ECM and TCM Power Mode Backup Strategy
WARNING: This page is about a different car, the 2006 Cadillac STS. However, it is still accessible from the selected car via links, so may be relevant.
The ECM and TCM remain in the last known power mode state until it can determine its backup system power mode based on their discrete Accessory voltage and Run/Crank Ignition 1 voltage inputs.
Power Mode Description and Operation
| Accessory Voltage State | Run/Crank Ignition 1 Voltage State | Power Mode Determined |
|---|---|---|
| Inactive | Inactive | Off |
| Active | Inactive | Accessory |
| Active | Active | Run |
| Inactive | Active | Crank |