Circuit Description
This diagnostic test checks for the Enable Password Learning Flag indicating that the powertrain control module (PCM) is in learn password mode. This mode allows the PCM to learn the password from the powertrain interface module (PIM) at assembly or when serviced. The password needs to be learned whenever the PCM, or the PIM is replaced. This is a type C DTC.
Conditions for Running the DTC
The PCM is in the learn password mode.
Conditions for Setting the DTC
The PCM is ready to learn a new password from the PIM, but the PIM is not sending a valid password or not sending a password at all.
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 will display a message at key-on and key-off. |
Conditions for Clearing the MIL/DTC
| • | The 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
The PCM in learn mode is a DTC for servicing personnel, as an indication that the system has enabled the learn mode. This means the PCM is now ready to learn a new password from the PIM.
This DTC set because the PIM never sent a valid password to the PCM while in learn mode. When this occurs, the vehicle is vulnerable to vehicle theft. Also, if there is a problem with the UART serial data line between the body control module and PIM, this may cause this condition.
Inspect the BCM for DTCs that may apply to the UART circuit. If any are found, refer to these DTCs first. If both PCM DTCs P1626, and P1630 are set, check PIM power feed and ground circuits for opens or shorts. If a problem was found with PIM ground circuit, repair ground circuit, then power down PCM (key OFF) for 30 seconds. Key ON and retest.
Test Description
The numbers below refer to the step numbers on the diagnostic table.
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If both PCM DTCs P1626, and P1630 are set, check for a fault with either the PIM power feed or PIM ground circuits.
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If a PIM, or body control module (BCM) was replaced and were not linked, this may set the DTC. Performing the link procedure will assure that all controllers are linked together.
Step | Action | Yes | No |
|---|---|---|---|
Schematic Reference: Theft Deterrent System Schematics | |||
1 | Was the Diagnostic System Check - Engines Controls performed? | Go to Step 2 | Go to Diagnostic System Check - Engine Controls in Engine Controls |
Using Tech 2, inspect for DTC P1626, and P1630. Are both DTCs set? | Go to Step 3 | Go to Step 5 | |
3 |
Was a problem found and verified? | Go to Step 6 | Go to Step 4 |
4 | Replace PIM. Refer to Is the repair complete? | Go to Step 6 | -- |
Does vehicle crank and start? | Go to Step 6 | Go to Diagnostic System Check - Engine Controls in Engine Controls | |
6 |
Does Tech 2 indicate that this DTC reset? | Go to Step 2 | Go to Step 7 |
7 | Using Tech 2, inspect for any other DTCs. Does Tech 2 display any DTCs that you have not diagnosed? | System OK | |
