Gauges Cluster
FUEL GAGEThe FUEL Gage uses a three-terminal Fuel Level Sensor. One terminal is tied to ground, one terminal is tied to ignition voltage, and the third terminal is the sensing line which is tied to the Body Computer Module (BCM). With a full fuel tank, the fuel tank float moves the sensing line voltage close to battery voltage. If the fuel tank is near empty, the float moves the sensing line voltage closer to zero. The BCM turns this analog voltage to a digital voltage. This signal is sent to the Instrument Panel Cluster over the Serial Data Line. The BCM also compares the voltage at terminal 3C4, the Ignition 1 Input (BD50), with the Fuel Level Input (BD40) so that changes in system voltage do not affect the accuracy of the FUEL gage.
OIL GAGE
The BCM monitors oil pressure at terminal 3C3, the Oil Pressure Input (BD71). This analog voltage is converted to a digital signal and sent through the Serial Data Line to the IPC.
SPEEDOMETER, ODOMETER AND TRIP ODOMETER
The Vehicle Speed Sensor (VSS) sends electrical pulses to the PCM at the rate of 40,000 pulses per mile. The PCM buffers this signal and sends it to the BCM. The BCM computes speed and total miles traveled. Odometer data is stored in the non-volatile memory. Trip Odometer data is stored in the resettable keep alive memory. The BCM sends Data Line Information to the IPC. Vehicle speed, total accumulated miles, and trip miles are displayed. The mileage memory is in the Body Computer Module (BCM).
TACHOMETER
The IPC eavesdrops on the PCM to BCM serial data communications for tachometer information.
TEMP GAGE
The PCM monitors Coolant Temperature at terminal 2B9, the Coolant Temperature Input (ED04). This analog voltage is converted to a digital signal and sent through the Serial Data Line to the IPC.
VOLTS GAGE
The BCM monitors system voltage at terminal 3C4, the Ignition input (BD50). This analog voltage is converted to a digital signal and is sent through the Serial Data Line to the IPC.