Isuzu 1999 RODEO Workshop Manual page 1750

Legend
(1) Vent Solenoid
(2) EVAP Purge Solenoid
(3) Throttle Body
(4) Fuel Filler Neck
(5) Fuel Tank
(6) Rollover Valve
(7) EVAP Canister
(8) Ignition Feed
(10) EVAP Purge Solenoid Driver Signal from PCM
Electrical Components
The electrical components that make up the enhanced
EVAP system are:
f Fuel Tank Pressure Sensor. The fuel tank pressure
sensor is a three-wire strain gauge sensor similar to a
common MAP sensor.
pressure sensor has very different electrical
characteristics due to its pressure differential design.
The sensor measures the difference between the air
pressure (or vacuum) in the fuel tank and the outside
air pressure.
The sensor mounts at the top of the fuel pump
assembly. A three-wire electrical harness connects it to
the PCM. The PCM supplies a five-volt reference
RODEO 6VD1 3.2L ENGINE DRIVEABILITY AND EMISSIONS
However, the fuel tank
(11) Vent Solenoid Driver Signal from PCM
(12) Vent Filter
(13) Fuel Tank Pressure Sensor
(14) Fuel Tank Pressure Signal to PCM
(15) 5 Volt Reference "A" Circuit from PCM
(16) Sensor Ground Circuit from PCM
(17) Fuel Level Sensor
(18) Fuel Level Signal to PCM
(19) 5 Volt Return
voltage and a ground to the sensor. The sensor will
return a voltage between 0.1 and 4.9 volts. When the
air pressure in the fuel tank is equal to the outside air
pressure, such as when the fuel cap is removed, the
output voltage of the sensor will be 1.3 to 1.7 volts.
When the air pressure in the fuel tank is 4.5 in. H2O
(1.25 kPa), the sensor output voltage will be 0.5 0.2 V.
When there is neither vacuum nor pressure in the fuel
tank, the sensor voltage will be 1.5 V. At –14 in. H2O
(–3.75 kPa), the sensor voltage will be 4.5
6E2–507
C06RW006
0.2 V.