Broken Locks, Improperly Formed Or Damaged; Terminals, Poor Terminal-To-Wire Connection, And Damaged Harness - Isuzu C22NE Workshop Manual

Circuit Description
When the ignition switch is first turned ON, the engine
control module (ECM) 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 ECM is receiving 58X
crankshaft position pulses. If no 58X crankshaft
position pulses are present, the ECM 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
Battery Joint Cable
Fuel
Pump
Relay
Fuel Pump Fuse
20A
Fuel
Injectors
0.5
M
P/W
A13
Engine
Control
Module
(ECM)
FUEL SYSTEM ELECTRICAL TEST
DRIVEABILITY AND EMISSIONS 6E1-113
Engine
Fuse
15A
Canister Purge
Control Solenoid Valve
0.85 1.25
B/Y R/W
E16 A4
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 scan tool.
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:
• Poor connection or damaged harness - Inspect the
ECM harness and connectors for improper mating,

broken locks, improperly formed or damaged

terminals, poor terminal-to-wire connection, and
damaged harness.
ECM
Fuse
15A
1.25
R/W
A5