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John, Master A.S.E Automotive technician
Category: Chevy
Satisfied Customers: 9176
Experience:  A.S.E MasterTechnician A1-A8 w/L1,38 years experience General Motors Master Technician
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1990 chevy cavalier rs: computer chip..the anti theft system

Customer Question

1990 chevy cavalier 3rd computer chip put in now will not start because of the anti theft system need to reset the antii theft system
Submitted: 9 years ago.
Category: Chevy
Expert:  John replied 9 years ago.


There is a system relearn process for the anti-theft system,I am sendind it.

There is a 30 minute programming procedure tha t does not require a scan tool.
1.Turn the ignition switch to the START position,then releaseit to the ON position(the engine will not start).
2.The"Security" light should be ON.After 10 minutes,it should turn OFF.
3.Turn the ignition switch OFF & after five seconds,repeat step 1 & 2.

When this proceedure has been completed 3 times,turn the ignition switch OFF.The control unit will exchange the correct command during the next start-up attempt.
If programming is not completed correctly,either there will be no theft protection or the system will lock in anti-theft mode & the engine will not start.
Try the programming proceedure again.Note this will not reprogram key recognition,only the information transmitted on the Class 3 data link.
If there is a problem with the system the proceedure may not relearn.

Customer: replied 9 years ago.
Reply to john's Post: I did the procedure once and the car cranked will it be alright or should I still do twice more?
Expert:  John replied 9 years ago.
This procedure should be done from start to finish ,with no exceptions.
Customer: replied 9 years ago.
Reply to john's Post:

So even though the anti theft light is no longer on but the battery light is I should do the procedure twice more do you think that will cut the battery light off? I am going to accept I just want to make sure I do everything right I am a woman working on a car! But that is life, I really appreciate your help I wish I could pay more but I can't. Please answer this and I will accept thanks again

Expert:  John replied 9 years ago.
The battery should go off after the engine starts ,AFTER the complete relearn cycle has been completed.If there is another problem with concerning the battery light(cluster problem,alternator,wiring) the battery light will probably stay on.
Customer: replied 9 years ago.
Reply to john's Post: OK I am going out to do this 2 more times the car has been driven so should I do the procedure 3 times or just 2 be right back for your answer.
Expert:  John replied 9 years ago.
Start at the first step & follow it through to the end. 30 minute process
John and 2 other Chevy Specialists are ready to help you
Customer: replied 9 years ago.
Reply to john's Post: Thanks I am doing that now have a wondeful evening.
Expert:  John replied 9 years ago.
I hope you do also have a good evening & please visit JA again.