Question about 1998 Chevrolet Astro

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Anti theft system needs reset/relearn procedure

After replacing the vcm,( did the passlock relearn procedure), The van ran as it should for about a week.... Now every time I turn the ignition key to the start position, to start the van, the horn blows. No codes, no security lights, just the horn and nothing else. Tried leaving the ignition in the run position, and cranking the motor,( bypassed the start relay). The engine tries to run but dies, ( the same as before the vcm replacement). My gm shop manuel doesn't even mention the passlock system.

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  • wmason54 May 29, 2009

    The new computer was reflashed...As a test I reinstalled the old vcm and the the problem remains the same,( not going to be the vcm). Could be the key lock tumbler, but most likely the anti theft system thinks a theft attempt was made. I need info on reseting the anti theft sys. and a diagnostic proceedure as the GM service manuel does not cover this area.

  • wmason54 May 30, 2009

    Alright guys..listen up... I found the gremlin hidding under the dash.

    Turns out the previous owner had a passlock,( bypass? still not too sure what it is), installed. When I installed the replacement vcm and did the relearn procedure, the "module" would have had to be reset to the new signal voltage. This missmatch in signals made the" module" interupt the start signal from the ignition switch and groug the horn circuit,( making the horn sound, like the van was being stolen!). Since I have no idea who what this module is or how to reprogram it, simply removing it from the wiring harness was the only option, and it worked!!!!!

  • Anonymous Mar 15, 2014

    i cant relearn my new fob cause I can't switch the "remote relearning active" mode!!!!! it just skiped to "remote key relearn"

  • Anonymous Mar 20, 2014

    which gm relearn procedure would i use after replacing the ignition lock cylinder?

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Have the computer re-flashed

Posted on May 29, 2009

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Posted on Jan 02, 2017

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How to program key to ignition for a 1998 Chevy truck w/vortex v6 engine..I tried it myself an it did crank but will not stay running


Program KEY ? There is no transponder in the key for a 1998 Chevy truck . What problem are you have ,no start ? Is the SECRUITY light lit on the dash ? you don't need to program keys with this ant-theft system .
Vehicle Theft Deterrent (VTD) Operation
The design of the passlock system is to prevent the vehicle operation if the proper ignition key is not used in order to start the vehicle. The mechanical key, in normal operation, will turn the passlock lock cylinder. The passlock sensor will relay the passlock data to theEVO/Passlock module. The EVO/Passlock module will determine the validity of the passlock data. The EVO/Passlock module will send a code password to the vehicle/powertrain control module (VCM/PCM). When the VCM/PCM receives the correct code the VCM/PCM allows the fuel injectors to operate normally. The passlock system requires the VCM and the EVO/Passlock module to communicate the various functions in order to operate. These functions transmit over the class 2 serial data line CKT 1807. For an explanation of the class 2 serial data operation refer to Data Link Communications Circuit Description in Wiring Systems.
Passlock System
The design of the passlock system is to prevent vehicle theft by disabling the engine unless the passlock lock cylinder rotates properly by engaging the correct ignition key. The system is similar in concept to the passkey system. However, the passlock eliminates the need for a key mounted resistor pellet. The components of the system are as follows:
?€¢
The ignition lock cylinder


?€¢
The ignition switch


?€¢
The passlock sensor


?€¢
The EVO/Passlock module


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The security indicator


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The vehicle/powertrain control module (VCM/PCM)

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I PUT A DIFFERENT ENGINE COMPUTER IN MY 1999 GMC SAVANNA VAN 1500 SERIES. CHANGED OUT MONDALE. IT STILL WILL NOT EVEN APEMP TO START.


Important:
?€¢
Service of the vehicle control module (VCM) consists of either replacement of the VCM or reprogramming of the VCM.


?€¢
If the VCM is being replaced, the knock sensor (KS) module must be transferred to the replacement VCM.


?€¢
The replacement VCM must be programmed before the vehicle will run.


?€¢
The replacement VCM must have the Passlock Reprogramming procedure performed before the vehicle will run.


?€¢
The replacement VCM must have the CKP System Variation Learn procedure performed or a DTC P1336 will set

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How to reset security ignition on a 1999 chevy silverado?


There is a lot of info on this site that you can read up on. http://vatspasslockpasskeysecurityhelp.yolasite.com/

Sep 07, 2014 | 1999 Chevrolet Silverado 1500

1 Answer

Someone tried to steal my 2000 Chevy s10. I replaced the ignition cylinder which came with two keys. I tried to do the 30 minute relearn but the security light doesn't stay on long enough to do the...


For the anti-theft system in your S-10 , no key relearn is needed . No chip (transponder) in the key ! Has a sensor that is part of the lock cylinder housing , and a magnet that is part of the lock cylinder ! When you turn the key the magnet passes the sensor creating a signal that is sent to the BCM - body control module ! The BCM will send a password to the vehicle/powertrain control module (VCM/PCM). When the VCM/PCM receives the correct password the VCM/PCM allows the fuel injectors to operate normally. The passlock™ system requires the VCM/PCM and the BCM to communicate the various functions in order to operate. These functions transmit over the class 2 serial data line CKT 1807. For an explanation of the class 2 serial data operation refer to Data Link Communications Circuit Description in Data Link .
Is the security light lit ?
Conditions
Use this procedure after replacing:
• Passlock™ Sensor
• BCM
• VCM
• PCM

10 Minute Re-Learn Procedure
Tools Required
• Tech 2
• Techline terminal with current SPS (Service Programming System) software
Connect the Tech 2 to the vehicle.
Select "Request Information" under "Service Programming".
Disconnect the Tech 2 from the vehicle and connect it to a techline terminal.
On the techline terminal, select "Theft Module Re-Learn" under "Service Programming".
Disconnect the Tech 2 from the techline terminal and connect it to the vehicle.
Turn ON the ignition, with the engine OFF.
Select "VTD Re-Learn" under "Service Programming".
Attempt to start the engine, then release the key to ON (vehicle will not start).
Observe the SECURITY telltale, after approximately 10 minutes the telltale will turn OFF (the vehicle is now ready to relearn the Passlock™ Sensor Data Code and/or password on the next ignition switch transition from OFF to CRANK).
Turn OFF the ignition, and wait 5 seconds.
Start the engine (the vehicle has now learned the password).
With the Tech 2 (scan tool), clear any DTCs.

your best bet , take it to a GM dealer

May 28, 2017 | Cars & Trucks

2 Answers

Someone tried to steal my 2000 Chevy S10 pickup. They tore up ignition. I purchased a new ignition cylinder which came with 2 keys. I tried to do the 30 minute relearn but the security light does not stay...


You don't need to program key's with this anti-theft system , there is no chip inside . Did you get a correct lock cylinder. . On this system there is a pass lock sensor in side an the lock clinder has a magnet !
Passlock™ Sensor
The passlock™ sensor is inside the upper right side of the steering column. The passlock™ sensor contains 2 hall effect sensors. The tamper hall effect sensor is on the top. The security hall effect sensor is under the tamper hall effect sensor. Both of the hall effect sensors monitor the magnet of the lock cylinder through an opening. The tamper hall effect sensor is physically placed on top of the security hall effect sensor. This arrangement enables the tamper hall effect sensor to engage first if an intruder attempts to bypass the passlock™ sensor by placing a large magnet around that area of the steering column. There is a tamper resistor inside the passlock™ sensor in order to help prevent tamper to the system. Passlock™ equipped vehicles have a selection of 10 different security resistors ranging from 0.5K ohms up to 13.6K ohms. Installing one of the security resistors inside the passlock™ sensor will generate a unique passlock™ code. All 10 combinations of the passlock™ sensor have the same part number. However, you cannot simply replace the passlock™ sensor and expect the system to operate properly. Always start by performing the Diagnostic System Check first and following the instructions.
Body Control Module
The Body Control Module (BCM) contains the theft deterrent system logic. The BCM reads the passlock™ data from the passlock™ sensor. If the passlock™ data is correct, the BCM will pass theft. The BCM will then transmit the code password to the VCM/PCM.
During the tamper mode the vehicle may start. The vehicle will then stall. If the BCM receives the wrong passlock™ data, the VTD will immediately go into the tamper mode. The tamper mode will lock-out the vehicle fuel injectors for 10 minutes. The SECURITY indicator will flash while the VTD is in the tamper mode.
If the passlock™ sensor sends a correct password to the BCM when the ignition is in the ON position, the BCM will send a fuel enable signal to the VCM/PCM. The VCM/PCM will not disable the fuel due to any BCM message for the remainder of the ignition cycle.

You only need to do a relearn if one of these are replaced
Use this procedure after replacing:
• Passlock™ Sensor
• BCM
• VCM
• PCM

Did you replace any of these ?

30 Minute Re-Learn Procedure
Turn ON the ignition, with the engine OFF.
Attempt to start the engine, then release the key to ON (vehicle will not start).
Observe the SECURITY telltale, after approximately 10 minutes the telltale will turn OFF.
Turn OFF the ignition, and wait 5 seconds.
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 Passlock™ 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.
Start the engine (the vehicle has now learned the Passlock™ Sensor Data Code and/or password).
With a scan tool, clear any DTCs if desired (history DTCs will self clear after 100 ignition cycles).

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1 Answer

Anti-thief system cut off power to den gine an won't cut it back on


If you are dealing with the anti theft the anti theft will flash as you are trying to start the vehicle if this is the case then it is the anti theft if not then you are not dealing with a ant theft issue. You can do a 30 minute relearn procedure without a scan tool. here is how Turn ignition on without the engine reunning.attempt to start the vehicle then release the key to ON.(vehicle doest start) Observe the security light.afeter 10 minutes the security light will turn off.Turn off the ignition and wait 5 seconds.do this 3 times for 30 minutes. start the engine with the engine started the vehicle will learn the passlock key.

Feb 24, 2012 | Cars & Trucks

1 Answer

Anti theft on after replacing computer in my 1998 cadillad devill


That is the procedure for passlock 2 but you have to do that procedure 3 times in a row. Does you key have a PK3 stamped on it?

Apr 01, 2010 | 1998 Cadillac DeVille

2 Answers

Can i get a new ignition switch for my 1999 LS will the sensors be affected?


Yes you can install and new ignition switch in your Blazer, once you have installed the new switch, your going to have to do a PASSLOCK II relearn for the new ignition key's to start the Blazer.
PASSLOCK - Reprogramming Auto Learn

IMPORTANT:

* The Body Control Module (BCM) must be programmed with the proper RPO configurations before performing learn procedures. See BCM Programming/RPO Configuration.
* If replacing the BCM with a GM Service Parts Operations (SPO) replacement part, the module will learn PASSLOCK sensor data code immediately. The existing VCM/PCM however, must learn the new fuel continue password when the BCM is replaced.
* If replacing a VCM/PCM with a GM Service Parts Operations (SPO) replacement part, after programming, these modules will learn the incoming fuel continue password immediately upon receipt of a password message. Once a password message is received, and a password is learned, a learn procedure must be performed to change this password again. A VCM/PCM which has been previously installed in another vehicle will have learned the other vehicle's fuel continue password and will require a learn procedure after programming to learn the current vehicle's password.

CONDITIONS
Use this procedure after replacing:

* Passlock Sensor
* BCM
* VCM
* PCM

30 MINUTE RE-LEARN PROCEDURE

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. Observe 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 PASSLOCK 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 desired (history DTCs will self clear after 100 ignition cycles).

Thank you foe using Fixya

Mar 20, 2010 | 1999 Chevrolet Blazer

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