Hybrid Powertrain Control Module

Location 

The hybrid powertrain control module is a non-serviceable, flash-programmable micro-processor contained within the power inverter module.

Operating Functions 

The hybrid powertrain control module is the main controller of powertrain operation. The hybrid powertrain control module determines when to perform normal operating modes such as electric mode, extended range mode, and regenerative braking. The hybrid powertrain control module also operates in conjunction with the hybrid powertrain control module 2 to determine when to enable and disable the DC high voltage circuits. Each motor control module operates the applicable motor based upon hybrid powertrain control module commands.

Communication and Hosted Diagnostics 

The hybrid powertrain control module is the host controller for DTC information for the following control modules:

• 14V power module
• Motor control module 1
• Motor control module 2
• Auxiliary transmission fluid pump motor control

These modules diagnose their own operation and determine when a fault condition is present. The 14V power module communicates diagnostic status to the hybrid powertrain control module over serial data.

All 3 motor control modules and the hybrid powertrain control module exchange information and commands on a serial peripheral interface bus internal communication circuit as well as the hi-speed hybrid GMLAN communication circuit.

In the event a hosted module communicates a fault condition, the hybrid powertrain control module will determine if one or more operating modes are affected and notify the vehicle operator by requesting the MIL illuminate and/or by displaying a message in the Driver Information Center. In addition, the hybrid powertrain control module will store the associated DTC information for retrieval by a scan tool. Some hosted modules may require an ignition cycle to clear certain DTCs from the hybrid powertrain control module.

Circuit Inputs 

In addition to data parameters, the hybrid powertrain control module directly monitors the following signal circuits:

• Transmission shift selector internal mode switch direction and Park/Neutral switch signals
• Engine crankshaft position sensor signal
• High voltage interlock circuit