relay ISUZU TF SERIES 2004 Workshop Manual

6E–270 ENGINE DRIVEABILITY AND EMISSIONS
FUEL PRESSURE RELIEF
Caution: To reduce the risk of fire and personal
injury, it is necessary to relieve the fuel system
pressure before servicing the fuel system
components.
Caution: After relieving the fuel system pressure, a
small amount of fuel may be released when
servicing fuel lines or connections. Reduce the
chance of personal injury by covering the fuel line
fitting with a short towel before disconnecting the
fittings. The towel will absorb any fuel that may leak
out. When the disconnect is completed, place the
towel in an approved container.
1. Remove the fuel filler cap.
2. Remove the fuel pump relay from the underhood
relay box .
3. Start the engine and allow it to stall.
4. Crank the engine for about 30 seconds.
5. Disconnect the negative battery cable.
FUEL RAIL ASSEMBLY
Removal Procedure
NOTE:
Use care when removing the fuel rail assembly in
order to prevent damage to the injector al connector
terminal and the injector spray tips.
Fitting should be capped and holes plugged during
servicing to prevent dirt and other contaminants from
entering open lines and passage.
Important: An eight-digit identification number is
stamped on side of the fuel injector. Refer to this
number when you service the fuel rail or when a
replacement part is required.
1. Disconnect 4 injector connectors.
2. Lift side-clip up on the fuel rail.
3. Disconnect fuel pressure regulator hose.
4. Disconnect wiring harness from the bands on the
fuel rail.
5. Remove the intake pipe.
6. Loosen flare nut.
A. Lift up the injectors carefully to separate them
from intake manifold.
B. Lift up the fuel rail with injectors as assembly.
Do not separate the fuel injectors from fuel rail.
C. If an injector become separated from fuel rail,
injector backup O-ring and injector retainer clip
must be replaced.
D. Drain residual fuel from fuel rail into an
approved container.
7. If removal of fuel pressure regulator is necessary,
Refer to Fuel Pressure Regulator Removal
Procedure.

ENGINE DRIVEABILITY AND EMISSIONS 6E–273
7. Install fuel rail assembly. Tighten the nuts to 19 N·m
(1.9 kgf·m). Refer to Fuel Rail Installation
Procedure.
Tighten the flare nut to 27 - 33 N·m (2.8 - 3.4 kgf·m).
8. Connect the negative battery cable.FUEL PRESSURE REGULATOR
Removal Procedure
Caution: To reduce the risk of fire and personal
injury, it is necessary to relieve the fuel system
pressure before servicing the fuel system
components.
Caution: After relieving the fuel system pressure, a
small amount of fuel may be released when
servicing fuel lines or connections. Reduce the
chance of personal injury by covering the fuel line
fitting with a shop towel before disconnecting the
fittings. The towel will absorb any fuel that may leak
out. When the disconnect is completed, place the
towel in an approved container.
NOTE: Compressed air must never be used to test or
clean a fuel pressure regulator, as damage to the fuel
pressure regulator may occur.
NOTE: To prevent damage to the fuel pressure
regulator, do not immerse the pressure regulator in
solvent.
Removal Procedure
1. Depressurize the fuel system. Refer to Fuel
Pressure Relief Procedure.
2. Disconnect the negative battery cable.
3. Remove the fuel pump relay.
4. Disconnect the vacuum line form fuel pressure
regulator.

6E–274 ENGINE DRIVEABILITY AND EMISSIONS
5. Remove the fuel pressure regulator retaining screw.
6. Remove the fuel pressure regulator from fuel rail.
Installation Procedure
1. Insert the fuel pressure regulator into the fuel rail.2. Install the fuel pressure regulator retaining bracket
and tighten with a screw.
3. Connect vacuum line onto the fuel pressure
regulator.
4. Install the fuel pump relay.
5. Connect the negative battery cable.
6. Crank the engine until it starts. Cranking the engine
may take longer than usual due to trapped air in the
fuel line.
7. Tighten the flare nut to 27 - 33 N·m (2.8 - 3.4 kgf·m).

1-78 HEATER AND AIR CONDITIONING


RTW4A0SH000201

Pressure switch
Disconnect pressure switch connector and check for continuity
between pressure switch side connector terminal.


825r300045


Heater and thermo switch relay.
Check for continuity between the relay terminals.

1 - 5





No continuity
(When battery voltage is applied between 2 - 4 )
1 - 5





Continuity
825r300023

Check for continuity between the relay terminals.
1 - 2





No continuity
(When battery voltage is applied between 3 - 4 )
1 - 2





Continuity

HEATER AND AIR CONDITIONING 1-79

TROUBLESHOOTING
FAN CONTROL KNOB (FAN SWITCH)
Current flows to the blower motor through the Heater & A/C relay (X-11) to activate the rotation of the blower motor
by turning “ON” the fan control knob (fan switch). Blower motor speed is controlled in stages by the resistor, by
operating the switch from “LOW” to “HIGH.”

D08R300046-X2

1-80 HEATER AND AIR CONDITIONING

BLOWER MOTOR DOES NOT RUN


Replace
YES

Is No.SBF-8 (30A) slow blow fuse OK?

Is heater & A/C relay (X-11) OK?
YES

Is resistor OK?
YES

Is fan control knob (Fan switch) OK?
YES
YES

Check to see if battery voltage is present at
chassis side connector terminal No.C105-1 is there a
battery voltage?

Turn the ignition switch "ON" (Engine is running)

Fan control knob (Fan switch) "ON"

Is blower motor OK?
YES
Poor ground or open circuit either between chassis
side connector terminal No.C105-2 and No.C104-3
or No.B13-1 and body ground No.C-109.
NO
Replace
NO
Replace
NO
NO
Replace control lever
assembly
Replace
NO
NO
Open circuit between
No.SBF-8 (30A) slow blow
fuse and No.C105-1.

HEATER AND AIR CONDITIONING 1-87

MAGNETIC CLUTCH
When the A/C switch and the fan control knob (fan switch) are turned on with the engine running, current flows
through the thermostat and the compressor relay to activate the magnetic clutch.
The air conditioning can be stopped by turning off the A/C switch or the fan control knob (fan switch).
However, even when the air conditioning is in operation, the electronic thermostat, the pressure switch or the ECM
is used to stop the air conditioning temporarily by turning off the magnetic clutch in the prearranged conditions to
reduce the engine load which is being caused by the rise in the engine coolant temperature, and the acceleration of
the vehicle, etc.

1-90 HEATER AND AIR CONDITIONING

MAGNETIC CLUTCH DOES NOT RUN (4JA1L/4JH1-TC)



Replace
YES


Are the A/C thermo (X-15) and heater & A/C (X-11)
and A/C compressor (X-14) relay OK?

Are the No. SBF-8 fuse (30A) and the No. EB-13
(10A) fuses OK
YES


Is the pressure switch (C-24) OK?
YES


Are the A/C switch (B-57) and the fan switch (B-13)
OK?
NO
YES


Is there continuity between the engine harness
connector terminal No.1 (E-3) and engine room harness
connector terminal No.2 (X-14)?

Disconnect the A/C compressor relay.

Turn the ignition switch "ON" (Engine is running)


A/C switch and fan control knob (fan switch "ON")
NO
Replace
NO
Defective switch or insufficient
refrigerant
NO
NO
Does the magnetic clutch
operate?
YES
Replace


Disconnect the magnetic clutch connector.

Is there battery voltage between the engine room harness
connector terminal No.1 (E-3) and ground?
Defective compressor
YESNO
Defective magnetic clutch

HEATER AND AIR CONDITIONING 1-91





Open circuit between the engine
harness connector terminal No.1 (E-3)
and engine room harness connector
terminal No.2 (X-14).
YES


Is there battery voltage between the engine room
harness connector terminal No.1 (X-14) and
ground?
YES


Disconnect the A/C thermo relay.
YES


Is there continuity between the ECM harness
connector terminal No.38 (C-56) and engine
room harness connector terminal No.4 (X-14)?
NO
Open circuit between the No. EB-13
fuse and engine room harness
connector terminal No.1 (X-14).
NO
Open circuit between the engine room
harness connector terminal No.1 (X-
15) and engine room harness
connector terminal No. 3 (X-14).
NO

Is there continuity between the engine room
harness connector terminal No.3 (X-14) and No.1
(X-15)?
YES


Is there continuity between the ECM harness
connector terminal No.30 (C-56) and engine
room harness connector terminal No.2 (X-15)? Open circuit between the engine room
harness connector terminal No.1 (X-
15) and engine room harness
connector terminal No. 3 (X-14).
NO
YES


Is there battery voltage between the engine room
harness connector terminal No.4 (X-15) and
ground?
Open circuit between the ECM
harness connector No. 38 (C-56) and
engine room harness connector
terminal No. 4 (X-14).
NO
YES


Is there continuity between the engine room
harness connector terminal No. 3 (X-15) and the
engine room harness connector terminal No. 1 (C-
24).
Open circuit between the No. EB-13
fuse and engine room harness
connector terminal No. 4 (X-15).
NO


Disconnect the ECM harness connector.


Disconnect the pressure switch?

1-92 HEATER AND AIR CONDITIONING




YES

Disconnect the condenser fan relay connector
condenser fan.
YES


Is there battery voltage between the engine
room harness connector terminal NO.3 (C-
24) and ground? Open circuit between the condenser
fan relay 4JH1TC No.4 (X-6) 4JA1L
No. 3 (X-13) and engine room harness
connector terminal No. 4 (X-14).
NO

Is there continuity between the relay terminal
4JH1TC No. 4 (X-6) 4JA1L No.3 (X-13)and
engine room harness connector terminal No.4
(C-24)?
YES


connect the A/C thermo relay connector.
Open circuit between the No. EB-13
fuse and engine room harness
connector terminal No. 3 (C-24).
NO
YES


Is there battery voltage between the engine
room harness connector terminal No.3 (C-55)
dd?
Open circuit between the engine room
harness connector terminal No. 2 (C-
55) and the engine room harness
connector terminal No. 2 (C-24).
NO
YES


Is there continuity between the engine room
harness connector terminal No.1 (C-55) and
ground (C-109) ? or (cooler only) the short
connector terminal No.3 (B-79) and ground (C-
109
)?
Open circuit between the No. EB-13
fuse and engine room harness
connector terminal No. 3 (C-55).
NO


Disconnect the electronic themostat.


Is there continuity between the engine room
harness connector terminal No. 2 (C-55) and the
engine room harness connector terminal No. 2
(C-24).
Open circuit between and engine room
harness connector terminal No. 3 (X-
15) and the engine room harness
connector terminal No. 1(C-24).
NO