Chevrolet Equinox Service Manual: Power Mode Description and Operation

Serial Data Power Mode MasterPower Moding Block Diagram

K9Body Control ModuleKR76Retained Accessory Power RelayKR73Ignition Main RelayKR104ABattery Saver Relay 1S39Ignition SwitchK20Engine Control ModuleKR75Engine Controls Ignition RelayHard-Wired

Serial Data

K9-Body Control Module

KR76-Retained Accessory Power Relay

KR73-Ignition Main Relay

KR104A-Battery Saver Relay 1

S39-Ignition Switch

K20-Engine Control Module

KR75-Engine Controls Ignition Relay

Power to many of this vehicles circuits is controlled by the module that is designatedthe power mode master. This vehicles power mode master is the body control module(BCM). The BCM has multiple B+ circuits that feed into it. Each of those circuitsare partitioned within the controller to drive certain outputs of the vehicle’s bodyfunctions. An open or short in any one of the B+ circuits may induce multiple codes/ora section ofnon-functionality within the BCM with the rest of the BCM functioning normally. Inthis case it is useful to refer to the power distribution schematics to determineif the non-functional partition of the controller shares a common B+ circuit. Theignition switch is a low current switch with multiple discrete ignition switch signalsto the power mode master for determination of the power mode that will be sent overthe serial data circuits tothe other modules that need this information. The power mode master will also activaterelays and other direct outputs of the power mode master as needed. The power modemaster determines which power mode (Off, Accessory, Run, Crank Request) is required,and reports this information to other modules via serial data. Modules which haveswitched voltage inputs may operate in a default mode if the power mode serial datamessage does not matchwhat the individual module can see from its own connections.

The power mode master receives ignition switch signals to identify the operators desiredpower mode. The Power Mode Parameters table below illustrates the correct state ofthese input parameters (circuits) in correspondence to the ignition switch position:

Power Mode Parameters

Ignition Switch Position

Power Mode Transmitted

Ign. Off/Run/Crank

(Off/Run Crank Voltage Circuit)

Ignition Accessory/Run

(Accessory Voltage Circuit)

Ignition Run/Crank

(Ignition 1 Voltage Circuit)

Off Key Out	Off	Key Out / ACC	Inactive	Inactive
Off Key IN	Off	Key In / Off	Inactive	Inactive
Accessory	Accessory	Key Out / ACC	Active	Inactive
Run	Run	Run	Active	Active
Start	Crank Request	Crank	Inactive	Active

Relay Controlled Power Mode

The BCM uses the discrete ignition switch inputs Off/Run/Crank Voltage, AccessoryVoltage, and Ignition-1 Voltage, to distinguish the correct power mode. The BCM, afterdetermining the desired power mode, will activate the appropriate relays for thatpower mode.

The retained accessory power relay remains on for a timed period after the Ignitionkey is removed. Refer toRetained Accessory Power Description and Operationfor more information on the retained accessory power function.

Push Button Start (If Equipped)

The ignition mode switch has 2 LEDs that indicate the vehicle power mode. When thevehicle is in the off mode, both LED’s will be off. Pressing the ignition mode switchbutton once (without the brake pedal applied), the vehicle enters the accessory modeand the amber LED (ACC) will illuminate. The accessory mode has a 5 minute timeoutto reduce battery drain. Pressing the ignition mode switch button a second time (withoutthe brake pedalapplied), the vehicle enters the run/start mode (without the engine running) and thegreen LED (Run/Start) will illuminate. With the ignition off (without the brake pedalapplied) and pressing and holding the push button start switch for up to 10 secondswill place the vehicle in run/start mode (without the vehicle running) and the greenLED (Run/Start) will illuminate. With the ignition off (with the brake pedal applied),pressing the ignitionmode switch button once, the vehicle will enter run/start mode and the green LED (run/start)will illuminate. This will start the engine. Both LED’s have the voltage suppliedfrom the body control module (BCM). The ignition mode switch sends the ignition modeswitch status to the passive entry passive start module (PEPS) and to the BCM. ThePEPS module sends a redundant signal to the BCM with the ignition mode switch status.

Battery Saver Mode (Transport Mode) (If Equipped)

The battery saver mode (transport mode) reduces the parasitic load of some modulesduring overseas shipment or during vehicle storage conditions. This improves the draintime on the battery (up to 70 days without the battery going dead). When the vehicleis in transport/storage, some features may have reduced functionality while in thebattery saver mode (transport mode), such as disabling the Remote Function Actuatoror content theftfeatures.

The battery saver mode (transport mode) incorporates a latching relay that when enableddisconnects some modules from their ignition power or memory power sources. Batterysaver mode (transport mode) is initiated by turning on the hazard flashers and thenturning the ignition key into the crank position or pushing the push button startswitch (if equipped) for greater than 15 seconds. The mode is disengaged by repeatingthe previous processcausing the relay to latch in the other direction. After battery saver mode (transportmode) has been enabled, the BCM may not send the command to unlatch the relay untilafter the ignition has been switched to the off position for up to 1 minute. In batterysaver mode (transport mode) the BCM will send a command to latch the relay for operationof those modules while the ignition is in the run position and then again unlatchingthe relay afterthe ignition is turned off. The DIC (if equipped) will display Transport Mode is Onwhen the transport mode is enabled and Transport Mode is Off when the transport modeis disabled. For vehicles not equipped with a DIC, the battery indicator light willconstantly flash on the Instrument Cluster when transport mode is enabled. Once thevehicle is running and the hazard flashers are on, turning the ignition key into thecrank position or pushingthe push button start switch (if equipped) for greater than 15 seconds will latchthe relay in the other direction. This feature can be used as many times as necessaryif the vehicle is to be stored for an extended period of time.

BCM Awake/Sleep States

The BCM is able to control or perform all of the BCM functions in the awake state.The BCM enters the sleep state when active control or normal monitoring of systemfunctions has stopped and a time limit has passed. The BCM must detect certain wake-upinputs before entering the awake state. The BCM monitors for these inputs during thesleep state.

The BCM will enter the awake state if any of the following wake-up inputs are detected:

Activity on the serial data lineDetection of a battery reconnectAny door open signalHeadlamps ONKey-in-ignitionIgnition ONPark lamps ONKeyless entry or remote start message

The BCM will enter a sleep state when all of the following conditions exist:

The ignition switch is OFF, key out.No activity exists on the serial data line.No outputs are commanded.No delay timers are actively counting.No wake-up inputs are present.

If all these conditions are met, the BCM will enter a low power or sleep condition.