P1631

DTC P1631

CIRCUIT DESCRIPTION
This test inspects for mismatched passwords between the powertrain interface module (PIM) and powertrain control module (PCM). Whenever replacing the PIM or PCM, follow the Theft Learn procedure for the system to learn the new password. This is a type C DTC.

CONDITIONS FOR RUNNING THE DTC
The ignition is on and the PCM is waiting for the correct password.

CONDITIONS FOR SETTING THE DTC
The PCM detects an incorrect password from the PIM.

ACTION TAKEN WHEN THE DTC SETS
- The PCM stores the DTC information into memory when the diagnostic runs and fails.
- The Check Powertrain malfunction indicator lamp (MIL) will not be activated.
- The PCM records the operating conditions at the time the diagnostic fails.
- The PCM stores this information in the Failure Records.
- The engine cranks but may not start.
- The multifunction display (MFD) in the Instrument panel, will display a message at key-on and key-off.

CONDITIONS FOR CLEARING THE MIL/DTC
- A Last Test Failed (current DTC) clears when the diagnostic runs and passes.
- A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic.
- Use Tech 2 to clear the DTC.

DIAGNOSTIC AIDS
Remove any debris from the PCM module connector surfaces before servicing the PCM module.

The PCM in learn mode is a DTC for the personnel at the assembly plant, retailer, or outside garage as an indication that the system enables the learn mode. This means the PCM is now ready to learn a new password from the PIM while in the learn mode. When this occurs, the vehicle is vulnerable to vehicle theft. If using Tech 2 and TIS for password linking, refer to Body Control Module (BCM) Programming/RPO Configuration in Body Control System for the linking procedure. This Tech 2 operation will take approximately 2 minutes to perform. If no Tech 2 and TIS is available, the following DTC P1631 diagnostic table must be followed.

TEST DESCRIPTION

Step 1 - 4:

The numbers below refer to the step numbers on the diagnostic table.
2. The time criteria is a minimum required amount of time. The time limit can exceed this limit without interfering with the Auto Learn Procedure.
4. If DTC P1631 is set, this indicates that you did not follow the procedure correctly. Perform the Re-learn procedure again.