GM Passlock '98 Sunfire

[D60]

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?

 

[D60]

Oh also can my Autel see how many "successful" attempts it has logged?

Being only ~3 years into OBD2 I don't know how much information it can provide on peripheral issues like anti-theft

 

[slacktide_bitog]

most people just bypass it

 

[GMBoy]

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.

 

[dishdude]

Check out this thread.

9

Thread 'New Cavalier starting problems'

Dec 2, 2025

Hi All,

So now that cold weather is setting in Colorado my 97 Chevy Cavalier won't start below roughly 40f. It throws the theft light in the dash and cuts fuel. GM went with an archaic and odd anti-theft system. Apparently there are magnets in the key column that engage when you turn the key. This sends a signal to the pass lock system to allow the vehicle to start. Somewhere along the lines if it gets cold it causes the system to freak out and lock you out from starting. I have used the unhook the battery method but this past morning was 14f and that didn't fix it. My dad replaced the...

• 97prizm
• Replies: 43
• Forum: Mechanical/Maintenance Forum

 

[Propflux01]

Just one of the big reasons I swore off GM cars.

 

[Timmastertech]

If the theft light isnt flashing there is a problem somewhere. Compare the magnet on the replacement cylinder to the original. Lots of cylinders out there with junk magnets and have seen a few that didnt even have magnets. Also check the cluster for antitheft faults

 

[D60]

Yeah the light only flashes when it shuts down, then stays on solid.

So, it should flash the entire time?

 

[D60]

Check out this thread.

9

Thread 'New Cavalier starting problems'

Dec 2, 2025

Hi All,

So now that cold weather is setting in Colorado my 97 Chevy Cavalier won't start below roughly 40f. It throws the theft light in the dash and cuts fuel. GM went with an archaic and odd anti-theft system. Apparently there are magnets in the key column that engage when you turn the key. This sends a signal to the pass lock system to allow the vehicle to start. Somewhere along the lines if it gets cold it causes the system to freak out and lock you out from starting. I have used the unhook the battery method but this past morning was 14f and that didn't fix it. My dad replaced the...

• 97prizm
• Replies: 43
• Forum: Mechanical/Maintenance Forum

I remember that thread but forgot how it concluded (I thought they got a new cluster) .

I think I have the same problem as @97prizm because the magnet? resistor? wasn't even installed in the tumbler housing. I simply pushed it in to place and figured it's held captive once slid into the steering column. But likely not.

This is a Standard US220L but not sure the quality is there.

 

[Timmastertech]

Yeah the light only flashes when it shuts down, then stays on solid.

So, it should flash the entire time?

yes, the theft light going out is the signal to cycle the key, should flash for 10 minutes

 

[97prizm]

I remember that thread but forgot how it concluded (I thought they got a new cluster) .

I think I have the same problem as @97prizm because the magnet? resistor? wasn't even installed in the tumbler housing. I simply pushed it in to place and figured it's held captive once slid into the steering column. But likely not.

This is a Standard US220L but not sure the quality is there.

I had to return two defective ignition from o reilys. Napa was actually cheaper and correctly made. The magnet has to be pressed into the tabs.

 

[97prizm]

I remember that thread but forgot how it concluded (I thought they got a new cluster) .

I think I have the same problem as @97prizm because the magnet? resistor? wasn't even installed in the tumbler housing. I simply pushed it in to place and figured it's held captive once slid into the steering column. But likely not.

This is a Standard US220L but not sure the quality is there.

If the magnet isn't pressed tight into the tumblervit will never allow you to reset the new ignition switch. I had this problem with junk tumblers from O'Reilly auto parts.

 

[ls1mike]

Just one of the big reasons I swore off GM cars.

It is 28 years old. Come talk to me when ANY of your cars are that old and still running.
This place is ridiculous sometimes.
It is an easy fix. Get the resistance from the key and insert a resistor into the plug and call it a day.
I ran the WS6 like that for years.

 

[97prizm]

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?

Does the original Tumbler work? If so start the vehicle then unplug the ignition. The Theft light will stay on but you will be able to bypass the ignition module. I suspect that if the battery is unhooked or dies it will trip the ignition anyi theft again. The issue is that when the ignition module gets old cold weather trips the sensor causing it to cut power. PM me if you need help.

 

[97prizm]

Yeah the light only flashes when it shuts down, then stays on solid.

So, it should flash the entire time?

"To reset a GM Passlock system (security light on, no-start condition), perform a 30-minute relearn procedure: Turn ignition to "ON" (engine off) for 10 minutes, turn "OFF" for 5 seconds, and repeat this cycle 3 times. Ensure the battery is fully charged, as low voltage can fail the process".
I didn't try it but I've read that hooking the battery to a charger while doing this can help keep the voltage from dropping.
GM made alot of wacky decisions on the Cavalier and sunfire. A set of oem fuel injectors cost more than the car is worth in many cases.

 

[Propflux01]

It is 28 years old. Come talk to me when ANY of your cars are that old and still running.
This place is ridiculous sometimes.
It is an easy fix. Get the resistance from the key and insert a resistor into the plug and call it a day.
I ran the WS6 like that for years.

The car I had wasn't 28 years old. It was less than 6. It was one of many issues this car had.

 

[The_Eric]

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.

 

[D60]

"To reset a GM Passlock system (security light on, no-start condition), perform a 30-minute relearn procedure: Turn ignition to "ON" (engine off) for 10 minutes, turn "OFF" for 5 seconds, and repeat this cycle 3 times. Ensure the battery is fully charged, as low voltage can fail the process".
I didn't try it but I've read that hooking the battery to a charger while doing this can help keep the voltage from dropping.
GM made alot of wacky decisions on the Cavalier and sunfire. A set of oem fuel injectors cost more than the car is worth in many cases.

See, that's what I'm saying: that procedure doesn't tell you to START it, but I think you're supposed to (it'll only run for ~2 seconds)

Honestly, the system is no more or less dumb than later systems. Chrysler decided to do the 4 digit PIN which is just as stupid and useless. I think most of these approaches might stump thieves for the first year after introduction, then the secret's out and they're ineffective except to frustrate mekaniks

 

[97prizm]

If I remember correctly GM only had 6-8 resistor combinations, not like ignitions today. The issue is that even if you knew the resistor value you can't order a specific one. You get what you get. I'll see if I can dig up a picture of the one I got at O'Reillys.

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.

 

[STL_G8GT]

"To reset a GM Passlock system (security light on, no-start condition), perform a 30-minute relearn procedure: Turn ignition to "ON" (engine off) for 10 minutes, turn "OFF" for 5 seconds, and repeat this cycle 3 times. Ensure the battery is fully charged, as low voltage can fail the process".
I didn't try it but I've read that hooking the battery to a charger while doing this can help keep the voltage from dropping.
GM made alot of wacky decisions on the Cavalier and sunfire. A set of oem fuel injectors cost more than the car is worth in many cases.

Reminds me of the spider injectors in my 5.7!!