Circuit Description
The theft deterrent module (TDM) sends the fuel enable password to the powertrain control module (PCM) via the serial data circuit. The PCM verifies the fuel enable password received matches the password stored in memory. If the fuel enable password is correct, the PCM enables the starting and fuel delivery systems. When replacing a PCM with a GM SPO replacement part, the new PCM will learn the incoming fuel continue password immediately upon receipt. DTC P1630 is an informational code indicating the PCM is ready to learn the fuel continue password.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC P1630 Theft Deterrent Learn Mode Active
Conditions for Running the DTC
The ignition switch is in the ACCESSORY or RUN position.
Conditions for Setting the DTC
The PCM remains in theft deterrent password learn mode for more than 2 seconds.
Actions Taken When the DTC Sets
| • | The PCM sends a serial data message to the body control module (BCM) to illuminate the SECURITY indicator. |
| • | The PCM will not illuminate the malfunction indicator lamp (MIL). |
Conditions for Clearing the MIL/DTC
| • | A history DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction. |
| • | The DTC can be cleared by using a scan tool. |
Diagnostic Aids
A GM SPO replacement PCM is in a functional state to learn the password from the theft deterrent module. If the TDM is replaced, the PCM must be placed in password learning mode to relearn the new password. Once learned, the password becomes permanent information that remains in the PCM. The loss of PCM battery or ignition voltage does not affect the programmed password information. Refer to Programming Theft Deterrent System Components .
Step | Action | Yes | No |
|---|---|---|---|
Schematic Reference: Theft Deterrent System Schematics | |||
1 | Did you perform the Diagnostic System Check - Vehicle? | ||
