For 1990-2009 cars

### Electrical Power Management

The electrical power management (EPM) is used to monitor and control the charging system and alert the driver of possible problems within the charging system. The EPM system makes the most efficient use of the generator output, improves the battery state of charge (SOC), extends battery life.

The idle boost operation is a means of improving generator performance during a low voltage or low battery SOC condition.

Idle boost is activated in incremental steps, idle boost 1 must be active before idle boost 2 can be active. The criteria used by the body control module (BCM) to regulate EPM are outlined below:

Function | Battery Temperature Calculation | Battery Voltage Calculation | Amp-hour Calculation | Action Taken
--- | --- | --- | --- | ---
Idle Boost 1 Start | Less Than -15°C (5°F) | Less Than 13 V | -- | First level Idle boost requested
Idle Boost 1 Start | -- | -- | Battery has a net loss greater than 0.6 AH | First level Idle boost requested
Idle Boost 1 Start | -- | Less Than 11 V | -- | First level Idle boost requested
Idle Boost 1 End | Greater Than -15°C (5°F) | Greater Than 12 V | Battery has a net loss less than 0.2 AH | First level Idle boost request cancelled
Idle Boost 2 Start | -- | -- | Battery has a net loss greater than 1.6 AH | Second level Idle boost requested
Idle Boost 2 Start | -- | Less Than 11 V | -- | Second level Idle boost requested
Idle Boost 2 End | -- | Greater Than 12 V | Battery has a net loss less than 0.8 AH | Second level Idle boost request cancelled
Idle Boost 3 Start | -- | -- | Battery has a net loss of 10 AH | Third level Idle boost requested
Idle Boost 3 Start | -- | Less Than 11 V | -- | Third level Idle boost requested
Idle Boost 3 End | -- | Greater Than 12 V | Battery has a net loss of less than 6 AH | Third level Idle boost request cancelled