An apparatus for collecting data related to the internal pressure of a fuel tank in a motor vehicle includes an analog pressure transducer that outputs a signal to charge a capacitor to a level proportional to the pressure in the fuel tank of the vehicle. A programmable microprocessor signals a gate to open a communication path between the capacitor and a discharge resistor, then monitors the number of clock counts that occur before the voltage across the discharge resistor drops below a reference voltage. The microprocessor uses the clock count to determine the absolute pressure within the fuel tank and transmits it to a central vehicle computer via a multiplexed data bus system.