Driver Information

Circuit Chart:

CIRCUIT CHART
Circuit assignments for the Body Control Module (BCM) relating to driver information:

LOW BRAKE FLUID
Under low brake fluid conditions, the brake fluid switch closes. When closed, the brake fluid switch grounds circuit 333. The BCM responds by sending a serial data message to the Instrument Panel Cluster (IPC) to turn On the brake telltale.

COOLANT LEVEL
When engine coolant is at the proper level, the low coolant switch is closed. When in this condition, battery voltage is applied to the low coolant circuit 1478 input of the BCM.

When coolant is below the proper level, the low coolant switch opens. Because no voltage is applied to circuit 1478 the BCM responds by sending a serial data message to the instrument panel cluster to turn On the low coolant telltale.

The BCM has an internal timer, which will not turn On the low coolant telltale unless the coolant level is low for greater than 30 seconds. The timer avoids coolant sloshing falsely turning On the low coolant telltale.

OIL LIFE RESET
The change oil soon telltale is reset by depressing the oil life reset push button switch. This switch is located in the underhood junction block. Pressing this switch grounds circuit 1579. When grounded, the BCM requests the engine controller to perform an oil life reset. When reset is completed, the BCM will turn Off the change engine oil telltale.

FUEL LEVEL
The BCM receives fuel level data from the ECM for V6 over CAN and from the PCM for L4 over Class 2. The BCM calculates the data and sends the result to the cluster Class 2 to control the fuel gauge deflection.

ODOMETER
The BCM calculates vehicle mileage from rolling count data sent to the BCM by CAN message from the ECM on V6, and by Class 2 message from the PCM on L4 vehicles. The BCM sends the mileage data to the cluster over Class 2 to display the vehicle mileage.

If the BCM is dead and is replaced in the field, the last value displayed by the cluster must be entered into the new BCM with the service tool during reprogramming.