Vehicle Theft Deterrent (VTD) Operation. Chevrolet Lumina 1998

For 1990-2009 cars only

Makes 🢒 Chevrolet 🢒 1998 🢒 Lumina 🢒 Body and Accessories 🢒 Theft Deterrent 🢒 Vehicle Theft Deterrent (VTD) Operation

Ignition Key With Correct Resistor Pellet Code is Used To Start Engine

The theft deterrent module performs the following actions when the correct ignition key is used in order to start the vehicle:

•	Enables the theft deterrent relay. The theft deterrent relay enables the starter unit.

•	Sends a password to the Powertrain Control Module (PCM) through the fuel enable signal circuit. As a result, the PCM allows fuel delivery to the engine.

Ignition Key With Wrong Resistor Pellet Code is Used To Start Engine

The theft deterrent module performs one of the two following actions when you attempt to start the vehicle with a wrong ignition key:

•

There are 15 PASS-Key® II resistance ranges. The PASS-Key® II resistance may be one of the 14 valid but incorrect PASS-Key® II resistance ranges. The theft deterrent module will perform the following actions when you attempt to start the vehicle (if the condition is present during an engine start attempt or for 1 second any time after the engine has started):

•	Turns on the SECURITY indicator

•	Sends a password to the PCM through the fuel enable signal circuit

•	The password disables fuel delivery to the engine.

•	Disables the theft deterrent relay, which disables the starter circuit

•	Disables sampling of the PASS-Key® II resistance for 3 minutes

•	The 3 minute time period is called the shut-down period.

•	Disconnecting the battery will not clear the timer sequence. The timer sequence will resume when battery power is restored.

•	Inserting the proper key during the vehicle shut-down period will not start the engine. The engine will not start until the shut-down period has elapsed.

•	After the shut-down period, the engine will start if the correct ignition key resistor pellet is used.

•	The PASS-Key® II resistance may be correct and allow the engine to start. Later during the same ignition cycle, the PASS-Key® II resistance may be one of the 14 valid but incorrect resistance ranges. The theft deterrent module will perform the following actions:

•	Enters the fail-enable mode

•	Turns ON the SECURITY indicator

•	Sends a password to the PCM through the fuel enable signal circuit when more attempts to start the engine occur

•	The password allows the fuel enable circuit to deliver fuel to the engine.

•	Enables the theft deterrent relay, which also enables the starter circuit.

Key Detection Circuit Malfunctions

Key detection circuit malfunctions include the following conditions:

•

An open

•	A short to voltage

•	A short to ground

The theft deterrent module turns ON the SECURITY indicator when a key detection circuit malfunction occurs.

If the malfunction is present when you attempt to start the engine, the theft deterrent module performs the following actions:

•	Sends a password to the PCM through the fuel enable signal circuit

This password disables fuel delivery to the engine.

•	Disables the theft deterrent relay

The vehicle will exhibit a no-crank engine condition.

If the malfunction is present after the engine is started, the theft deterrent module enters a fail-enable mode. The theft deterrent module performs the following actions when you attempt to start the engine again:

•	Sends a password to the PCM through the fuel enable circuit

This password enables fuel delivery to the engine.

•	Enables the theft deterrent relay

The engine will start.

Unprogrammed Theft Deterrent Module (Non-SEO Vehicles)

If you replace a theft deterrent mode, program it to accept the resistance value of the existing vehicle keys in order to allow correct operation of PASS-Key® II.

A new service replacement theft deterrent module is programmed to store the first resistor pellet code it detects.

When the theft deterrent module is unable to detect a valid PASS-Key® II resistor pellet code, the programming sequence never ends. During the programming sequence, the theft deterrent module performs the following actions:

•	Flashes the SECURITY indicator.

•	Enables the theft deterrent relay, which enables the starter circuit.

•	Sends a password to the PCM through the fuel enable signal circuit

The password enables fuel delivery to the engine.

•	The engine starts.

•	The programming sequence ends when the theft deterrent module is able to detect a valid PASS-Key® II resistor pellet code.

The engine starts. The programming sequence ends when the theft deterrent module is able to detect a valid PASS-Key® II resistor pellet code.

Unprogrammed Theft Deterrent Module (SEO Equipped Vehicles)

If you replace a theft deterrent module on an SEO equipped vehicle, do not program the theft deterrent module.

The key detection circuit wires on non-SEO equipped vehicles are shorted together. This prevents unnecessary theft deterrent module programming. Refer to Theft Deterrent System Schematics .

When the theft deterrent module is left unprogrammed, the theft deterrent module will never end the programming sequence. During the programming sequence, the theft deterrent module performs the following actions:

•	Sends an output (ground) to the Data Link Connector (DLC) terminal 8.

•	Enables the theft deterrent relay. This also enables the starter circuit.

•	Sends a password to the PCM through the fuel enable signal circuit in order to enable fuel delivery to the engine.

•	The engine starts.

If by any chance the theft deterrent module programs itself, the vehicle will experience a no-crank condition. This may be caused by an open or excessive resistance in the key detection circuit jumper wire. Refer to Theft Deterrent System Schematics .