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Category: Chevy
Satisfied Customers: 26254
Experience:  ASE certified tech ADVANCED LEVEL SPECIALIST. Wisconsin certified emissions state inspector
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98 chevy malibu: Theft System light stays on all of the time

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I have a 98 chevy malibu and have been working to get it started for several days now. The Theft System light stays on all of the time and turning the key to crack does nothing. Have replaced the lock but not the switch yet. Have gone through all of the steps in clearing everything and going through the process to reset the passlock system. What's up?

Hello, I am Daniel. I may ask you questions, to better answer you. Please let me know if you have any other questions before you Accept.


Have you done the reset of on for 10 minutes and off for 6 seconds 3 times in a roll?

Customer: replied 6 years ago.
yes, twice for a total of 30 minutes each time.
do you have a spare key? can you try it?>
Customer: replied 6 years ago.
yes, I have two keys with the new lock that cost $175.00. So you think I should try the reset three times with the other key? Also the directions that came with the new lock said to do the 3 10 minute cycle thing but that the Theft System Light would go out after 10 minutes. This never happened, it always stays on.
Do it with the new key or spare key your old one may have been knocked around enough not to work any more. Good luck.
Customer: replied 6 years ago.
Tried the other key. Still no go. The Theft System light remained on the whole time. I will try some cleaner on the inside of the switch tonight and retry. Any other ideas?
All the connection need to be checked starter and battery need to be clean and tight as a poor connection will trigger anitheft. you have a new battery so it wouldnt be that. But your anittheft module will need to be diagnosed with a qualified scan tool the dealer will have one for sure only some qualified shops will have one. You can still do your own work after a scanner to diagnose is located.
Customer: replied 6 years ago.
I hear I can rent the scan tool at Autozone and read the codes. I can do this and look them up online since I have no way to drive the car to the dealer. What about replacing the switch? Where is the atitheft module? Can I just replace it?

The Passlock System is designed to prevent theft even if various theft deterrent parts are changed. Parts that can no longer be changed without the possibility of going into a tamper mode are:

  • Passlock Lock Cylinder
  • Body Function Controller (BFC)
  • Powertrain Control Module (PCM)

If any of these parts are replaced, the vehicle may start and stall for 10 minutes (Long Tamper Mode). If this occurs, the system must go through a Long Tamper Mode cycle. During this time, the THEFT SYSTEM indicator will be flashing for the full ten minutes and DTC B303 1 will be set. The BFC and PCM require the full ten minutes to complete a learn cycle. The Ignition Switch must remain in the RUN position until the THEFT SYSTEM indicator stops flashing or the cycle will have to be repeated.



So the question is which module needs to be replaced. throwing parts at it may be expensive. you could try a salvage yard.

Customer: replied 6 years ago.

I understand but my THEFT SYSTEM indicator never flashes it remains on SOLID all of the time. So what would cause that?

I will opt out for other experts to view this.

Edited by Jettadan1 on 1/13/2011 at 12:32 AM EST

New Expert here!

Did you still need help?
Customer: replied 6 years ago.
Yes, have you read my information? I just sprayed contact cleaner in the switch and am waiting for some time.
It sounds to me like you just have a bad ignition switch. THis is very common!
Test voltage at left instrument panel fuse block IPC/BFC ACC labeled fuse, PCM ACC labeled fuse. Test voltage back probed at left instrument panel fuse block C1 Natural connector terminal A7 Dark Green wire. Test voltage backprobed at ignition switch C1 6 cavity Natural connector terminal E Dark Green wire.
Test terminal contact, replace ignition switch.

Potential Causes:
Ignition Power — Ignition power supply.
Ignition Switch
Left Instrument Panel (IP) Fuse Block
Terminal Contact
Category: Chevy
Satisfied Customers: 26254
Experience: ASE certified tech ADVANCED LEVEL SPECIALIST. Wisconsin certified emissions state inspector
AMEDEE and 2 other Chevy Specialists are ready to help you
Customer: replied 6 years ago.
Got the Switch out - What a MFer. Will get a new one tomorrow. If it works you get the boobie prize. thanks.

I know... the switches are not fun to remove. Hope you went through the instrument cluster to get it out.

Let me know how it goes!
Customer: replied 6 years ago.
Replaced the swithch. Started right up and everything seems to be fine now except the Theft Security light still remains on all of the time but I can live with that. Thank you very much! And yes I did go through the instrument cluster to get it out.

Thanks for the accept!

Glad to hear it is working!

A simple ignition switch relearn procedure should take care of that security light issue.

Have a great day!