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 serviced. The password needs to be learned whenever the PCM or the passlock module is replaced, or an ignition key that has an improper resistance.
Conditions for Running the DTC
The PCM is ready to learn a new password from the passlock module.
Conditions for Setting the DTC
The passlock module is not sending a valid password or not sending a password at all.
Action Taken When the DTC Sets
| • | The engine starts and stalls when the passlock module detects a theft mode. |
| • | The engine starts and stalls when the PCM losses communication with the passlock module. |
| • | The engine operates normally, but an internal passlock module failure has occurred. |
| • | The PCM stores the DTC information into memory when the diagnostic runs and fails. |
| • | The malfunction indicator lamp (MIL) will not illuminate. |
| • | The PCM records the operating conditions at the time the diagnostic fails. The PCM stores this information in the Failure Records. |
Conditions for Clearing the DTC
| • | A History DTC will clear after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic. |
| • | A last test failed, or current DTC, will clear when the diagnostic runs and does not fail. |
| • | Use a scan tool in order to clear the DTC. |
Diagnostic Aids
Important: Remove any debris from the PCM module connector surfaces before servicing the PCM module. Inspect the PCM module connector gaskets when diagnosing or replacing the modules. Ensure that the gaskets are installed correctly. The gaskets prevent contaminate intrusion into the PCM modules.
The PCM in learn mode is a DTC for the vehicle at the assembly plant, dealership, and the outside garage personnel as an indication that the system enables the learn mode. This means the PCM is now ready to learn a new password from the passlock module. This DTC set because the passlock module never sent a valid password to the PCM while in learn mode. When this occurs, the vehicle is vulnerable to vehicle theft.
Step | Action | Values | Yes | No |
|---|---|---|---|---|
1 | Did you perform the Powertrain On-Board Diagnostic (OBD) System Check? | -- | Go to Passlock Module Diagnosis |
