Ignition switch not working properly sometimes it starts and other times won't. passlock icon occasionally comes on and stays on. do i need a sensor or can it be bypassed

Just making sure that you did a proper relearn:

30 Minute 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.
ImportantThe 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.

You might also check the 10A TBC fuse under the hood.
If the relearn procedure works, but you continue to have security immobilizer issues, you will probably need to replace the halo sensor. You can get a kit from GM.

It is the passlock system not safelock An you can't just disable it . It is software program into the BCM - body control module an the PCM - powertrain control module .Simply disconnecting the wires from the ignition to the BCM will render your vehicle useless . If an when the security symbol light is on you need to have it checked for DTC'S - diagnostic trouble codes . A GM dealer ,Chevy , Buick , Cadillac etc.... we know Pontiac is no longer around. Everything will work except the PCM will not let the fuel injectors work .
Passlock?"¢ System
The theft deterrent system has been incorporated into the body control module (BCM). The theft deterrent system is provided in order to prevent the vehicle operation if the correct key is not used in order to start the vehicle. The ignition key allows the lock cylinder to rotate. The cylinder rotation produces an analog voltage code in the Passlock?"¢ sensor. This voltage code is received by the BCM. The BCM compares the voltage code to the previously learned voltage code. If the codes match, a serial data message is sent from the BCM to the powertrain control module (PCM). The message enables the fuel injector operation.
The design of the Passlock?"¢ system is to prevent vehicle theft by disabling the engine unless the ignition lock cylinder rotates properly by engaging the correct ignition key. The system is similar in concept to the Passkey system. However, the Passlock?"¢ system eliminates the need for any key mounted components. The components of the Passlock?"¢ system are as follows:
?€¢
The ignition lock cylinder

?€¢
The ignition switch

?€¢
The Passlock?"¢ sensor

?€¢
The BCM

?€¢
The security indicator

?€¢
The PCM

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

?€¢
The security indicator

?€¢
The vehicle/powertrain control module (VCM/PCM)

need to reprogram the security system. turn the key to start position then to run . let the key stay on until the light stops flashing. repeat these steps 3 times then the car should start if there is not a problem with the pass-lock sensor in the ignition switch or the BCM( body control module).

Read the following paragraph from GM, this will give you some insight on the passlock system on your vehicle.

The electrical switching portion of the ignition lock cylinder assembly is separate from the key and lock cylinder. The electrical switch portion and the key and lock cylinder synchronize and work in conjunction through the action of the mechanical assembly between the two components.

PASSLOCK(TM) SENSOR
The Passlock(TM) 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(TM) sensor by placing a large magnet around that area of the steering column. There is a tamper resistor inside the Passlock(TM) sensor in order to help prevent tamper to the system. Passlock(TM) 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(TM) sensor will generate a unique Passlock(TM) code. All 10 combinations of the Passlock(TM) sensor have the same part number.

BODY CONTROL MODULE
The body control module (BCM) contains the theft deterrent system logic. The BCM reads the Passlock(TM) data from the Passlock(TM) sensor. If the Passlock(TM) data is correct, the BCM will send a class 2 message to the PCM to enable the fuel injectors and crank relay.

During the tamper mode the vehicle may start. The vehicle will then stall. If the BCM receives the wrong Passlock(TM) data, the VTD system will immediately go into the tamper mode. The tamper mode will lock-out the vehicle fuel injectors and crank relay for 10 minutes . The SECURITY indicator will flash while the VTD is in the tamper mode.

If the Passlock(TM) sensor sends a correct password to the BCM when the ignition is in the ON position, the BCM will send a fuel enable and crank relay enable signal to the PCM.

SECURITY INDICATOR
The SECURITY indicator appears on the message center inside the instrument cluster. If the SECURITY indicator flashes or if the SECURITY indicator lights continuously during vehicle operation, refer to the system diagnosis.

POWERTRAIN CONTROL MODULE
The PCM communicates with the BCM over the Class 2 serial data line. When the BCM determines an incorrect password, it sends a Class 2 serial data password to the PCM in order to disable the crank relay and fuel injection system. If the BCM receives the expected voltage from the Passlock(TM) sensor, the BCM sends a class 2 serial data password to the PCM in order to enable the crank relay and fuel injection system. The PCM then allows the vehicle to start normally.

FUEL LOCKOUT CYCLE
The Passlock(TM) system has a lockout cycle of approximately 10 minutes . Once the vehicle is in the lockout cycle, the vehicle remains in the lockout cycle for 10 minutes , even if the ignition switch is turned from the ON position to the OFF position.

The Passlock(TM) system uses the lockout cycle in order to synchronize all of the Passlock(TM) components when any Passlock(TM) related part is replaced. The Passlock(TM) system requires 3 consecutive lockout cycles in order to complete the 30 minute learn procedure for a changed component.

CHANGING THE PASSLOCK(TM) COMPONENTS
The design of the Passlock(TM) system is to prevent theft even if the various theft deterrent parts change. The parts that can no longer be changed without the possibility of going into a tamper mode are:

* The Passlock(TM) sensor
* The BCM
* The PCM

If you replace any of these parts the vehicle may not start for 10 minutes . This is the long tamper mode. If this occurs, the system must go through a long tamper mode cycle. During this time the SECURITY indicator will be flashing for the full 10 minutes and DTC B3031 will be set. The BCM and the PCM require the full 10 minutes in order to complete a learn cycle. The ignition switch must remain in the ON position until the SECURITY indicator stops flashing. You will need to repeat the cycle if the ignition switch does not remain in the ON position. When replacing any of the above parts, perform the Programming Theft Deterrent System Components procedure.

The design of the Passlock(TM) 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 ignition lock cylinder. The Passlock(TM) sensor monitoring the position of the lock cylinder will relay the Passlock(TM) data to the body control module (BCM). The BCM will determine the validity of the Passlock(TM) data. The BCM will send a password to the powertrain control module (PCM). When the PCM receives the correct password the PCM allows the crank relay and fuel injectors to operate normally. The Passlock(TM) system requires the PCM and the BCM to communicate the various functions in order to operate. These functions transmit over the class 2 serial data line. For an explanation of the class 2 serial data description and operation refer to Data Link Communications Description and Operation in Data Link Communications.

Your Passlock may need to relearn the ignition keys, if the ignition lock has gone bad like my in-laws Grand Am Gt, here is what i did so they will not get stranded any more. Buy a Passlock by pass module for around $70.00. You can order one from GMPASSLOCK.COM in the mean time try resetting the Passlock. Good luck

Ignition keys relearn takes about 30 min to do. 30-Minute Learn Procedure
1.) Turn ON the ignition, with the engine OFF.
2.) Attempt to start the engine, then release the key to ON; the vehicle will not start.
3.) Observe the SECURITY tell tale light. After approximately 10 minutes, the light will turn OFF.
4.) Turn OFF the ignition switch, and wait 5 seconds.
5.) Repeat steps 1 through 4 - two more times - for a total of 3 cycles of 10 minutes. 3x10 = 30 minutes.
The vehicle is now ready to relearn the Passlock Sensor Data Code and/or passwords on the next ignition switch turn from OFF to CRANK Important: Turn the Ignition Switch OFF. 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 needed. History DTCs will self clear after 100 ignition cycles.

Without a scan tool you may have momentary starter interruptions while history clears itself. Keep me posted, be glad to know you got your car running 100% again soon.

You could have a start that has gone bad and will need to be replace,or your having a Passlock system problem.

Your Passlock may need to relearn the ignition keys, if the ignition lock has gone bad like my in-laws Grand Am Gt, here is what i did so they will not get stranded any more. Buy a Passlock by pass module for around $70.00. You can orderone from GMPASSLOCK.COM in the mean time try resetting the Passlock. Good luck

Ignition keys relearn takes about 30 min to do. 30-Minute Learn Procedure
1.) Turn ON the ignition, with the engine OFF.
2.) Attempt to start the engine, then release the key to ON; the vehicle will not start.
3.) Observe the SECURITY tell tale light. After approximately 10 minutes, the light will turn OFF.
4.) Turn OFF the ignition switch, and wait 5 seconds.
5.) Repeat steps 1 through 4 - two more times - for a total of 3 cycles of 10 minutes. 3x10 = 30 minutes.
The vehicle is now ready to relearn the Passlock Sensor Data Code and/or passwords on the next ignition switch turn from OFF to CRANK Important: Turn the Ignition Switch OFF. 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 needed. History DTCs will self clear after 100 ignition cycles.

Without a scan tool you may have momentary starter interruptions while history clears itself.

Here is the procedure to resetting your Passlock immobilize

• 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 needed, history DTCs will self clear after 100 ignition cycles

Common for the ignition lock switch it self has gone bad and will need to be replaced. This is more common if you have lots of keys on your your key chain, the extra weigh wear out the electrical sleeves in the cylinder walls making the passlock not to read the proper resistor reading on your ignition keys and needs to be reset all the time. My In-Laws had the same problem with there Grans Am and was at the deal once a year for it. Once the warranty ended I got the passlock 2 by pass for around $70.00. The factor alarm still works but the ignition immobilize was disabled so they would not get stranded out in the cold. Here is the link and good luck, keep me posted and it's just a plug and play so there is not wire cutting and splicing. Keep me posted and don't forget the rate. http://www.gmpasslock.com/

If you tried to hot wire the ignition, you may have shorted out the pass lock wire in the ignition switch. You may have to replace the ignition switch. Try the relearn process, it takes about 30 min to do. 30-Minute Learn Procedure 1. Turn ON the ignition, with the engine OFF. 2. Attempt to start the engine, then release the key to ON; the vehicle will not start. 3. Observe the SECURITY tell tale light. After approximately 10 minutes, the light will turn OFF. 4. Turn OFF the ignition switch, and wait 5 seconds. 5. Repeat steps 1 through 4 - two more times - for a total of 3 cycles of 10 minutes. 3x10 = 30 minutes. The vehicle is now ready to relearn the Passlock Sensor Data Code and/or passwords on the next ignition switch turn from OFF to CRANK. Important: Turn the Ignition Switch OFF. 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 needed. History DTCs will self clear after 100 ignition cycles. Without a scan tool you may have momentary starter interruptions while history clears itself. Good luck and hope this helps. Keep me posted, be glad to help.

Sounds like it is the ignition switch. You need to purchase a new switch from the dealer and make sure that it is a redesigned one, or at least get their guarantee that the new one will not fail.

There is most likely a build up of grease inside the switch. This is a design flaw with the factory switches, but has apparently been fixed with new switches from the dealer. Like I said, just make sure it is a new one when you are buying it from the dealer. You will need to perform a Passlock Relearn once the new switch is installed.

The old ignition switch will need to be replaced. If you feel like saving yourself some money and do it yourself the follow the instructions below.

1. Remove cover behind the steering wheel
2. Unplug the switch and unscrew the two torx bolts
3. Install new switch by reversing process.

Any time a component in the Passlock system is changed, the learn procedure must be completed for the Theft Deterrent System to sync the password. The procedure requires no special tech tools or computers.

30 Minute 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 light, after approximately 10 minutes the telltale light will turn OFF.
4. 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.

You should be good to go. Good Luck!