SECURITY Indicator Always On or Flashing. Buick LeSabre 1999

For 1990-2009 cars only

Makes 🢒 Buick 🢒 1999 🢒 LeSabre 🢒 Engine 🢒 Engine Electrical 🢒 SECURITY Indicator Always On or Flashing

SECURITY Indicator Always On or Flashing Engine Starts

Step	Action	Yes	No
1	Did you perform the Vehicle Theft Deterrent (VTD) System Check?	Go to Step 2	Go to Vehicle Theft Deterrent (VTD) System Check
2	Perform a lock cylinder and key test usingJ 35628-A Interrogator. Did the test pass?	Go to Step 3	Go to Step 8
3	Turn the ignition switch to OFF. Disconnect the Theft Deterrent Module Connector. Turn the ignition switch to RUN. Does the SECURITY indicator turn OFF?	Go to Theft Deterrent Module Replacement	Go to Step 4
4	Is the vehicle equipped with content theft deterrent (UA6)?	Go to Step 5	Go to Step 6
5	Disconnect the remote function actuator (RFA) module connector. Does the SECURITY indicator turn OFF?	Go to Step 7	Go to Step 6
6	Repair short to ground in CKT 264. Refer to Wiring Repairs in Wiring Systems. Is the repair complete?	Go to Vehicle Theft Deterrent (VTD) System Check	--
7	Replace the RFA module. Refer to Remote Control Door Lock Receiver Replacement . Is the replacement complete?	Go to Vehicle Theft Deterrent (VTD) System Check	--
8	Repair short to ground or open in circuits 1073 or 1074. Refer to Wiring Repairs in Wiring Systems. Did you find and correct the condition?	System OK	Go to Ignition Lock Cylinder Replacement - On Vehicle

SECURITY Indicator Always On or Flashing Engine Does Not Crank

Step

Action

Value(s)

Yes

Did you perform the Vehicle Theft Deterrent (VTD) System Check?

Go to Step 2

Go to Vehicle Theft Deterrent (VTD) System Check

Test the key in the J 35628-A J Interrogator.

Is the key code valid?

Go to Step 4

Go to Step 3

Clean the key.
Retest the key in the J 35628-A Interrogator.

Is the key code valid?

Go to Content Theft Deterrent (CTD) System Check

Go to Step 17

Connect both of the J 35628-90 Adaptor Harness 48-way connectors to C202.
Connect both J 35628-90 2-way connector to the J 35628-A Interrogator.
Test the lock cylinder with the following procedure:

3.1.	With the proper key, rotate the ignition lock cylinder through all positions.

3.2.	While rotating, observe the key code display for any variance in key code number.

3.3.	Repeat the procedure multiple times to verify any intermittent concerns.

Does the display change to another key code value or E at any position?

Go to Step 6

Go to Step 5

Turn the ignition switch to OFF.
Disconnect the J 35628-90 Adaptor Harness and the J 35628-A Interrogator.
Measure the resistance from connector C202 (ignition lock side) terminal E13 to ground.

Is the resistance within the specified range?

Go to Step 19

Go to Step 6

Replace the ignition lock cylinder and keys. Refer to Ignition Lock Cylinder Replacement - On Vehicle

Is the repair complete?

Go to Content Theft Deterrent (CTD) System Check

Reconnect connector C202.
Measure the resistance across the key pellet. Record the value.
Put the key into the ignition lock cylinder.
Disconnect the theft deterrent module connector.
Measure the resistance from the theft deterrent module harness connector terminal B7 to terminal B8.

Does the resistance measure within the specified range of the key pellet resistance?

0-10 ohms

Go to Step 10

Go to Step 8

Inspect connector C202 terminal E12 and terminal E13 for proper connections.

Refer to Intermittents and Poor Connections Diagnosis in Wiring Systems.

Are the connections OK?

Go to Step 9

Go to Step 20

Repair either of the following circuits for an open or high resistance between connector C202 and the theft deterrent module connector:

•	CKT 1073 (WHT/BLK)

•	CKT 1074 (PPL/WHT). Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

Go to Content Theft Deterrent (CTD) System Check

Place the key in the ignition lock cylinder in the OFF position.
Measure the resistance from the theft deterrent module harness connector terminal B8 to ground.

Is the resistance less than or equal to the specified value?

Go to Step 11

Go to Step 21

Repair a short to ground in CKT 1073 (WHT/BLK) between connector C202 at the base of the steering column and the theft deterrent module connector. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

Go to Content Theft Deterrent (CTD) System Check

Inspect the ground to the theft deterrent module harness connector for proper connections.

Refer to Intermittents and Poor Connections Diagnosis in Wiring Systems.

Are the terminal contacts OK?

Go to Step 13

Go to Step 23

Reconnect the theft deterrent module connector.
Try to start the engine.

Does the engine start?

Go to Step 15

Go to Step 14

Turn the ignition switch to ON.
Observe the security indicator.

Does the indicator turn off after 3 minutes?

Go to Step 16

Go to Step 18

Inspect connector C202 for proper connection.

Refer to Intermittents and Poor Connections Diagnosis in Wiring Systems.

Is the terminal contact OK?

Go to Step 24

Go to Step 20

Try to start the engine with a spare key.

Does the engine start?

Go to Step 17

Go to Step 18

Replace the suspect key.
Match the key code with the spare key.

Is the replacement complete?

Go to Content Theft Deterrent (CTD) System Check

Replace the theft deterrent module. Refer to Theft Deterrent Module Replacement

Is the replacement complete?

Go to Content Theft Deterrent (CTD) System Check

Turn the ignition OFF.
Measure the resistance from connector C202 (ignition lock side) terminal E12 to ground.

Is the resistance within the specified range?

Go to Step 7

Go to Step 6

Repair poor terminal contact. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

Go to Content Theft Deterrent (CTD) System Check

Turn the ignition OFF.
Measure the resistance from the theft deterrent module harness connector terminal B7 to ground.

Is the resistance less than or equal to the specified range?

Go to Step 12

Go to Step 22

Repair a short to ground in CKT 1074 (PPL/WHT) between connector C202 at the base of the steering column and the theft deterrent module. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

Go to Content Theft Deterrent (CTD) System Check

Repair the ground to the theft deterrent module. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

Go to Content Theft Deterrent (CTD) System Check

Inspect the theft deterrent module connectors for proper contact.

Refer to Intermittents and Poor Connections Diagnosis in Wiring Systems.

Is the terminal contact OK?

Go to Content Theft Deterrent (CTD) System Check

Go to Step 20