This car will start 90% of the time fine. But some times it will not start at all. All of the electrical systems seem to be working fine. I have found that if I wait and try later it will usually start. Also I have noticed that the security light on the dash is sometimes on. Is this a problem with the chip in the Ignition Key or something wrong under the hood? How can I diagnose this problem? Any help out there?????????

Since you did not tell us what year your car is,it is hard to give you a definate answer.
But since you are asking about the chip in the key, I'll assume you have a VATs security system.
You can go under the dash and find the VATs connector (black connector with 2 white wires) near the base of the column.
Using an Ohm meter, check the resistance of the column end of the wires with the key in the ignition and moving the column up and down (if you have tilt) and turning the key....if the meter shows open at any time, the wires to the lock cylinder are broken and the cylinder will have to be replaced...also you will have to have a new key cut with the same pill ID# as what you had. GM dealer can read your old key and give you the correct number.

It is a 1999 model. I greatly appreciate the Info. I will check this.

I got a 93 Bonneville SE and the security light comes on after about 5 minutes of driving, but there is nothing wrong with starting the car or shuting it off. Anybody know how to fix this problem??? I tried two different sets of keys and the light still comes on....

My 97 does this. The light will come on and stay on for sometimes 15-20 minutes. Usually it goes off after like 5 min. It always starts fine but the stupid light shines in my face for no reason.
Rob

My car does the same thing, it started 5 min before and i drove to the store went in and then came out and nothing. I have a 93 bonneville, the security light comes on and just blinks just when i turn the key, if anyone can help it would be greatly appriciated. I also heard that there is a way to bypass VAT's so if there is any help people can give to me i say thank you now.

You can go under the dash and find the VATs connector (black connector with 2 white wires) near the base of the column.
Using an Ohm meter, check the resistance of the column end of the wires with the key in the ignition and moving the column up and down (if you have tilt) and turning the key....if the meter shows open at any time, the wires to the lock cylinder are broken and the cylinder will have to be replaced.

This sounds very similar to the problem I am having on my 97 Olds Achieva (2.4l quad4). My problem is that, since it got really cold, it fails to start at all now. My security light is on and stays on. Other threads have stated waiting for the security light to go out and then start the car, but mine doesn't go out.

I found the connector you mentioned, mine has 1 white, 1 light yellow, and one black. This attaches directly to the ignition cylinder. With an ohm meter, I have checked the resistance and here are my findings

white to black - 60K ohms
white to yellow - open
yellow to black - open

I am not excatly sure I tested it properly as I disconnected it to test. Could you clarify your test?

I have already replaced the coils, ignition module, plugs, crankshaft sensor and tested for broken wires and I still get no spark. I had my code scanner indicate a bad crankshaft sensor, which is why I replaced it. My code scanner now reports no problems, but it will not start.

GMMERLIN you got it right

This sounds very similar to the problem I am having on my 97 Olds Achieva (2.4l quad4). My problem is that, since it got really cold, it fails to start at all now. My security light is on and stays on. Other threads have stated waiting for the security light to go out and then start the car, but mine doesn't go out.

I found the connector you mentioned, mine has 1 white, 1 light yellow, and one black. This attaches directly to the ignition cylinder. With an ohm meter, I have checked the resistance and here are my findings

white to black - 60K ohms
white to yellow - open
yellow to black - open

I am not excatly sure I tested it properly as I disconnected it to test. Could you clarify your test?

I have already replaced the coils, ignition module, plugs, crankshaft sensor and tested for broken wires and I still get no spark. I had my code scanner indicate a bad crankshaft sensor, which is why I replaced it. My code scanner now reports no problems, but it will not start.
Now put the key in and see what you read measuring the ignition swith side of the circuit.

There are 3 or 4 different resistance values they use. Okay, I just measured 4.7K ohm on my key. I would expect to read that at the connector while moving the wheel through its entire range of motion. You are looking for an intermittent open.

If you find a problem, you should be able to put a standard 1/8 watt resistor across the connector.

YMMV

Now put the key in and see what you read measuring the ignition swith side of the circuit.

There are 3 or 4 different resistance values they use. Okay, I just measured 4.7K ohm on my key. I would expect to read that at the connector while moving the wheel through its entire range of motion. You are looking for an intermittent open.

If you find a problem, you should be able to put a standard 1/8 watt resistor across the connector.

YMMV

FYI, I have PassLock I not PassKey. I did further testing. I get a constant 29.5K ohm from white to black. Black is frame ground. There is 10.5 volts on the white wire when I turn the key on. Initially, I get 29.5K ohm from the yellow to black wire once the key is turned on, but then it slow increases about 200 ohm per second after that. Once the key is turned off 'yellow to black' reverts to open.

This car will start 90% of the time fine. But some times it will not start at all. All of the electrical systems seem to be working fine. I have found that if I wait and try later it will usually start. Also I have noticed that the security light on the dash is sometimes on. Is this a problem with the chip in the Ignition Key or something wrong under the hood? How can I diagnose this problem? Any help out there?????????

The security light disables trying for 3 minutes or 5 minutes. The light turns on when the wrong resistance is read 3 times in a row when you rotate the key to start.

Try rubbing the key contacts with a rubber pencil eraser to remove corrosion (or very light emery cloth). I have had keys get goop on them from my pocket. Service manager told me once about a guy who got cake icing into his pocket at a birthday party and couldn't start his car from the icing he carried into the key cylinder on the key.

Try the resistances from this website. One should be your key for a 99 Buick LeSabre. People have commented a little above the nominal rating works more than too low.

https://usautomotive.co.uk/tech/Anti-theft.asp