Anybody familiar with ~ 1998 Chevy PassLock systems? (Page 1/1)
FieroGT42 JAN 23, 01:23 PM
I have an intermittent starting problem. The theftlock light is on but not blinking. IIRC, thelftlock should cause it to start and then die but it doesn't even crank. Removing the battery ground fixes this for a start or three. Which part of the system has failed? :/
Monkeyman JAN 23, 10:33 PM
Theftlock is for the stereo. It has nothing to do with your starting problem. The only Theftlock light should be on the stereo as that's not an integral part of the vehicle.
FieroGT42 JAN 24, 02:52 PM
Okay, I thought the two were connected like they are on some cars. So it isn't the stereo "TheftLock", but I still think it's part of the anti-theft system that's keeping it from starting.

Edit: Okay, it's called PassLock. That's what I meant.

Disconnecting the battery fixes it. So does the theft reset procedure, which is leaving the key in Run for 15 minutes. Then it starts right up. Otherwise the solenoid doesn't even click.

The failure to start is intermittent, but if it's occurring then the car is not turning over, and in that case either of those things always works. I'm trying to research the specifics of PassLock now.. :/

[This message has been edited by FieroGT42 (edited 01-24-2013).]

Monkeyman JAN 25, 06:27 AM
Is it the Passlock or Passlock II? Does the key have a chip in it? What car/truck is it in?
cmechmann JAN 25, 08:53 PM
My wife has a 2001 passkey with the resistor chip. Same thing happened when the key contacts wore in the ignition cylinder.
I did the resistor in wire mod and have not had an issue since.
All this does is bypass the reading from the ignition lock. The key fob operation still does it's job. This is for the Saginaw collum. Round metal cover around the ignition lock assembly. If you have oval/rectangular covers or your ignition lock is on the dash, there is a different procedure for those. This is also only for the key with the chip. Passkey II has a code transponder in the key. If you have that type you need a key battery or new key.
You could also replace the ignition lock, but new keys would have to be made with the same value resistor chips.
Before starting measure the resistance of the key chip. Use a volt meter and measure the small metal strips on each side of the key chip. Make up a resistor pack out of 1/4 watt resistors to equal the with in 2%.
If you have 2976 ohms, 3025 will work.
Remove the panel under the steering collum. Also the knee plate if equiped. Look for the 2 wire connector with very fine yellow or white wires. Inside an cover that looks like heat shrink tubing.
Make sure you don't mixed them up with the airbag connector. There will be a tag near the connector for the airbag with a warning. Leave that one alone. If you can't determine if you don't have the airbag wires. Put it back together .
Put your key in the ignition lock. Measure the wire on the Passkey I/Vats connector going up the collum. If you don't get the same reading, move the key around, turn on and off, etc. To see if you can get it to read. If it is intermittent or doesn't read you found the problem. These will be very small terminals. I would take leads cut off a resistor, capacitor, transistor, ect, to stick in the connector to make it possible to measure.
Reconnect the passkey connector and try to get the car to start. To save a relearn wait later. If you don't want to replace the lock cylinder, While running. Disconnect the connector, take the resistor, you made, install the leads into the side of the connector going in the dash. I would take some heat shrink over the end to keep it together and insulate. The BCM is looking for the value when you put the key in and try to start. After on it will only give an error code for lost signal .If the BCM is capable.
So if you install the resistor while on when the BCM picks it up again it just assumes a bad connection.
You can do it off, but you are most likely going to have the BCM do the 10 min wait. That also makes it more crucial to have the resistor values close.
There are also VATS/Early Passkey devices that can be clipped to the ECM to give the ECM a clear security signal.
This is an analog signal at 30 or 50hz. 98 was a change over year after that and some of that year sent serial data to the ECM. That data is Vin specific.

[This message has been edited by cmechmann (edited 01-25-2013).]

FieroGT42 JAN 26, 05:02 PM
I don't know if it's VATS, PassLock or PassLock II. It's a 1998 Chevy Cavalier with plain metal keys. No transponder, chip or resistor on them. I've heard it uses the resistance of the key itself. If that's true, what do I measure to find the correct resistance?

I've read about the resistor trick and the other bypass modules, so I'll see what I can read on that connector. So I need to check the resistance across the pins on the key side of the plug to see if it's picking up the key correctly, and if that's the problem I'd short the other end with resistors?