GM Passlock '98 Sunfire

Dumb question - but did you make sure it's plugged in? There is not a lot of extra wire it could have came unplugged.

Next - you do not remove the key each time you cycle it - key STAYS in. Just turn it on....wait 10 min until light stops flashing then turn key off and back on w/o removing it and count another 10 mins. Then the 3rd and last 10 min take the key out...wait a few seconds and it will start the car. Also set a timer as it is that important.
Ok re-reading this you also just say ON but not START. The only reason I was starting was because it was the ONLY way I'd get a (BRIEF) flashing light -- then it returns to a solid theft light

Anyway, I'm gonna try the old cylinder today and see how it performs and causes the light to behave
 
I installed a new ignition lock cylinder in a '98 Sunfire. It was starting fine before, just mechanical problems with actually turning the key.

Trying to relearn the resistor and after four attempts, no luck yet. I've read several accounts on how to do this, but it seems little details vary.

Must I really remove the key completely after each attempt? Is 45 seconds between attempts correct? Does it matter? Ten minutes, twelve minutes, or ?? If I go TOO far -- like 30 minutes -- is that bad? I was trying to stay busy during the "ten minute" waiting periods.

On this '98 the theft light comes on solid. You can start it and then it shuts down and the theft light flashes three?ish? times. I've then been waiting 10 to 30 minutes and trying again, but I finally had to stop for the night.

The vehicle was on a power supply the entire time. The owner doesn't want a bypass (I don't know why).

I've done the ten minutes x 3 on GMT800s with new PCMs and it was easy. But these older Passlock systems seem cantankerous. If anyone has an exact sequence for the best chance of success, I'm open to it. And do I need to do something to "start over" since I've abandoned the cause for the day?
My suggestion is either Black Bear performance who can re-encode the ignition for $125.00 or install the original ignition start it then unplug it while running causing the anti theft light to stay on. Then install the new ignition and don't hook up the harness. There aren't many options. These were throw away cars, the bic lighters of the car world.
 
My suggestion is either Black Bear performance who can re-encode the ignition for $125.00 or install the original ignition start it then unplug it while running causing the anti theft light to stay on. Then install the new ignition and don't hook up the harness. There aren't many options. These were throw away cars, the bic lighters of the car world.
I spit out my coffee with that one!
 
This is Passkey, not Pass lock, right? If it's got the resistor, isn't that value stored in the BCM, which only reads the resistor through the lock cylinder? Doing relearns shouldn't be necessary I don't think. I think that 97prizim may correct in that it sounds like you have an issue with the replacement cylinder.
That's what I was thinking. My 1998 Chevy K1500 was Passkey. I know this because I (foolishly) installed an aftermarket remote start in it and became all too familiar with that system. I had to buy a variable resistor module to cheat the passkey system for the "bulldog" remote start kit. It basically came with a manual that told you the resistance value for each make/model vehicle. You dialed it in on the black box and were good to go.
 
Ok re-reading this you also just say ON but not START. The only reason I was starting was because it was the ONLY way I'd get a (BRIEF) flashing light -- then it returns to a solid theft light

Anyway, I'm gonna try the old cylinder today and see how it performs and causes the light to behave
Yes you do not start the car for the procedure. That you don't get the flashing light when performing the procedure points to an issue preventing the process from being able to initiate. I will dig deeper into this when I get to the shop.
 
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Yes you do not start the car for the procedure. That you don't get the flashing light when performing the procedure points to an issue preventing the process from being able to initiate. I will dig deeper into this when I get to the shop.
If the magnet isn't pressed in tight no amount of trying will get it to work. I had two defective units from O'Reillys. I went to Napa and the first one I got was a beefy unit with the magnet pressed in tight and correctly I might add. Made in Taiwan not China.
 
So, it should flash the entire time?
That is what Mitchell says. After attempting to start and having the engine stall due to passlock, the "key" light should be flashing constantly. If you then leave the key on with the light flashing for 10 minutes it should learn the new resistance. At that point the light goes out. Then you can turn the key off and back on to start normally.

My guess is when it flashes 3 times then goes out, the system is not getting a valid resistance reading from the cylinder at all so it won't be able to learn new resistance.
 
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Is this a customer car? Do they just need it running?
Is this the type of key or does it say PK3 on it?
key.webp


If it is like above.
Just measure the resistance across the resistor in the key. Order that resistor for a few
bucks and plug (I soldered it) it into the wiring. There were few different colors. White and Black, White and orange (WS6) and Purple and white.
What happens is the wires are small and the break at the tumbler.

If the key is a PK3 key, like below. There is a relearn procedure.
PK3.webp



Does the customer need this to work or do they need a running car?
My guess is just a running car.
No one is stealing a 98 Sunfire. If it is the resistor key, just bypass it. The car won't know the difference.
 
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Does the customer need this to work or do they need a running car?
My guess is just a running car.
No one is stealing a 98 Sunfire. If it is the resistor key, just bypass it. The car won't know the difference.
Dude, I literally told him this AND it's a manual transmission!!

He said something like "Actually they're one of the most stolen cars today." I cannot believe that, but he seemed so sure of his position I didn't want to get too confrontational. And no, he wasn't joking.

It takes all kinds......
 
FOR 2005-2012 chevrolet colorado passlock

30-Minute Learn Prqcedure
1. Turn ON the ignition, with the engine OFF.
2. Attempt to start the engine, then release the key to ON, vehicle will not start.
3. Obserue the SECURITY telltale. After approximately 10 minutes, the telltale will turn OFF.
4. Turn OFF the ignition, and wait 5 seconds.
5. Repeat steps 1 through 4 two more times for a total of 3 cycles/30 minutes. The vehicle is
now ready to relearn the Passlock Sensor Data Code and/or passwords on the next ignition
switch transition from OFF to CRANK.

Important: The vehicle learns the Passlockr* Sensor Data Code and/or password on the
next ignition switch transition from OFF to CRANK. You must turn the ignition OFF before
attempting to start the vehicle.

6. Start the engine. The vehicle has now learned the Passlock Sensor Data Code and/or
password.
7. With a scan tool, clear any DTCs if needed. History DTCs will self clear after 100 ignition
cycles.
 
Dude, I literally told him this AND it's a manual transmission!!

He said something like "Actually they're one of the most stolen cars today." I cannot believe that, but he seemed so sure of his position I didn't want to get too confrontational. And no, he wasn't joking.

It takes all kinds......
Lord in heaven above. Well I'm done with the internet today.
 
Ok well I ran to a local AZ and got the Locksmart cylinder. I suspect both Standard and Locksmart come out of the same factory as the layout of the stickers is very similar, and they're both Taiwan COO.

I was disappointed to find the Locksmart resistor kinda "clicked" into place but you could still pull it out with ease. In contrast, the existing cylinder had the piece securely anchored -- even gently prying with a screwdriver resulted in zero movement.

Here's the Standard for reference
20260207_151746.webp

In the end I put the Locksmart internals into the original housing. Now it works smoothly and the vehicle starts -- no relearn necessary.
20260207_151317.webp

Looking at the Locksmart housing (which I did not use) it looks like they do try to crimp it in there as @97prizm suggests. Here are two views/angles of what I think is supposed to be a "crimp".....?
20260207_152121.webp
20260207_152125.webp
 
Dude, I literally told him this AND it's a manual transmission!!

He said something like "Actually they're one of the most stolen cars today." I cannot believe that, but he seemed so sure of his position I didn't want to get too confrontational. And no, he wasn't joking.

It takes all kinds......
There aren't many left and you're right nobody is going out of their way to steal these things. I'd be curious how many are actually left on the roads. I haven't seen a first Gen cavalier in 20 plus years. In Colorado most of the Cavalier and Sunfires get scrapped with no parts pull. Oddly enough in Phoenix at every junkyard my dad visited they all had their fuel injectors pulled. So maybe they all ended up in Mexico and central America?
 
Ok well I ran to a local AZ and got the Locksmart cylinder. I suspect both Standard and Locksmart come out of the same factory as the layout of the stickers is very similar, and they're both Taiwan COO.

I was disappointed to find the Locksmart resistor kinda "clicked" into place but you could still pull it out with ease. In contrast, the existing cylinder had the piece securely anchored -- even gently prying with a screwdriver resulted in zero movement.

Here's the Standard for reference
View attachment 323394
In the end I put the Locksmart internals into the original housing. Now it works smoothly and the vehicle starts -- no relearn necessary.
View attachment 323396
Looking at the Locksmart housing (which I did not use) it looks like they do try to crimp it in there as @97prizm suggests. Here are two views/angles of what I think is supposed to be a "crimp".....?View attachment 323398View attachment 323397
That looks exactly like both of the defective parts that I got from O'Reillys. The crimping wasn't done correctly. Not sure how.
 
There aren't many left and you're right nobody is going out of their way to steal these things. I'd be curious how many are actually left on the roads. I haven't seen a first Gen cavalier in 20 plus years. In Colorado most of the Cavalier and Sunfires get scrapped with no parts pull. Oddly enough in Phoenix at every junkyard my dad visited they all had their fuel injectors pulled. So maybe they all ended up in Mexico and central America?
I see lots of "old" stuff around here because we just don't have rust. There is daily driven Cavalier in my parking lot at work.
 
I see them on the road regularly. The youngest one is old enough to walk into a bar and order a beer!

Cavaliers were great inexpensive cars.
I will say my Cavalier (knock on wood) out lasted my 05 neon. I expected the transmission in the neon to go 200k without much effort. It's had transmission fluid and filter changes every 40k miles like the manual says. The transmission started acting up around 150k or so. It wouldn't go into overdrive, then randomly lose the speedometer. I had the fluid changed at 150k which helped temporarily then it outright died at 156k. A rebuild kit is cheap but the labor and a rebuilt transmission is more than the car is worth. Very infuriating.
 
I see them on the road regularly. The youngest one is old enough to walk into a bar and order a beer!

Cavaliers were great inexpensive cars.
This is why my fiancé, and I still drive our 92 Cavaliers around. They are both fairly reliable and still get good gas mileage. They keep the mileage off of our newer cars.
 
Dude, I literally told him this AND it's a manual transmission!!

He said something like "Actually they're one of the most stolen cars today." I cannot believe that, but he seemed so sure of his position I didn't want to get too confrontational. And no, he wasn't joking.

It takes all kinds......
No one stole these cars when they were new and they aren't being stolen now. That said, just bypass it. I've had to do multiple passkey bypasses over the years, the early PK1 seems to fail eventually no matter what. At least they were very easy to bypass with some simple rewiring and disabling the VATS enable option in the ECM/PCM. Had to do it on both of my Camaros and just recently had to put in a bypass module in my brother's 99 Suburban due to the PK2 not working properly anymore. Its not worth the trouble of trying to chase the issue and finally fix it if you can even find it.
 
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