Serial Data Power Mode Master
WARNING: This page is about a different car, the 2005 Saturn L300. However, it is still accessible from the selected car via links, so may be relevant.
On vehicles that have several control modules connected by serial data circuits, one module is the power mode master (PMM). On this vehicle the PMM is the body control module (BCM). The PMM receives 4 discrete ignition switch signals to differentiate which power mode will be sent over the Serial Data circuits. The table below illustrates the state of these inputs in correspondence to the ignition switch position and one additional circuit for transmission control:
5-Wire Ignition Switch Table
| Ignition Switch Position | IGN 0/ACCESSORY/RUN/START | IGN 1/RUN/START | IGN 2/ACCESSORY/RUN | IGN 3/RUN | START | Power Mode Transmitted |
|---|---|---|---|---|---|---|
| Off | 0 | 0 | 0 | 0 | 0 | OFF/Awake |
| Start | 1 | 1 | 0 | 0 | 1 | Crank |
| Accessory | 1 | 0 | 1 | 0 | 0 | Accessory |
| Run | 1 | 1 | 1 | 1 | 0 | Run |