Fuel System Electrical Test - Isuzu 1999 RODEO Workshop Manual

Circuit Description
When the ignition switch is first turned ON, the powertrain
control module (PCM) energizes the fuel pump relay
which applies power to the in–tank fuel pump. The fuel
pump relay will remain ON as long as the engine is
running or cranking and the PCM is receiving 58X
crankshaft position pulses. If no 58X crankshaft position
pulses are present, the PCM de–energizes the fuel pump
relay within 2 seconds after the ignition is turned ON or the
engine is stopped.
The fuel pump delivers fuel to the fuel rail and injectors,
then to the fuel pressure regulator. The fuel pressure
regulator controls fuel pressure by allowing excess fuel to
be returned to the fuel tank. With the engine stopped and
ignition ON, the fuel pump can be turned ON by using a
command by the Tech 2.
RODEO X22SE 2.2L ENGINE DRIVEABILITY AND EMISSION

FUEL SYSTEM ELECTRICAL TEST

Diagnostic Aids
An intermittent may be caused by a poor connection,
rubbed–through wire insulation, or a wire broken inside
the insulation. Check for the following items:
f Poor connection or damaged harness – Inspect the
PCM harness and connectors for improper mating,
broken locks, improperly formed or damaged
terminals, poor terminal–to–wire connection, and
damaged harness.
Test Description
Number(s) below refer to the step number(s) on the
Diagnostic Chart:
2. If the fuel pump is operating but incorrect pressure
is noted, the fuel pump wiring is OK and the "Fuel
System Pressure Test" chart should be used for
diagnosis.
6E1–87
D06RX040