GM Service Manual Online
For 1990-2009 cars only
Table 1: Hybrid Control Module (HCM)
Table 2: Energy Storage Control Module (ESCM)
Table 3: Starter/Generator Control Module (SGCM)

Hybrid Control Module (HCM)

Scan Tool Output Control

Additional Menu Selection(s)

Description

Auxiliary Coolant Pump Relay

--

When the aux coolant pump relay is commanded on, the relay will be activated and the aux coolant pump will be turned on. When the aux coolant pump relay is commanded off, the relay will be deactivated and the aux coolant pump will be turned off.

Auxiliary Trans Pump Relay

--

When the aux trans pump relay is commanded on, the relay will be activated and the aux trans pump will be turned on. When the aux trans pump relay is commanded off, the relay will be deactivated and the aux trans pump will be turned off.

Auxiliary Power Outlet (APO) Switch Indicator

--

If the APO switch indicator is commanded on, the APO switch indicator (lamp) will illuminate with 100% illumination (no dimming). When the APO switch indicator is commanded off, the APO switch lamp well be turned off.

Power Maintain Relay

--

Used to enable and disable the power maintain relay which powers specific hybrid systems.

Idle Engine Off (IEO) Command

--

If the IEO command is on, and the following conditions exist, the HCM will initiate the idle engine off event.

    • Vehicle speed = 0.
    • Vehicle is in Park or vehicle is in D4 & brake is applied.
    • Accelerator pedal is released.
    • Not currently in an APO condition (normal or continuous).

When IEO command is off, an auto-start (exit out of IEO) will not be initiated unless a key crank command occurs or an auto-start command is received.

Auto Start Command

--

If auto-start command is on, and the following conditions exist, the HCM will initiate an engine re-start (auto-start) event:

    • Vehicle speed =0.
    • Vehicle is in Park.

When auto-start command is off, the HCM shall cancel the auto-start is the engine has yet to start.

Disable Idle Engine Off (IEO)

--

When the disable idle engine off command is on, the HCM disable entry into IEO. When disable idle engine off command is off the HCM shall allow IEO.

14 V-42 V Command

--

Commanding the APM converter to transfer power from the 12 V Battery to the 42 V Battery Pack.

42 V-14 V Command

--

Commanding the APM converter to transfer power from the 42 V Battery Pack to the 12 V Battery.

Energy Storage Control Module (ESCM)

Scan Tool Output Control

Additional Menu Selections

Description

Battery Pack Fan Speed

--

When commanded on, the fan speed will operate at 100%. When commanded off, the fan speed will be 0%.

Battery Pack Cut-Off Switch

--

A command of closed represents that the battery pack cut-off switch will allow current to flow between the SGCM and the battery pack. A command of open, does not allow current to flow between the SGCM and the battery pack when the following condition exist:

  • Engine Speed = 0

Reset Battery Total AHRS (Amp Hours)

--

A command of "Reset" indicates that the ESCM shall set the values of Battery Pack Total Ahrs Discharged and Battery Pack Total Ahrs Charged to Zero. A command of "Don't Reset" indicates that the ESCM shall not change the values of Battery Pack Total Ahrs Discharged and Battery Pack Total Ahrs Charged.

ESCM Service Charge

--

A command of "On" indicates that the ESCM shall initiate its portion of the Battery Pack Service Charge Procedure once the Ignition Switch is turned to the OFF/LOCK position. A command of "Off" indicates that the ESCM shall not initiate its portion of the Battery Pack Service Charge Procedure.

Starter/Generator Control Module (SGCM)

Scan Tool Output Control

Additional Menu Selections

Description

SGCM Pump Speed

--

A command of On indicates that the SGCM Coolant Pump will operate at its maximum speed.

SGCM Service Charge

--

A command of "On" indicates that the SGCM shall initiate its portion of the Battery Pack Service Charge Procedure once the Ignition Switch is turned to the OFF/LOCK position. A command of "Off" indicates that the SGCM shall not initiate its portion of the Battery Pack Service Charge Procedure.

SGCM Fan Speed

--

A value of "High" indicates that the SGCM Coolant Fan will operate at its maximum speed. A value of "Low" indicates that the SGCM Coolant Fan will operate at a speed equivalent to 9 Volts being applied to the Fan.

SGCM Key Crank Speed

--

This command represents the control parameter which indicates the desired speed that the engine will turn at during a Key Crank event once the Key Crank Speed - Enable is selected.