Serial Data Power Mode Master
WARNING: This page is about a different car, the 2010 Pontiac G5 and 2010 Chevrolet Cobalt. 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 3 discrete ignition switch signals to differentiate which power mode will be sent over the Serial Data circuits. The 3-wire Ignition Switch table below illustrates the state of these inputs in correspondence to the ignition switch position:
3-Wire Ignition Switch
| Ignition Switch Position | Accessory | Ignition 1 | Off/Run/Crank | Power Mode Transmitted |
|---|---|---|---|---|
|
IMPORTANT:
States marked with the * indicate a derived positive voltage level of 3 volts. States marked with the ** indicate a derived positive voltage level of 4 volts.
|
||||
| Off | 0 | 0 | 0 Key out. 1 Key in. | OFF/Awake or RAP |
| Start | 0 | 1 | 1 * | Crank |
| Accessory | 1 | 0 | 0 | Accessory |
| Run | 1 | 1 | 1 ** | Run |