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John, Master A.S.E Automotive technician
Category: Chevy
Satisfied Customers: 9176
Experience:  A.S.E MasterTechnician A1-A8 w/L1,38 years experience General Motors Master Technician
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2000 chev impala, 3.4 liter. Security light comes on when ...

Resolved Question:

2000 chev impala, 3.4 liter. Security light comes on when driving, sometimes stays on other times not. It woulod not let me start one time and I messed with the "settings" menu through the radio and got it started. Can you clarify what settings menu is actually controling the security light in this situation? light is still coming on sometimes. Thanx, Rod.
Submitted: 6 years ago.
Category: Chevy
Expert:  John replied 6 years ago.

HelloCustomer

When checking for codes for the vehicle theft deterrent system you must enter the BCM(body control module) , the IPC(instrument panel cluster) & the PCM(powertrain control module) communication circuit & see if any failures are present or history.These onboard computers communicate with each other & establish a safeguard for the vehicle.Sometimes there are intermitten failures that are not recorded & are very hard yo find.When working with this system I suggest using a Tech2 with the latest software ypdate from GM.This will help in incorrect data from an aftermarket tool.I am sending some information to help you understand the system.

 

Document ID# XXXXX
2000 Chevrolet Impala

 

Content Theft Deterrent (CTD) Operation

Refer to Vehicle Personalization/Customization for procedures on enabling or disabling the content theft deterrent (CTD) system.

Arming

Complete the following steps in order to arm the content theft deterrent (CTD) system:

  1. Turn the ignition switch to the OFF position.
  2. Remove the key from the ignition lock cylinder.
  3. Open the driver's door.
  4. Press the lock on either power door lock switch or the keyless entry transmitter.

The security indicator lamp flashes while the driver door is open during the arming cycle. The lamp lights steadily when the following conditions exist:

The driver side door is closed.
The content theft deterrent system enters the arming mode.

The lamp flashes continuously at a slow rate when the content theft deterrent system is armed. Refer to Vehicle Personalization/Customization for procedures on enabling or disabling the LOCK switch arming feature.

Disarming

Use either of the following steps in order to disarm the content theft deterrent system:

Unlock either door by using the key in the key lock cylinder.
Press UNLOCK on a keyless entry transmitter.

Refer to Vehicle Personalization/Customization for procedures on enabling or disabling the lock cylinder disarming feature.

Alarm

The CTD activates the alarm when the system is armed and one of the following events occurs:

A door is opened.
The ignition switch is turned to one of the following positions:
- ACC
- RUN
- ON
The rear compartment lock cylinder is removed from the rear compartment lid.
The ALARM button is pressed on the keyless entry transmitter.

Important: The following actions occur when the transmitter ALARM button is pressed:

The interior lamps light.
The horn sounds intermittently.
The headlamps flash for 2 minutes.
These actions will end when one of the following actions occurs:
The ALARM button is pressed again.
The ignition key is turned to the RUN or the ON position.

 

The CTD causes the following signals for 2 minutes during alarm mode:

The headlamps flash.
The horn is sounded.
Operating Modes

The content theft deterrent system has the following operating modes:

The stand-by mode
The lamp flashing mode
The lamp steady ON mode
The ignition ON mode
The delay mode
The armed mode
The re-arm wait mode
The warning mode
The alarm mode
The trunk wait mode
The trunk open mode
The trunk delay mode
Stand-By Mode

The cluster security lamp is OFF during the stand-by mode.

The content theft deterrent system enters the stand-by mode when all of the following conditions exist:

The doors are unlocked in one of the following ways:
- UNLOCK is pressed on the keyless entry transmitter.
- The door key cylinders are used when the arm/disarm is in mode 1.
The ignition switch is in the OFF or UNLOCK position with the key fully inserted in the ignition key lock cylinder.
All of the vehicle doors are closed.

Turning the ignition switch to the ACC or the RUN position causes the content theft deterrent system to exit the stand-by mode and enter into the ignition ON mode.

Lamp Flashing Mode

In the lamp flashing mode, the lamp flashes for 10 minutes and then turns OFF. In vehicles with less than 15 total accumulated miles, the lamp flashes for 3 minutes.

The content theft deterrent system enters the lamp flashing mode when all of the following conditions exist:

The key is removed from the ignition key lock cylinder.
Any door is open.
The doors are unlocked in one of the following ways:
- UNLOCK is pressed on the keyless entry transmitter.
- The door key cylinders are used when the arm/disarm is in mode 1.

The content theft deterrent system exits the lamp flashing mode and goes into the ignition ON mode when the ignition switch is turned to the ACC or the RUN position.

Lamp On Steady Mode

In the Lamp On Steady mode, the lamp is ON for 10 minutes and then turns OFF. In vehicles with less than 15 total accumulated miles, the lamp turns ON for 3 minutes.

The content theft deterrent system enters the Lamp On Steady mode when all of the following conditions exist:

The ignition switch is removed from the ignition key lock cylinder.
Any door is open.
LOCK is pressed on the keyless entry transmitter or the power door lock switch.

The content theft deterrent system exits the Lamp On Steady mode and goes into the Ignition On Mode when the ignition switch is turned to the ACC or RUN position.

Ignition On Mode

In the Ignition On Mode, the lamp is in the OFF position.

Turning the ignition switch to the ACC or RUN position during one of the following modes will cause the theft deterrent system to enter into the ignition mode:

Stand-by
Lamp flashing
Lamp ON steady
Delayed
Delay Mode

In the delay mode, the lamp is ON.

The content theft deterrent system enters the delay mode when all of the following conditions exist:

The key is removed from the ignition key lock cylinder.
All of the doors are closed.
The rear compartment lid is closed.
LOCK is pressed on the keyless entry transmitter or a power door lock switch.

The BCM remains in delay mode for 1 second and then goes into armed mode. If the rear compartment lid is open, the BCM goes into the trunk open mode.

The content theft deterrent system exits the delay mode and goes into the Ignition On Mode when the ignition switch is turned to the ACC or RUN position.

Armed Mode

In the armed mode, the lamp flashes slowly.

When the content theft deterrent system enters the armed mode, the BCM performs the following functions:

For remote activation verification in mode 3 or mode 4, the BCM sounds the horn for 23-27 ms.
For remote activation verification in mode 2, mode 3 or mode 4, the BCM flashes the headlamps once after sounding the horn.

The content theft deterrent system stays in the armed mode until one of the following conditions exists:

LOCK is pressed on the keyless entry transmitter. The system goes into the stand-by mode.
The door is unlocked using the door key cylinder when the arm/disarm is in mode 1 or mode 3. The system goes into the stand-by mode.
A vehicle door is opened. The system goes into the alarm mode.
Tampering with the rear compartment lock occurs. The system goes into the warning mode.
The ignition switch is turned from the OFF position to the ACC or RUN position. The system goes into the alarm mode.
The rear compartment lid is opened. The system goes into the trunk open mode.
Re-Arm Wait Mode

In the re-arm wait mode, the lamp is ON. The BCM waits for all trigger inputs to clear before entering the re-arm wait mode after an alarm mode operation. The content theft deterrent system stays in the re-arm wait mode for 2 seconds when all of the following conditions exist:

All of the vehicle doors remain closed.
No tampering occurs with the rear compartment lock.
The ignition switch remains in the OFF position.

After 2 seconds, the content theft deterrent system goes into the armed mode. If the rear compartment lid is open, the content theft deterrent system goes into the trunk open mode.

Alarm Mode

In the alarm mode, the lamp is ON.

The BCM flashes the headlamps and sounds the horn alternately for 2 minutes. The content theft deterrent system then enters the re-arm wait mode.

The content theft deterrent system stays in the alarm mode until one of the following actions occurs:

LOCK is pressed on the keyless entry transmitter. The system goes into the stand-by mode.
The door is unlocked using the door key cylinder when the arm/disarm is in mode 1 or mode 3. The system goes into the stand-by mode.
ALARM is pressed on the keyless entry transmitter. The system goes into the re-arm wait mode.
Trunk Wait Mode

In the trunk wait mode, the lamp flashes. The content theft deterrent system enters the trunk wait mode the REAR COMPARTMENT button on the keyless entry transmitter is pressed. The BCM monitors the trunk open input in order to receive a signal indicating that the rear compartment lid is open.

The content theft deterrent system stays in the trunk wait mode until one of the following actions occurs:

The rear compartment lid is opened. The system goes into the trunk open mode.
UNLOCK is pressed on the keyless entry transmitter. The system goes into the stand-by mode.
The door is unlocked using the door key cylinder when the arm/disarm is in mode 1 or mode 3. The system goes into the stand-by mode.
A vehicle door is opened. The system goes into the alarm mode.
The ignition switch is turned from the OFF position to the ACC or RUN position. The system goes into the alarm mode.
Trunk Open Mode

In the trunk open mode, the lamp flashes. The BCM enters the re-arm wait mode when the rear compartment closes. When the content theft deterrent system is in the trunk open mode, the BCM ignores inputs from the shock sensor and the rear compartment lid tamper switch.

The BCM causes the following actions when the CTD enters the trunk open mode:

For remote activation verification in mode 3 or mode 4, the BCM sounds the horn once.
For remote activation verification in mode 2, mode 3 or mode 4, the BCM flashes the headlamps once.

The content theft deterrent system stays in the trunk open mode until one of the following actions occurs:

The rear compartment lid is closed. The system goes into the trunk delay mode.
UNLOCK is pressed on the keyless entry transmitter. The system goes into the stand-by mode.
The door is unlocked using the door key cylinder when the arm/disarm is in mode 1 or mode 3. The system goes into the stand-by mode.
A vehicle door is opened. The system goes into the alarm mode.
Turning the ignition switch from the OFF position to the ACC or RUN position causes the system to go into the alarm mode.
Trunk Delay Mode

In the trunk delay mode, the lamp flashes. After the rear compartment is closed, the content theft deterrent system waits 2 seconds before going into the re-arm wait mode. When the content theft deterrent system is in the trunk delay mode.

The CTD system stays in the trunk delay mode for 2 seconds, or until one of the following actions occurs:

UNLOCK is pressed on the keyless entry transmitter. The system goes into the stand-by mode.
The door is unlocked using the door key cylinder when the arm/disarm is in mode 1 or mode 3. The system goes into the stand-by mode.
A vehicle door is opened. The system goes into the alarm mode.
The ignition switch is turned from the OFF position to the ACC or RUN position. The system goes into the alarm mode.
The rear compartment lid is opened. The system goes into the trunk open mode.

After 2 seconds in the trunk delay mode, the CTD system goes into the re-arm wait mode.


Document ID# XXXXX
2000 Chevrolet Impala

 

Document ID# XXXXX
2000 Chevrolet Impala

 

Vehicle Theft Deterrent (VTD)Circuit Description

Circuit Description

The Passlock theft deterrent system contains a Passlock sensor that is part of the ignition lock cylinder assembly. The body control module (BCM) provides voltage (B+) to the Passlock sensor through the Passlock sensor power circuit when the ignition switch is in the ACCESSORY, ON, or START position. The BCM also provides a 5-volt reference to the Passlock data circuit. The BCM provides ground to the Passlock sensor through the Passlock sensor ground circuit. The Passlock sensor interfaces with the BCM through the Passlock sensor data circuit.

When you turn the ignition switch to the START position with the proper key, the Passlock sensor applies a unique resistance value to the Passlock Data Circuit which pulls the 5-volt reference down to a unique voltage value, which is measured by the BCM. This analog voltage signal is unique and varies from vehicle to vehicle. When you attempt to start the engine, the BCM compares a previously stored (learned) voltage value with the circuit voltage value:

  • When the values match, the BCM sends a fuel enable password XXXXX the Class 2 serial data link to the powertrain control module (PCM). The PCM then enables the crank relay, and allows fuel delivery to the engine.
  • When the values do not match, the BCM sends a fuel disable password XXXXX the Class 2 serial data link to the powertrain control module (PCM). As a result, the PCM disables the crank relay, and does not allow fuel delivery to the engine.

Document ID# XXXXX
2000 Chevrolet Impala

 

John, Master A.S.E Automotive technician
Category: Chevy
Satisfied Customers: 9176
Experience: A.S.E MasterTechnician A1-A8 w/L1,38 years experience General Motors Master Technician
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