Maserati Ghibli M157 Quattroporte Body Control Module BCM Programming Service P68226670AA

The electronic functions of the Body Control Module (BCM) it supports or controls include the following:

Brake Fluid Level: The BCM constantly checks the brake fluid level sensor via a hard-wired input. Based on the sensor’s signal, the BCM sends an electronic message over the CAN data bus to the Instrument Cluster (IC), turning on the Low Fluid indicator.

Enhanced Accident Response Support: The BCM receives signals from the Occupant Restraint Controller (ORC) and, after an airbag deployment, it deactivates the power lock output, unlocks all doors by activating the power unlock output, and reactivates the power lock output if no further action is taken within two seconds. The BCM also works with the Powertrain Control Module (PCM) to turn on interior lighting after a deployment event, ten seconds after the vehicle stops moving. The lights stay on until the ignition is turned off. These Enhanced Accident Response System (EARS) features depend on the vehicle’s electrical system working after an impact.

Exterior Lighting Switch Support: The BCM monitors the headlamp switch position to turn the exterior lights on or off. It reads the input from the switch and controls the right and left park lamps, high/low beams, and sends a message to the IC for the high beam indicator. If the vehicle has automatic headlights, the BCM uses data from the HVAC control module and rain sensor to automatically turn the lights on and off when the ignition is on.

Fuel Level Data Support: The BCM receives an analog input from the fuel level sending unit and transmits this data over the CAN bus for use by other modules. The IC uses this data to adjust the fuel gauge and activate the low fuel indicator.

Hazard Lamp Circuit Control: The BCM reads the hazard switch input and controls the park lamps accordingly, sending a message to the IC to manage the hazard light indicators.

Headlamp Washer Control: For vehicles with headlamp washers, the BCM controls the relay in the Power Distribution Center (PDC) based on CAN data bus messages.

Ignition Relay Control: The BCM receives ignition status messages from the CAN bus and an input from the ignition switch, using this information to control the ignition ON and ACCESSORY/ON relays in the Power Distribution Center (PDC).

Interior Lamp Load Shedding: The BCM has a battery saver feature that automatically turns off interior lights if they’ve been on for about eight minutes.

Interior Lighting Control: The BCM manages interior lighting based on inputs from various switches and sensors, including door and liftgate ajar switches. It also controls features like timed illuminated entry and theater-style fade-to-off.

Local Interface Network Master Module: The BCM serves as the master module for the LIN data bus, collecting data from the compass sensor and Intelligent Battery Sensor (IBS), and either acting on the information or sending it to other modules.

Power Inverter Support: The BCM monitors the power inverter’s status via a hard-wired input, transmitting this information to other vehicle modules over the CAN bus.

Power Lock System Control: The BCM controls the power lock system based on inputs from lock switches and the RF hub, including functions like automatic door locks, unlock, and RAM box or tailgate locks.

Remote Radio Switch Support: The BCM processes signals from the steering wheel’s remote radio switches and sends the appropriate radio control messages over the CAN bus.

Remote Start System Support: The BCM receives inputs from the RF hub and displays remote start system messages on the EVIC.

Shipping Mode: In vehicles with a telematics platform, the BCM has a "Shipping Mode" to replace the IOD fuse when the vehicle is transported or stored for a long period.

Steering Wheel Switch Support: The Steering Column Control Module (SCCM) receives input from steering wheel switches via the CAN bus to control and configure the EVIC displays and functions.

Vehicle Theft Security System Control: The BCM monitors inputs from door ajar switches and the RF hub, activating the Vehicle Theft Security System (VTSS) alarm features when triggered.

Washer Fluid Level: The BCM monitors the washer fluid level sensor and sends a message to the IC to turn on the Low Washer Fluid indicator when the level is low.

DESCRIPTION

The Body Control Module (BCM) is an electronic control unit containing a microcontroller that manages many key body-related electronic functions and features in the vehicle. While some of these functions rely on direct hardwired inputs and outputs, most are made possible or enhanced through electronic communication between the BCM and other vehicle modules, as well as a diagnostic scan tool, via the Controller Area Network (CAN) data bus.

The BCM serves as a gateway between the high and low-speed CAN data bus networks and acts as the master node for the Local Interface Network (LIN). This setup allows for the sharing of sensor data, which helps simplify the vehicle's wiring, reduce the load on internal controllers and sensors, and improve reliability. It also enables enhanced diagnostics and the addition of new features. The BCM uses this communication to acquire vehicle configuration data, including customer-programmable features.

OPERATION

The BCM utilizes On-Board Diagnostics (OBD) to monitor all systems and circuits it controls, setting active and stored Diagnostic Trouble Codes (DTC) when faults are detected. It can also send electronic requests to the Instrument Cluster (IC) to display specific warning messages related to certain faults or conditions.

While the BCM’s hardwired inputs and outputs can be diagnosed using traditional tools and methods (refer to the wiring information), diagnosing its electronic controls or communication between modules requires a diagnostic scan tool for accuracy. For proper diagnosis of BCM-controlled systems and their communications, refer to the relevant diagnostic guidelines.

NOTE: There are no serviceable fuses or relays in this BCM.

Battery Saver Mode / Battery Saver On Message — If Equipped

The Intelligent Battery Sensor (IBS) communicates with the BCM over the Local Interface Network (LIN) bus, providing data such as battery voltage, temperature, and State Of Charge (SOC). The BCM uses this data to determine load shedding strategies.

When certain conditions are met, the BCM activates load shedding, reducing electrical loads to preserve battery life. The BCM sends load-shed messages via the CAN bus and works with secondary control devices to turn off specific loads. This process ensures stability and minimizes driver concerns.

For load shedding to begin, three conditions must be met:

1. The engine must be running.
2. The battery SOC must be 70% or lower.
3. The battery voltage must be 12.2 V or less.

Once these conditions are met, the BCM begins the load-shedding operation, and the Battery Saver On message appears on the Instrument Panel Cluster (IPC), alerting the driver. The following sequence of load shedding occurs:

• Level 1: No action (reserved for future use).
• Level 2: If the battery loses 7.5 amp-hours (Ah), heated seats and the heated steering wheel are reduced (if equipped).
• Level 3: At 10 Ah loss, heated/cooled cupholders are turned off (if equipped).
• Level 4: At 12.5 Ah loss, rear defroster and heated mirrors are turned off.
• Level 5: At 15 Ah loss, HVAC system reduces load.
• Level 6: At 17.5 Ah loss, the power inverter system turns off (if equipped).
• Level 7: At 20 Ah loss, audio and telematics systems reduce load.

Charging System:

The charging system operates independently of load shedding and continuously performs diagnostics on itself. If the Charging System Light turns on, it may indicate a problem with the charging system.

Loss of battery charge may be caused by:

1. The charging system being unable to meet the electrical demands due to excessive loads, though it’s still functioning.
2. High electrical load from things like HVAC max settings, lights, overloaded power outlets, and accessories during specific driving conditions (e.g., city driving, towing).
3. Additional installed options (e.g., extra lights, audio systems).
4. Short driving cycles, prolonged vehicle parking, or recent battery replacement.
5. Leaving electrical loads on when parked, such as lights or radio.
6. Using the battery for auxiliary functions during parking (e.g., powering a vacuum, game console, etc.).