GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2005 🢒 Envoy - 4WD 🢒 Accessories 🢒 Theft Deterrent 🢒 DTC P1630

Circuit Description

This diagnostic test checks for the enable password learning flag indicating the powertrain control module (PCM) is in learn password mode. This mode allows the PCM to learn the password from the Passlock™ module at assembly or when being serviced. The password needs to be learned whenever the PCM or the Passlock™ module is replaced.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC P1630 Theft Deterrent Learn Mode Active

Conditions for Running the DTC

The ignition is in the ON position.

Conditions for Setting the DTC

When the enable learning flag is set.

Action Taken When the DTC Sets

The malfunction indicator lamp (MIL) will not illuminate.

Conditions for Clearing the MIL/DTC
    • A history DTC clears after 40 consecutive warm-up cycles, if this or any other emission related diagnostic does not report any failures.
    • The scan tool Clear Info function was used.

Diagnostic Aids

The PCM in learn mode is a DTC for the vehicle at the assembly plant, dealership, and outside garage personnel as an indication that the learn mode is enabled. This means the PCM is now ready to learn a new password.

Test Description

The number below refers to the step number on the diagnostic table.

  1. If any of the listed DTCs are set, the PCM will not receive and learn a valid password.

Step

Action

Yes

No

Schematic Reference: Theft Deterrent System Schematics

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle in Vehicle DTC Information

2
  1. Install a scan tool.
  2. Momentarily rotate the ignition switch to CRANK. Do not start the vehicle.
  3. Release the ignition switch to ON.
  4. Select the powertrain control module (PCM) display DTCs function on the scan tool.

Does the scan tool display DTC P1630 as a current DTC?

Go to Step 3

Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems

3

Does the scan tool display DTC B2945, B2955, P1626, or P1631?

Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC Information

Go to Step 5

4

Replace the PCM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming.

Did you complete the replacement?

Go to Step 5

--

5
  1. Use the scan tool in order to clear any DTCs.
  2. Turn OFF the ignition.
  3. Start the vehicle.
  4. Select the PCM display DTCs function on the scan tool.

Does DTC P1630 reset?

Go to Step 3

System OK