Powertrain Control Module (PCM)

The Powertrain Control Module (PCM) is located on the lower left side of the instrument panel.

The PCM communicates with the body control module (BCM) via serial data over the class 2 serial data bus, CKT 1807. When the BCM determines a passed theft condition, the BCM sends a coded password to the PCM. When the PCM receives the correct password, the PCM enables the fuel injection system, allowing the vehicle to operate correctly. The PCM may allow the car to start and quickly stall during a failed theft condition.

The following conditions may cause the PCM to enter a tamper mode:
^ A bad timing cycle
^ An incorrect password

If the BCM does not receive a password within a preset time window, the BCM will enter a short tamper mode. During this mode, the PCM will not allow the car to operate for 4 seconds.

If the password is incorrect, the PCM will enter the long tamper mode. In the long tamper mode, the following actions will occur:
^ The THEFT SYSTEM indicator will flash.
^ The fuel injectors will be shut off for approximately 10 minutes.

Although the vehicle may start, the engine will quickly stall due to a fuel cut-off.

In the event of an open in the serial data communication between the BCM and the PCM, the following actions occur:
^ The PCM will become fail-enabled if the car has already passed theft for that ignition cycle (i.e. the engine is running).
^ The PCM may set the diagnostic trouble codes (DTC).
^ The THEFT SYSTEM indicator will light continuously.
^ The PCM will become fail-enabled for future ignition cycles.

If a failure occurs in serial data before the ignition cycle, while the PCM is not fail-enabled, the PCM will never receive a valid password in order to enable the continued use of the fuel injectors.