For 1990-2009 cars

Step | Action | Value(s) | 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 | Try to start the engine. Does the engine crank? | -- | Go to Step 5 | Go to Step 3
3 | Inspect the following theft deterrent module connector terminals for proper connections. Refer to Intermittents and Poor Connections Diagnosis in Wiring Systems.

• | Terminal A1

• | Terminal A2

• | Terminal B2

• | Terminal B5

• | Terminal B6

Are the contacts OK?

--

Go to Step 4

Go to Step 15

4 |

• | Test the following power and ground circuits to the theft deterrent module for an open:

- | CKT 439 (Oldsmobile)

- | CKT 1020 (Buick)

- | CKT 851

- | CKT 1642

• | Check the following power circuits for a short to ground:

- | CKT 439 (Oldsmobile)

- | CKT 1020 (Buick)

- | CKT 1642

Are the circuits OK?

--

Go to Step 10

Go to Step 14

5 |

1. Turn the ignition switch to OFF.
2. Disconnect the theft deterrent module connector.
3. Turn the ignition switch to ON
4. Measure the voltage from the theft deterrent module connector terminal A5 to ground.

Does the voltage measure within the specified range?

10-15 V

Go to Step 7

Go to Step 6

6 | Observe one of the following indicators:

• | Instrument cluster (Buick)

• | Remote indicator bank (Oldsmobile)

Do the indicators turn on?

--

Go to Step 11

Go to Instrument Cluster System Check in Instrument Panel, Gauges and Console

7 | Connect a fused jumper from the theft deterrent module harness connector terminal A5 to ground. Does the security indicator turn on? | -- | Go to Step 9 | Go to Step 8
8 | Repair the short to battery in CKT 264. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | Go to Vehicle Theft Deterrent (VTD) System Check | --
9 | Inspect the theft deterrent module connector terminal A5 for proper connection. Refer to Intermittents and Poor Connections Diagnosis in Wiring Systems. Is the contact OK? | -- | Go to Step 10 | --
10 | Replace the theft deterrent module. Refer to Theft Deterrent Module Replacement Is the repair complete? | -- | Go to Vehicle Theft Deterrent (VTD) System Check | --
11 | Inspect the Instrument Panel fuse. Is the fuse OK? | -- | Go to Step 12 | --
12 |

• | Test CKT 40 for a short to ground.

• | Test CKT 264 and CKT 40 for an open.

Are the circuits OK?

--

Go to Step 13

Go to Step 14

13 |

• | Inspect the indicator bulb.

• | Inspect one of the following connectors for proper connection. Refer to Intermittents and Poor Connections Diagnosis in Wiring Systems.

• | Instrument cluster (Buick)

• | Remote indicator bank (Oldsmobile)

Are the connectors OK?

--

Go to Vehicle Theft Deterrent (VTD) System Check

--

14 | Repair the suspect circuit. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | Go to Vehicle Theft Deterrent (VTD) System Check | --
15 | Repair the terminal contact. Refer to Repairing Connector Terminals in Wiring Systems. Is the repair complete? | -- | Go to Vehicle Theft Deterrent (VTD) System Check | --