Like most GM owners, I've had my share of problems with the Passlock system, both on my Alero and my older Cutlass. Many people have the dealer "fix" it, only to have the same problems return later. My dealer says there is no permanent fix, but after some research, I've found one.


GM Truck Group UI Bulletin #26 describes a method to disable the Passlock system to allow for the installation of a remote starter.The procedure can easily be modified to work for a GM car. Here is a link:http://www.gmupfitter.com/publicat/bull/bull26.pdf

I also have found an article that explains how Passlock works, which will help in your troubleshooting. You should read this before attempting to fix a Passlock problem. Go here:
http://motorage.search-autoparts.com...09/article.pdf

The procedure calls for installing a switch in the Passlock circuit that allows you to disable it while the engine is running. The car will interpret this as a failure of the Passlock system, not a theft attempt, and will go into a "fail-enable" mode.The Security light will come on, and stay on, but Passlock will not be active. The car will start with any key that turns the ignition cylinder.


The security light cannot be turned off (but read to the end) while the car is in "fail-enable" mode. If you go to a shop and get all your OBDII codes read, you will have a Passlock failure code. If that code gets cleared, then Passlock will be active again, and you will have to hope you can get the car started one more time, to enable you to flip the switch you installed, and cause it to go into "fail-enable" mode again. DO NOT let anyone clear all your codes after doing this procedure! The GM procedure says that disconnecting the battery will clear the code, but I had it disconnected for 1/2 hour and it didn't cause any problems.


There is another method of bypassing the Passlock system. If you feel comfortable doing a little soldering, it's not very hard, and only takes about an hour (less time than I've spent sitting watching the security light flash!). Go here for the procedure:http://www.automotiveforums.com/t698...k_systems.html
Be patient, the page takes a little time to load.

I just did that today, and it seems to work pretty well so far.


Following the GM bulletin will result in having the security light on all the time. I didn't like that,so I removed the instrument cluster by removing the two screws in the black plastic cover around the gauges. That piece will then pull out. Disconnect the trip odometer button, and set the piece aside.


The cluster comes out by removing the four 7MM screws at the corners. It may look like it will not fit out the hole in the dash, but it will. Unplug the connector, and take the cluster to the bench.


Remove the back of the cluster by prying up all the tabs on the back(not the ones by the gauges). You will have to pull (gently!) the circuit board for the PRNDL lights off a little post to remove it all the way.


The main circuit board can be removed by prying it off its electrical connections. Find the LED for the security light (mine was marked D14). You can break it off with pliers, or unsolder it like I did.


Assemble in reverse order, remembering to put the PRNDL circuit board back on it's post. Now, when you start the car, the security light will never come on.Edited by: Iflylow

 

Just to let everyone know, I used this fix to bypass the Passlock on my Daughters car. Worked like a champ.

 

is this method the same for passlock 1 systems I have a 97 achieva





thx

 

I don''t know if the adding resistors method will work for the Passlock one system or not, I''m really not familiar with that one. However, read the article in the original post, it does talk about Passlock 1, so maybe you can figure it out.


do you have a chip in your key?

 

nope no chip.


I cut the wire today and put a toggle switch in to try it out.. if it works great.. if not ill try the resistor. and if that doesnt work.. solder the stuff back together

 

I would recommend the resistor, because the toggle switch will only work until you disconnect the battery or your codes get cleared by someone. Then you will have to hope the key will work one more time.


The resistor is a permanent fix, regardless of how worn out your ignition cylinder becomes. You may have to solder two resistors in series to get the correct resistance. Radio Shack has them cheap, I think I paid $1 for ten. You don''t have to get the resistance exact, within 100 ohms worked for me.

 

I have a 2001 impala that is having the same passlock problem. Could someone please email me the fix to smb92@yahoo.com. Thanks

 

2002 Chevy Express G1500 van, 305cid, auto. would not start, mechanic said new key cylinder and key neededand i did install them. still would not start due to PassLock programming.mechanic instructed to leave key in RUN position for at least 20 minutes and i did so. van started and continued to start without fail for 2 weeks. now van will not start and is exact same symptoms. cannot figure out how brand new key cylinder and brand new VIN matched key is failing again after that fixed the problem before. corrosion in wires? engine computer failure? **please e-mail fix.** have read literally hundreds of stories about PassLock failures that strand people, cost lots of money. any chance GM will recall this crap? genuinely thinking about replacing drivetrain with manual tranny and carburetor intake, etc. NO MORE ELECTRONICS! Thank you for any help!


314802@comcast.netEdited by: AMSOIL314802

 

Was the security light on during the failed start attempts? If not, you do not have a Passlock problem. The Passlock wiring is very sensitive, like you said, if there is some corrosion or a loose connection, you will have intermittent problems.


Usually a BCM (Body control module) computer failure will show other symptoms in addition to a "no start" condition.


I''ll send the service bulletin.

 

I have a 99 Chev S10 I owned since 1999 when I bought it with 6800 miles on it. At that time I put in a Kenwood CD AM/FM CD unit. It now has 88,600 miles on it. About a month ago I, the Security light, battery light, ABS light, seat belt light would come on occasionally while I was driving. The water temp gauge goes to zero, and the fuel gauge indicates empty, and the gear indicator disappears ( the letters are there). Sometimes this goes out by itself while I''m still driving. Usually the Security light goes out and all the gauges resume normal operation on restart. I should also say that for some time I have been having to give the shift lever a litlle extra nudge to get it into Park or the ignition would not turn off power fully ( the battery light would stay light when I shut the truck off).

Please send me the Group VI #26 Bulletin to: ''mauiman1@comcast.net''