Refer to
Power, Ground, MIL, DLC
,
DLC Schematic
in Data Link Communications, and
Pass Key III Module
in Theft Deterrent.
Circuit Description
The vehicle theft deterrent (VTD) module produces the theft deterrent fuel enable signal when ignition is ON and the proper key resistor pellet is detected. The powertrain control module (PCM) monitors the fuel enable signal during crank. If the proper signal is present on the Class II Serial Data Circuit, the PCM enables the fuel delivery in order to allow the engine to start. If the PCM detects an incorrect password (theft deterrent system failure or attempted vehicle theft, DTC 1631 is set. The engine may not start or crank as long as the condition is present. Refer to Vehicle Theft Deterrent (VTD) Description and Vehicle Theft Deterrent (VTD) Operation .
Conditions for Running the DTC
The ignition is ON.
Conditions for Setting the DTC
| • | The PCM is detecting an incorrect password from the VTD system. |
| • | The conditions is present for less than 1 second. |
Action Taken When the DTC Sets
The PCM stores conditions which were present when the DTC set as Failure Records only. This information will not be stored as Freeze Frame Records.
Conditions for Clearing the MIL/DTC
| • | The DTC becomes history when the conditions for setting the DTC are no longer present. |
| • | The history DTC clears after 40 malfunction free warm-up cycles. |
| • | The PCM receives a clear code command from the scan tool. |
Diagnostic Aids
DTC P1631 indicates that the vehicle theft deterrent password that the PCM has learned does not agree with the password being received from the theft deterrent system. This condition can occur if an incorrect key is being used when attempting to start the vehicle or if the Theft Deterrent Module has been replaced and the PCMs password learn function has not been enabled.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Did you Preform the Powertrain On-Board Diagnostic (OBD) System Check? | -- | ||
2 | Perform the password learn procedure. Refer to Programming Theft Deterrent System Components in Theft Deterrent. Can the password learn procedure be performed successfully? | -- | System OK |
