2004 ISUZU TF SERIES fuel pump

ENGINE DRIVEABILITY AND EMISSIONS 6E–29
No. Connector face No. Connector face
E-84
Knock sensorP-1
Silver Battery (+)
E-85
MAP sensorP-2
Silver Relay & Fuse box
F-2
White Fuel pump & sensorP-5
Silver Battery (-)
H-4
White Engine room ~ MissionP-6
Silver Body earth (Ground)
H-6
White Engine room ~ INSTP-10
Silver Engine ground
H-7
White Engine room ~ INSTX-2
Black Relay; Fuel pump
H-9
Blue Engine room ~ ChassisX-11
Black Relay; Heater
H-18
White Engine room ~ INSTX-14
Black Relay; A/C Compressor
H-31
Engine room ~ Mission
H-34
Engine ~ Engine room

ENGINE DRIVEABILITY AND EMISSIONS 6E–31
RELAY A ND FUSE BOX LOCATION (LHD & RHD)
RELAY & FUSE BOX
RELAY
No. Relay Name
X-1 RELAY; TAIL LIGHT
X-2 RELAY; FUEL PUMP
X-3 RELAY; HORN
X-4 RELAY; DIMMER
X-5 RELAY; FRT FOG
LIGHT (LHD only)
X-6 RELAY; STARTER
X-7 RELAY; COND, FAN
X-8—
X-9—
X-10—
X-11 RELAY; HEATER
X-12 RELAY; HEAD LIGHT
X-13—
X-14 RELAY; A/C COMP
X-15 RELAY; THERMO
FUSE
NO. Fuse Name
EB-1 15A ECM
EB-2—
EB-3 15A FRT FOG
EB-4 15A ACG (S)
EB-5 10A ILLUMI
EB-6 10A TAIL
EB-7 10A H/LIGHT-RH
10A H/LIGHT-RH-LOW
EB-8 10A H/LIGHT-LH
10A H/LIGHT-LH-LOW
(LHD only)
EB-9 20A FUEL PUMP
EB-10 10A O
2 SENSOR
EB-11 10A H/LIGHT-RH-
HIGH (LHD only)
EB-12 10A H/LIGHT-LH-
HIGH (LHD only)
EB-13 10A A/C
EB-14—
EB-15 10A HORN
EB-16 10A HAZARD
SLOW BLOW FUSE
NO. Slow Blow Fuse Name FUSE NO. Slow Blow Fuse Name
SBF-1 100A MAIN SBF-6—
SBF-2—SBF-7—
SBF-3—SBF-8 30A BLOWER
SBF-4 20A COND, FAN SBF-9 50A IG 2
SBF-5 40A IG 1

6E–44 ENGINE DRIVEABILITY AND EMISSIONS
Connector J2 Port: View Looking Into ECM Case
1
1716
32
PIN32
PIN1 PIN17
PIN16
Pin
No. B/
Box
No.Pin FunctionWire
ColorSignal or Continuity
ECM
ConnectionTester Position
Key SW
OffKey SW
OnEngine
IdleEngine
2000rpmRange (+) (-)
J2-1 J2-1 Inta ke Air Temp. (IAT)
Sensor GroundGRN Continuity
with
ground- - - Disconnect
J2-1 GND
J2-2 J2-2 Batte ry Powe r Supply RED/
WH T10-14V Co nnect DC V J2-2 GND
J2-3 J2-3 Ignitio n Powe r Supply BLU/
YELLess than
1V10-14V Connect DC V J2-3 GND
J2-4 J2-4 To Da ta Link
Conne ctor No. 6BLU - - - - - - - -
J2-5 J2-5 No Connection - - - - - - - - -
J2-6 J2-6 Oxy ge n Se nsor
(Ground)PNK Continuity
with
ground- - - Connect
J2-6 GND
J2-7 J2-7 No Connection - - - - - - - - -
J2-8 J2-8 No Connection - - - - - - - - -
J2-9 J2-9 No Connection - - - - - - - - -
J2-10 J2-10 CO Adjust Signa l
(W/O Cata ly stic
Converter)YEL - - - - - - - -
J2-11 J2-11 Fuel Pump Re la y GRN/
WH T10-14V
While relay
is activated;
10-14V
R elay is no t
activated;
Less than
1V10-14V Connect DC V J2-11 GND
J2-12 J2-12 No Connection - - - - - - - - -
J2-13 J2-13 A/C Compre sso r
RelayGRY/
REDLess than
1VA/C comp. is operated: Less than 1V
A/C comp. is not operated: 10-14VCo nnect DC V J2-13 GND
J2-14 J2-14 No Connection - - - - - - - - -
J2-15 J2-15 No Connection - - - - - - - - -
J2-16 J2-16 No Connection - - - - - - - - -
J2-17 J2-17 CO Adjust (W/O
Cata ly stic Conv erter)RED - - - - - - - -
J2-18 J2-18 Batte ry Powe r Supply RED/
WH T10-14V Co nnect DC V J2-18 GND
J2-19 J2-19 No Connection - - - - - - - - -
J2-20 J2-20 Pow er Ste ering
Pressure SwitchGRN/
YELLess than
1V
Pressure switch is turned on: Less than 1V
Pressure switch is turned off: 10-14VCo nnect DC V J2-20 GND
J2-21 J2-21 Oxygen Sensor BLU Less than
1VApprox .
0.4VWave form D or 0.1 -
0.9V Co nnect DC V J2-21 J2-6
J2-22 J2-22 Inta ke Air Temp. (IAT)
Sensor (Signa l)YEL/
GRNLess than
1V
20
: Approx. 2.9V / 40
: Approx . 1.8V V
/ 60
: Approx. 1.1V / 80
: Approx . 0.6VCo nnect DC V J2-22 33

6E–48 ENGINE DRIVEABILITY AND EMISSIONS
GENERAL DESCRIPTION FOR ECM AND
SENSORS
Engine Control Module (ECM)
The engine control module (ECM) is located on the
intake manifold. The ECM controls the following.
Fuel metering system
Ignition timing
On-board diagnostics for electrical functions.
The ECM constantly observes the information from vari-
ous sensors. The ECM controls the systems that affect
vehicle performance. And it performs the diagnostic
function of the system.
The function can recognize operational problems, and
warn to the driver through the check engine lamp, and
store diagnostic trouble code (DTC). DTCs identify the
problem areas to aid the technician in marking repairs.
The input / output devices in the ECM include analog to
digital converts, signal buffers, counters and drivers.
The ECM controls most components with electronic
switches which complete a ground circuit when turned
on.
Inputs (Operating condition read):
Battery voltage
Electrical ignition
Ex haust oxygen content
Intake manifold pressure
Intake air temperature
Engine coolant temperature
Crankshaft positionKnock signal
Throttle position
Vehicle speed
Power steering pressure
Air conditioning request on or off
Outputs (Systems controlled):
Ignition control
Fuel control
Idle air control
Fuel pump
EVAP canister purge
Air conditioning
Diagnostics functions
Manifold Absolute Pressure (MAP) Sensor
The MAP sensor is a strain gage. A pressure strains the
resistance on the silicon base. At that time the
resistance value changes. And it changes voltage. In
other words it measures a pressure value. It is installed
to the intake manifold. Output voltage of the MAP
sensor is low as pressure is low. (1) J1 Port
(2) J2 Port
12
C h arac teris tic of MA P S ens or -R ef erenc e-
0 0.51 1.52 2.53 3.54 4.55
15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105
Mani fold A bs olute P res s ure (K P a) (T ec h2 Reading)
Output Voltage (V)

6E–52 ENGINE DRIVEABILITY AND EMISSIONS
GENERAL DESCRIPTION FOR FUEL
METERING
The fuel metering system starts with the fuel in the fuel
tank. An electric fuel pump, located in the fuel tank,
pumps fuel to the fuel rail through an in-line fuel filter.
The pump is designed to provide fuel at a pressure
above the pressure needed by the injectors.
A fuel pressure regulator in the fuel rail keeps fuel
available to the fuel injectors at a constant pressure.
A return line delivers unused fuel back to the fuel tank.
The basic function of the air/fuel metering system is to
control the air/fuel delivery to the engine. Fuel is
delivered to the engine by individual fuel injectors
mounted in the intake manifold.
The main control sensor is the heated ox ygen sensor
located in the ex haust system. The heated ox ygen
sensor reports to the ECM how much oxygen is in the
ex haust gas. The ECM changes the air/fuel ratio to the
engine by controlling the amount of time that fuel
injector is “On”.
The best mix ture to minimize exhaust emissions is 14.7
parts of air to 1 part of gasoline by weight, which allows
the catalytic converter to operate most efficiently.
Because of the constant measuring and adjusting of the
air/fuel ratio, the fuel injection system is called a “closed
loop” system.
The ECM monitors signals from several sensors in
order to determine the fuel needs of the engine. Fuel is
delivered under one of several conditions called “mode”.
All modes are controlled by the ECM.
Battery Voltage Correction Mode
When battery voltage is low, the ECM will compensate
for the weak spark by increasing the following:
The amount of fuel delivered.
The idle RPM.
Clear Flood Mode
Clear a flooded engine by pushing the accelerator pedal
down all the way. The ECM then de-energizes the fuel
injectors. The ECM holds the fuel injectors de-energized
as long as the throttle remains above 75% and the
engine speed is below 800 RPM. If the throttle position
becomes less than 75%, the ECM again begins to pulse
the injectors ON and OFF, allowing fuel into the
cylinders.
Deceleration Fuel Cutoff (DFCO) Mode
The ECM reduces the amount of fuel injected when it
detects a decrease in the throttle position and the air
flow. When deceleration is very fast, the ECM may cut
off fuel completely. Until enable conditions meet the
engine revolution less 1000 rpm or manifold absolute
pressure less than 10 kPa.
Engine Speed/ Vehicle Speed/ Fuel Disable
Mode
The ECM monitors engine speed. It turns off the fuel
injectors when the engine speed increases above 6000
RPM. The fuel injectors are turned back on when
engine speed decreases below 3500 RPM.
Acceleration Mode
The ECM provides ex tra fuel when it detects a rapid
increase in the throttle position and the air flow.
Fuel Cutoff Mode
No fuel is delivered by the fuel injectors when the
ignition is OFF. This prevents engine run-on. In addition,
the ECM suspends fuel delivery if no reference pulses
are detected (engine not running) to prevent engine
flooding.
Starting Mode
When the ignition is first turned ON, the ECM energizes
the fuel pump relay for two seconds to allow the fuel
pump to build up pressure. The ECM then checks the
engine coolant temperature (ECT) sensor and the
throttle position sensor to determine the proper air/fuel
ratio for starting.
The ECM controls the amount of fuel delivered in the
starting mode by adjusting how long the fuel injectors
are energized by pulsing the injectors for very short
times.
Run Mode
The run mode has the following two conditions:
Open loop
Closed loop
When the engine is first started, the system is in “open
loop” operation. In “Open Loop,” the ECM ignores the
signal from the heated oxygen sensor (HO2S). It
calculates the air/fuel ratio based on inputs from the TP,
ECT, and MAP sensors.
The system remains in “Open Loop” until the following
conditions are met:
The HO2S has a varying voltage output showing that
it is hot enough to operate properly (this depends on
temperature).
The ECT has reached a specified temperature.
A specific amount of time has elapsed since starting
the engine.
Engine speed has been greater than a specified RPM
since start-up.
The specific values for the above conditions vary with
different engines and are stored in the programmable
read only memory (PROM). When these conditions are
met, the system enters “closed loop” operation. In
“closed loop,” the ECM calculates the air/fuel ratio
(injector on-time) based on the signal from the HO2S.
This allows the air/fuel ratio to stay very close to 14.7:1.

ENGINE DRIVEABILITY AND EMISSIONS 6E–53
Fuel Metering System Components
The fuel metering system is made up of the following
parts.
Fuel injector
Throttle body
Fuel rail
Fuel pressure regulator
ECM
Crankshaft position (CKP) sensor
Idle air control (IAC) valve
Fuel pump
Fuel Injector
The group fuel injection fuel injector is a solenoid
operated device controlled by the ECM. The ECM
energizes the solenoid, which opens a valve to allow
fuel delivery.
The fuel is injected under pressure in a conical spray
pattern at the opening of the intake valve. Ex cess fuel
not used by the injectors passes through the fuel
pressure regulator before being returned to the fuel
tank.
Fuel Pressure Regulator
The fuel pressure regulator is a diaphragm-operated
relief valve mounted on the fuel rail with fuel pump
pressure on one side and manifold pressure on the
other side. The fuel pressure regulator maintains the
fuel pressure available to the injector at three times
barometric pressure adjusted for engine load. It may be
serviced separately.
If the pressure is too low or poor performance, DTC
P0131 or P1171 will be the result. If the pressure is too
high, DTC P0132 or P1167 will be the result. Refer to
Fuel System Diagnosis for information on diagnosing
fuel pressure conditions.
Fuel Rail
The fuel rail is mounted to the top of the engine and
distributes fuel to the individual injectors. Fuel is
delivered to the fuel inlet tube of the fuel rail by the fuel
lines. The fuel goes through the fuel rail to the fuel
pressure regulator. The fuel pressure regulator
maintains a constant fuel pressure at the injectors.
Remaining fuel is then returned to the fuel tank.
Fuel Pump Electrical Circuit
When the key is first turned ON, the ECM energizes the
fuel pump relay for two seconds to build up the fuel
pressure quickly. If the engine is not started within two
seconds, the ECM shuts the fuel pump off and waits
until the engine is cranked. When the engine is cranked
and the 58X crankshaft position signal has been
detected by the ECM, the ECM supplies 12 volts to the
fuel pump relay to energize the electric in-tank fuel
pump.
An inoperative fuel pump will cause a “no-start”
condition. A fuel pump which does not provide enoughpressure will result in poor performance.
Thottle Body Unit
The throttle body has a throttle plate to control the
amount of air delivered to the engine. The Thottle
position sensor and IAC valve are also mounted on the
throttle body.
Vacuum ports located behind the throttle plate provide
the vacuum signals needed by various components.
Engine coolant is directed through a coolant cavity in
the throttle body to warm the throttle valve and to
prevent icing.

ENGINE DRIVEABILITY AND EMISSIONS 6E–71
F0: Diagnostic Trouble Code
The purpose of the “Diagnostic Trouble Codes” mod e i s
to display stored trouble code in the ECM.
When “Clear DTC Information” is selected, a “Clear
DTC Information”, warning screen appears.
This screen informs you that by cleaning DTC's “all
stored DTC information in the ECM will be erased”.
After clearing codes, confirm system operation by test
driving the vehicle.
Use the “DTC Information” mode to search for a specific
type of stored DTC information.
History
This selection will display only DTCs that are stored in
the ECM's history memory. It will not display Type B
DTCs that have not requested the MIL (“Check EngineLamp”). It will display all type A and B DTCs that
requested the MIL and have failed within the last 40
warm-up cycles. In addition, it will display all type C and
D DTCs that have failed within the last 40 warm-up
cycles.
MIL SVC or Message Request
This selection will display only DTCs that are requesting
the MIL. Type C and Type D DTCs cannot be displayed
using the MIL. Type C and D DTCs cannot be displayed
using this option.
This selection will report type B DTCs only after the MIL
has been requested.
Last Test Failed
This selection will display only DTCs that have failed the
last time the test run. The last test may have run during
a previous ignition cycle of a type A or type B DTC is
displayed. For type C and type D DTCs, the last failure
must have occurred during the current ignition cycle to
appear as last test fail.
Test Failed Since Code Cleared
The selection will display all active and history DTCs
that have reported a test failure since the last time
DTCs were cleared. DTCs that last failed more that 40
warm-up cycles before this option is selected will not be
displayed.
No Run Since Code Cleared
This selection will display up to DTCs that have not run
since the DTCs were last cleared. Since any displayed
DTCs have not run, their condition (passing or failing) is
unknown.
Failed This Ignition
This selection will display all DTCs that have failed
during the present ignition cycle.
F1: Data Display
The purpose of the “Data Display” mode is to
continuously monitor data parameters.
The current actual values of all important sensors and
signals in the system are display through F1 mode.
See the “Typical Scan Data” section.
F2: Snapshot
“Snapshot” allows you to focus on making the condition
occur, rather than trying to view all of the data in
anticipation of the fault.
The snapshot will collect parameter information around
a trigger point that you select.
F3: Miscellaneous Test:
The purpose of “Miscellaneous Test” mode is to check
for correct operation of electronic system actuators.
F0: Diagnostic Trouble Code
F0: Read DTC Infor By Priority
F1: Clear DTC Information
F2: DTC Information
F0: History
F1: MIL SVS or Message Requested
F2: Last Test Failed
F3: Test Failed Since Code Cleared
F4: Not Run Since Code Cleared
F5: Failed This Ignition
F1: Data Display
F0: Engine Data
F1: O2 Sensor Data
F2: Snapshot
F3: Miscellaneous Test
F0: Lamps
F0: Malfunction Indicator Lamps
F1: Relays
F0: Fuel Pump Relay
F1: A/C Clutch Relay
F2: EVAP
F0: Purge Solenoid
F3: IAC System
F0: IAC Control
F1: IAC Reset
F4: Injector Balance Test

ENGINE DRIVEABILITY AND EMISSIONS 6E–73
20 A/C Reque st Ye s/NoOffOff This displays the air conditioner request signal. This
should display “On” whe n the air conditio ne r switch is
switche d o n.
21 EVAP Purge So le no id
(Evaporative
Emission)%0 - 100 - 10 This display s the duty signa l fro m the ECM to co ntrol the
ca nister purge so le no id v alve .
22 Fuel Pump On/OffOnOn This displays operating status for the fuel pump main
relay. This should display “On” when the key switch is
turned on and while engine is running.
23 Idle Air Contro l Ste ps20 - 3065 - 75 This displays the ECM commanded position of the idle air
control valve pintle. A larger number means that more air
is being commanded through the idle air passage.
24 Idle Speed Variation rpm-25 - 01125 - 1225 This displays variation of actual engine speed & desired
idle speed.
25 Vehicle Speed km/h or
mph00 This displays vehicle speed. The vehicle speed is
me asured by ECM from the v ehicle spe ed senso r.
26 Ignition Voltage V10.0 - 14.510.0 - 14.5 This displays the system voltage measured by the ECM
at ignition feed.
27 Reference Voltage V5.005.00
28 Ma lfunctio n Indicato r
La mpOn/OffOffOff This displays operating status for the Check Engine
La mp. This sho uld displa y “On” when the Check Engine
Lamp is turned on.
29Time From Start--This displays the engine time elapsed since the engine
was started. If the engine is stopped, engine run time will
be rese t to 00:00:00
Tech 2 ParameterUnitsIdle2000rpmDescription