DTC P1631 Theft Deterrent Start Enable Signal Not Correct. Cadillac Concours 1996

For 1990-2009 cars

### Circuit Description

This test checks for mismatched passwords between the IPC and PCM. Whenever the IPC or PCM are replaced, a theft learn procedure must be followed in order for the new password to be learned.

### Conditions for Setting the DTC

#### Test Condition

Vehicle Anti-Theft system enabled.

#### Failure Conditions

• | Fuel disable lockout set.

• | An incorrect fuel continue password has been received.

### Action Taken When the DTC Sets

• | The Malfunction Indicator Lamp (MIL) will not illuminate.

• | No message will be displayed.

### Conditions for Clearing the DTC

• | A History DTC will clear after forty consecutive warm-up cycles with no failures of any non-emission related diagnostic test.

• | A Last Test Failed (current) DTC will clear when the diagnostic runs and does not fail.

• | Use a scan tool to clear DTCs.

• | Interrupting PCM battery voltage may or may not clear DTCs. This practice is not recommended. Refer to Clearing Diagnostic Trouble Codes in PCM Description and Operation.

Step | Action | Value(s) | Yes | No
--- | --- | --- | --- | ---
1 | Was the Powertrain On-Board Diagnostic (OBD) System Check performed? | -- | Refer to Theft Learn Procedure | Go to A Powertrain On Board Diagnostic (OBD) System Check