This "sense" is just an input to the logic module that is connected to the battery voltage and is used to control the voltage regulator for the alternator field coil. 1984 models did not have this input because they had an external voltage regulator connected to the alternator directly.
60 seconds after engine startup, if the voltage sense input is below 4V, the system enters limp-in mode, the power loss light is turned on, and a fault code 16 is stored. The alternator field coil driver will enter a fixed, 25% duty cycle to prevent overcharging of the battery, but allow the vehicle to operate. If the voltage sense input is between 4V and 8.5V, the logic module will full-field (100% duty cycle) the alternator field coil for 20 seconds. If the voltage sense input is still below 8.5V, the system enters limp-in mode, the power loss light is turned on, and a fault code 16 is stored. The alternator field coil driver will enter a fixed, 25% duty cycle.
If the voltage sense input is more than 1V above the target charging voltage (as determined by the battery temperature sensor) for more than 20 seconds, the power loss light is turned on and a fault code 46 is stored. The power loss light will turn off if the voltage drops below 1V of the target voltage.
After the engine has been running for six minutes, the coolant temperature is above 160^F, and the engine speed is above 1500 rpm, if the voltage sense input is more than 1V below the target charging voltage for more than 20 seconds, a fault code 47 is stored.
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Updated 12/19/2003.
Copyright © 1996-2003 Russ W. Knize.