Will having pcm reflashed solve the passlock security problem 98 S10

How do you know it's the security system ? Light lit on the insturment cluster ? If it is there are DTC'S - diagnostic trouble codes stored in the BCM - body control module . There are no tricks , have codes checked do the diagnostics for that code , fix the problem an it will start .
The vehicle theft deterrent (VTD) functions are provided by the Passlock system. Passlock consists of the following components:
• A standard ignition key
• An ignition lock cylinder assembly, including a Passlock sensor
• The body control module (BCM)
• The powertrain control module (PCM).
The Passlock sensor contains a magnet on the lock cylinder and a hall effect switch on the surrounding assembly. When you rotate this cylinder using an ignition key with the proper mechanical cut, the magnet on the lock cylinder activates the hall effect switch. When activated, the Passlock sensor provides a unique resistance value to the Passlock data circuit of the BCM. The resulting voltage is measured by the BCM. This voltage value is compared to one stored in memory (a learned value). If the Passlock data voltage value matches the learned value, the BCM sends a password, via the class 2 serial data link, to the PCM. The PCM compares this value to one stored in memory (a learned password). If the passwords match, the PCM enables engine starting.

DTC B2947 Security System Sensor Power CKT Low
DTC B2948 Security System Sensor Power CKT High
DTC B2957 Security System Sensor Data Circuit Low
DTC B2958 Security System Sensor Data Circuit High
DTC B2960 Sec Sys Sensor Data Incorrect but Valid
DTC B3031 Security System Controller in Learn Mode
DTC B3033 Security System Indicates Tamper

Do yourself a favor , take it to a qualified repair shop .

What's wrong with it , have you had it checked for DTC'S - diagnostice trouble codes .

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 the body control module (BCM). The BCM will determine the validity of the passlock™ data. The BCM 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/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 Connector Circuit Description in Wiring Systems.

Telltale Indication
Condition
ON constant for 3 seconds, then OFF
The bulb check occurs upon power-up (Ignition 1 and crank).
ON constant for 3 seconds, OFF momentarily, ON constant/ignition OFF
DTC (current) is set with the ignition ON (see DTC B2947, B2948, B2957 and B2958).
ON constant/ignition OFF
The TBC fuse is open or an open in CKT 1140
ON constant for 3 seconds, FLASH for 10 minutes, then OFF
Occurs when a Passlock™ sensor has been replaced and the ignition switch has been turned from the OFF position to the CRANK position. This sequence occurs 3 times.
FLASH with the ignition ON
The Passlock system is in a tamper mode (see DTC B2960 and B3033).
ON constant for 3 seconds, OFF momentarily, then ON constant for 10 minutes, then OFF
Occurs when a new BCM or a new PCM/VCM has been installed, and the ignition switch has been turned from the OFF position to the CRANK position. This sequence occurs 3 times.
ON constant for 3 seconds, OFF for 2 seconds, then ON constant
The IPC is unable to communicate with the BCM.


DTC B2947 Security System Sensor Power CKT Low
DTC B2948 Security System Sensor Power CKT High
DTC B2957 Security System Sensor Data Circuit Low
DTC B2958 Security System Sensor Data Circuit High
DTC B2960 Sec Sys Sensor Data Incorrect but Valid
DTC B3031 Security System Controller in Learn Mode
DTC B3033 Security System Indicates Tamper .

Your best bet , take your vehicle to a qualified repair shop .

No you didn't ! you only think you did . Turn signal switch has nothing to do with it .
Ignition Lock Cylinder and Housing
The ignition lock cylinder is located at the upper right side of the steering column. The Passlock™ sensor is in the steering column. The Passlock™ sensor is separate from the key and lock cylinder. The key and the lock cylinder work together in order to determine if the proper ignition key was used to start the vehicle.
In the event of an open Class 2 serial data line between the BCM and the VCM/PCM, the vehicle will become fail-enabled if the VCM/PCM has already received the password from the BCM for that ignition cycle (the engine is running). In this event, the following conditions occur:
• The security telltale will be ON continuously.
• The VCM/PCM will become fail-enabled for future ignition cycles.
If a failure in the Class 2 serial data line occurs before the ignition cycle, when the VCM/PCM is not fail-enabled, the following conditions occur:
• The VCM/PCM will never receive a valid password in order to enable the fuel injectors.
• The vehicle will not start.

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 the body control module (BCM). The BCM will determine the validity of the passlock™ data. The BCM 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/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 Connector Circuit Description in Wiring Systems.
Your best bet , take it to a qualified repair shop , there is a real possibility of rendering your vehicle useless if you don't know what your doing

Passlock
The passlock system is a vehicle theft deterrent system which deters drive-away vehicle theft by disabling engine operation if the ignition lock cylinder is not rotated with the proper mechanically cut key.
The passlock system is made up of an ignition switch assembly, passlock sensor, body control module (BCM), instrument panel cluster (IPC), and a powertrain control module (PCM).
The ignition switch contains a magnet mounted on the lock cylinder and a passlock sensor assembly which consists of security hall effect sensor, tamper hall effect sensor, and output resistors. A drill proof metal shield is also staked over the sensor housing.
The passlock sensor mounted to the ignition switch assembly is located inside the upper right side of the steering column. The passlock sensor contains two hall effect sensors: a tamper hall effect sensor and a security hall effect sensor. The tamper hall effect sensor is mounted on top of the security hall effect sensor. Should someone attempt to defeat the system by use of magnetic experimentation, the tamper hall effect sensor will activate first.
The BCM has the passlock controller integrated into it which controls the majority of the security systems logic. The BCM reads the data from the passlock sensor continuously. If the data is correct and has been received by the BCM within a specified time, the BCM will send a coded password to the PCM. The PCM will then allow the fuel injectors to operate.
The coded password for the security system is sent from the body control module to the PCM via the class 2 data link. If the password is correct and received within the specified time, the PCM will allow the fuel injectors to operate.
The IPC contains the security telltale. The security telltale has three modes of operation, OFF, FLASHING, and ON.
SECURITY TELLTALE will be off if:
?€¢
Ignition is in the OFF position

?€¢
Ignition is in the RUN, START, or ACC position and security system diagnostics have all PASSED

SECURITY TELLTALE will be on if:
?€¢
The BCM is performing a bulb check at vehicle start

?€¢
Security system diagnostics have not yet completed at vehicle start

?€¢
A security system diagnostic trouble code (DTC) is set in the BCM or PCM

SECURITY TELLTALE will be flashing if:
?€¢
The tamper hall effect sensor has been triggered

?€¢
Incorrect passlock sensor data to BCM for more than 5 seconds during vehicle start

?€¢
No passlock sensor data to the BCM for more than 5 seconds during vehicle start

?€¢
Incorrect password from the BCM to the PCM after 5 seconds during vehicle start

No ,the box is probably not bad , but you need to have it programmed . The dealer is the only one that can do that ? The keys don't matter .
The passlock sensor mounted to the ignition switch assembly is located inside the upper right side of the steering column. The passlock sensor contains two hall effect sensors: a tamper hall effect sensor and a security hall effect sensor. The tamper hall effect sensor is mounted on top of the security hall effect sensor. Should someone attempt to defeat the system by use of magnetic experimentation, the tamper hall effect sensor will activate first.
The passlock system is a vehicle theft deterrent system which deters drive-away vehicle theft by disabling engine operation if the ignition lock cylinder is not rotated with the proper mechanically cut key.
The passlock system is made up of an ignition switch assembly, passlock sensor, body control module (BCM), instrument panel cluster (IPC), and a powertrain control module (PCM).
The ignition switch contains a magnet mounted on the lock cylinder and a passlock sensor assembly which consists of security hall effect sensor, tamper hall effect sensor, and output resistors. A drill proof metal shield is also staked over the sensor housing.
The passlock sensor mounted to the ignition switch assembly is located inside the upper right side of the steering column. The passlock sensor contains two hall effect sensors: a tamper hall effect sensor and a security hall effect sensor. The tamper hall effect sensor is mounted on top of the security hall effect sensor. Should someone attempt to defeat the system by use of magnetic experimentation, the tamper hall effect sensor will activate first.
The BCM has the passlock controller integrated into it which controls the majority of the security systems logic. The BCM reads the data from the passlock sensor continuously. If the data is correct and has been received by the BCM within a specified time, the BCM will send a coded password to the PCM. The PCM will then allow the fuel injectors to operate.
The coded password for the security system is sent from the body control module to the PCM via the class 2 data link. If the password is correct and received within the specified time, the PCM will allow the fuel injectors to operate.
Sorry but you can't just replace parts , you need to know how the system works . You need to take this to a ASE certified repair facility that knows how it works .

There is a problem with the system an there is a DTC - diagnostic trouble code stored in the body control module !
The vehicle theft deterrent system is designed in order to prevent vehicle theft by disabling the fuel injectors unless the lock cylinder is engaged by the correct mechanical key. The theft deterrent system uses the following 4 components for theft prevention:
?€¢
The lock cylinder

?€¢
The ignition switch

?€¢
The body control module (BCM)

?€¢
The powertrain control module (PCM)

When starting the engine, the PCM searches for a password from the BCM through the Class 2 serial data circuit. If the password is not recognized or not present, the PCM will disable the fuel injectors. Two modes of tamper detection are provided:
?€¢
No password received

The engine will start and stall quickly. SECURITY telltale will flash on the instrument panel cluster (IPC) and then stay ON steady.

?€¢
Incorrect or disable password received (More than 3 invalid passwords are received)

The engine is disabled for at least 10 minutes and the SECURITY telltale will illuminate solid on the IPC during the 10 minutes.

After the vehicle has passed theft detection, the PCM will continue normal operation
Ignition Switch
The mechanical key and lock cylinder is located on the steering column. The main electrical switching portion of the assembly is separate from the key and lock cylinder. The VTD portion of the ignition switch is the Passlock?"¢ cylinder.
The Passlock?"¢ lock cylinder is a locking cylinder that turns a magnet past a stationary hall effect sensor. When turned to crank, the hall effect sensor is latched which applies a fixed resistance to the Passlock?"¢ signal data circuit. The voltage measured by the BCM on the Passlock?"¢ signal data circuit is the Passlock?"¢ data value.
Body Control Module (BCM)
The BCM compares the Passlock?"¢ data value to a value that it has stored in memory. If the values match the BCM sends a password via the class 2 serial data line to the PCM.
Powertrain Control Module (PCM)
When the PCM receives the correct password, the PCM enables the fuel injection system, allowing the vehicle to operate correctly. The PCM may allow the car to start and quickly stall during a failed theft condition.
If the BCM does not receive a Passlock?"¢ data value, the BCM will enter a short tamper mode. During this mode, the VTD system will not allow the car to operate for 4 seconds.
If the Passlock?"¢ data value is incorrect, the VTD system will enter the long tamper mode. In the long tamper mode, the following actions will occur:
?€¢
The THEFT SYSTEM indicator will flash.

?€¢
The fuel injectors will be shut off for approximately 10 minutes.

Although the vehicle may start, the engine will quickly stall due to a fuel cut-off.
In the event of an open in the serial data communication between the BCM and the PCM or a failure in the Passlock?"¢ lock cylinder, the following actions occur:
?€¢
The VTD system will become fail-enabled if the car has already passed theft for that ignition cycle (i.e. the engine is running).

?€¢
The PCM or the BCM may set diagnostic trouble codes (DTCs).

?€¢
The THEFT SYSTEM indicator will light continuously.

?€¢
The PCM will become fail-enabled for future ignition cycles.

If a failure occurs when the ignition is off, while the VTD system is not fail-enabled, the PCM will never receive a valid password, and will not allow vehicle operation by disabling the fuel injectors. An this system can set 6 DTC'S
DTC B2947 Security System Sensor Power CKT Low DTC B2948 Security System Sensor Power CKT High DTC B2957 Security System Sensor Data Circuit Low DTC B2958 Security System Sensor Data Circuit High DTC B2960 Sec Sys Sensor Data Incorrect but Valid DTC B3031 Security System Controller in Learn Mode DTC B3033 Security System Indicates Tamper

Do you have a security light lit or flashing on the Instrument cluster ?
The theft deterrent system has been incorporated into the body control module (BCM). The theft deterrent 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 turns the lock cylinder. 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 previousely learned voltage code. If the codes match, a class 2 message is sent from the BCM to the powertrain control module (PCM)/vehicle control module (VCM). The message enables the fuel injectors.
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 a key mounted resistor pellet. The components of the passlock?"¢ system are as follows:
?€¢
The ignition lock cylinder

?€¢
The ignition switch

?€¢
The passlock?"¢ sensor

?€¢
The Body control module (BCM)

?€¢
The security telltale

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

The ignition lock cylinder is located at the upper right side of the steering column. The Passlock?"¢ sensor is in the steering column. The Passlock?"¢ sensor is separate from the key and lock cylinder. The key and the lock cylinder work together in order to determine if the proper ignition key was used to start the vehicle.
In the event of an open Class 2 serial data line between the BCM and the VCM/PCM, the vehicle will become fail-enabled if the VCM/PCM has already received the password from the BCM for that ignition cycle (the engine is running). In this event, the following conditions occur:
?€¢
The security telltale will be ON continuously.

?€¢
The VCM/PCM will become fail-enabled for future ignition cycles.

If a failure in the Class 2 serial data line occurs before the ignition cycle, when the VCM/PCM is not fail-enabled, the following conditions occur:
?€¢
The VCM/PCM will never receive a valid password in order to enable the fuel injectors.

?€¢
The vehicle will not start.

The lock cylinder and the visible key insert portion of the ignition switch are located at the upper right side of the steering column. The electrical switching portion of the assembly is separate from the key and lock cylinder. The electrical switch portion is hidden inside the steering column. The electrical switch portion and the key and lock cylinder synchronize and work in conjunction through the action of the mechanical assembly between the 2 parts.
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.
SECURITY Telltale
The SECURITY telltale appears on the message center inside the instrument cluster. If the SECURITY telltale flashes or if the SECURITY telltale lights continuously during the vehicle operation, refer to the system diagnosis.
Fuel Lockout Cycle
The Passlock?"¢ 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 RUN position to the OFF position.
The Passlock?"¢ system uses the lockout cycle in order to synchronize all of the Passlock?"¢ components when any Passlock?"¢ related part is changed. The Passlock?"¢ system requires 3 consecutive lockout cycles in order to complete the 30 minute learn procedure for a changed component.

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).

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.

Are you sure this is your problem? I don't believe passlock connects to the pcm. It usually goes thru the bcm to disable the start relay.