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goodwrench9124, ASE Certified Technician
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2003 saturn vue: security system, vehical..light comes..locking..doors

Resolved Question:

2003 saturn vue, having trouble with security system, vehical has a problem with the system, car will not always start, when the car does start it will run normal, butat times when car is started the security light comes on and the fuel pump will not turn on. (i know this is what it supposed to do). the remote works at locking and unlocking the doors (batteries have been just changed). aanother problem is that the dealer will not check out the system, because the vehical is registered to my daughter, who is currently outside the u.s., she left the vehical with my wife to use in her absence, my wife has had to stop using the vehical, because it has malfuncion leaving her stranded, at nite , my wife is in her 60s and comes from work after dark, on a old two lane mountain road. is there anyway to disarm the security system in an emergency so that she can move the vehical.
Submitted: 9 years ago.
Category: Chevy
Expert:  goodwrench9124 replied 9 years ago.

Hello and welcome to JA!!!, there are many things that can cause this security light to come and cause a no start. the only real way to properly diag this system is with a class two scan tool. normally done at the dealer. not sure why the dealer wont work on??? I have included how the system works and how complex it is. I have also included a relearn process that you can do yourself. this might get you out of a pinch and may correct concern. but more than likely it will need to be checked out by a dealer..


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 PasslockTM Sensor Data Code and/or passwords on the next ignition switch transition from OFF to CRANK.

    Important: The vehicle learns the PasslockTM Sensor Data Code and/or password XXXXX 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 PasslockTM 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.

Vehicle Theft Deterrent (VTD) Description and Operation

PasslockTM System

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 PasslockTM 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 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 PasslockTM 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 PASS-Key® system. However, the PasslockTM system eliminates the need for a key mounted resistor pellet. The components of the PasslockTM system are as follows:

The ignition lock cylinder
The ignition switch
The PasslockTM sensor
The Body control module (BCM)
The security telltale
The vehicle/powertrain control module (VCM/PCM)

Ignition Lock Cylinder and Housing

The ignition lock cylinder is located at the upper right side of the steering column. The PasslockTM sensor is in the steering column. The PasslockTM 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 XXXXX 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 XXXXX order to enable the fuel injectors.
The vehicle will not start.

Ignition Switch

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.

PasslockTM Sensor

The PasslockTM sensor is inside the ignition cylinder lock housing. The PasslockTM 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 PasslockTM sensor by placing a large magnet around that area of the steering column. There is a tamper resistor inside the PasslockTM sensor in order to help prevent tamper to the system. PasslockTM 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 PasslockTM sensor will generate a unique PasslockTM code. All 10 combinations of the PasslockTM sensor have the same part number. However, you cannot simply replace the PasslockTM 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 PasslockTM data from the PasslockTM sensor. If the PasslockTM data is correct, the BCM will pass theft. The BCM will then transmit the fuel continue password XXXXX the VCM/PCM.

During the tamper mode the vehicle may start. The vehicle will then stall. If the BCM receives the wrong PasslockTM 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 PasslockTM sensor sends a correct password XXXXX 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.


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.

Vehicle/Powertrain Control Module

The VCM/PCM communicates with the BCM over the Class 2 serial data line. When the BCM determines a no start condition, it sends a Class 2 serial data password XXXXX the VCM/PCM in order to disable the fuel injection system. If the BCM receives the expected voltage from the PasslockTM sensor, the BCM sends a class 2 serial data password XXXXX the VCM/PCM in order to enable the fuel injection system. The VCM/PCM then allows the vehicle to start correctly. If the Class 2 serial data password XXXXX the BCM to the VCM/PCM is not within the Vehicle Security Status Message, the fuel injectors will shut OFF during a start attempt. The SECURITY telltale will be illuminated for 10 minutes. If the VCM/PCM does not receive the same password XXXXX the BCM as the last learned one, the vehicle will start and then stalls due to the Fuel Lockout.

Fuel Lockout Cycle

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

Changing the PasslockTM Components

The design of the PasslockTM 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 PasslockTM sensor

If you replace any of these parts the vehicle may start and stall 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 telltale will be flashing for the full 10 minutes and the DTC B3031 will be set. The BCM and the VCM/PCM require the full 10 minutes in order to complete a learn cycle. The ignition switch must remain in the RUN position until the SECURITY telltale stops flashing. You will need to repeat the cycle if the ignition switch does not remain in the RUN position. When replacing any of the above parts it is recommended to perform the Programming Theft Deterrent System Components procedure.

The design of the PasslockTM 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 PasslockTM sensor monitoring the position of the lock cylinder will relay the PasslockTM data to the body control module (BCM). The BCM will determine the validity of the PasslockTM data. The BCM will send a fuel continue password XXXXX the vehicle/powertrain control module (VCM/PCM). When the VCM/PCM receives the correct password XXXXX VCM/PCM allows the fuel injectors to operate normally. The PasslockTM 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. For an explanation of the class 2 serial data description and operation, refer to Data Link Communications Description and Operation in Data Link Communications.


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