PCM monitors fuel tank pressure sensor signal to detect
vacuum decay and excess vacuum during the enhanced EVAP diagnostic.
Fuel tank pressure sensor measures the difference between air pressure
(or vacuum) in the tank and the outside air pressure. PCM applies 5-
volt reference and ground to the sensor. Sensor will return a signal
voltage between 0.1-4.9 volts. If PCM detects a fuel tank pressure
sensor signal that is excessively low, DTC will set.
You likely won't notice any drivability problems.
Fuel tank pressure sensor signal is less than 0.1 volt.
Check for poor terminal connections at fuel tank pressure
Check for shorts.
Check for damaged harness.
Replace fuel tank pressure sensor.
Dan SAVING THE WORLD ONE BONNEVILLE AT A TIME
1997,1998,2000,2005 year confused Bonneville SSExi. Stock? ish.