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 |

1. Turn the ignition switch to OFF.
2. Disconnect the deterrent module connector.
3. Turn the ignition switch to ON.
4. Measure the voltage from the theft deterrent module harness connector terminal A3 to ground.

Does the voltage approximately equal the specified value?

5 Volts

Go to Step 6

Go to Step 3

3 | Inspect the PCM connector C1 terminal 53 (Oldsmobile) or Terminal 70 (Buick) for proper terminal contact. Refer to Intermittents and Poor Connections Diagnosis in Wiring Systems. Is the connector OK? | -- | Go to Step 5 | Go to Step 4
4 | Repair the terminal contact. Refer to Repairing Connector Terminals in Wiring Systems. Did you complete the repair? | -- | Go to Vehicle Theft Deterrent (VTD) System Check | --
5 | Test CKT 229 for an open or short to ground. Is the circuit OK? | -- | Go to

• | Engine Cranks but Does Not Run in Engine Controls-3.8L

• | Engine Cranks but Does Not Run in Engine Controls-4.0L,4.6L

Go to Step 9

6 |

1. Turn the ignition switch to OFF.
2. Reconnect the theft deterrent module connector.
3. Turn the ignition switch to ON.
4. Backprobe the theft deterrent module.
5. Measure the voltage from the theft deterrent module terminal A3 to ground.

Does the voltage approximately equal the specified value?

2.5 Volts

Go to Vehicle Theft Deterrent (VTD) System Check

Go to Step 7

7 | Inspect the theft deterrent module connector terminal A3 for proper terminal contact. Refer to Intermittents and Poor Connections Diagnosis in Wiring Systems. Is the terminal contact OK? | -- | Go to Step 8 | Go to Step 4
8 | Replace the theft deterrent module. Refer to Theft Deterrent Module Replacement Did you complete the repair? | -- | Go to Vehicle Theft Deterrent (VTD) System Check | --
9 | Repair the open or short to ground in CKT 229. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Vehicle Theft Deterrent (VTD) System Check | --