2004 ISUZU TF SERIES fuel pressure

6C-14 ENGINE FUEL (C24SE)
Removal
CAUTION: When repair to the fuel system has been
completed, start engine and check the fuel system
for loose connection or leakage. For the fuel system
diagnosis, see Section “Driveability and Emission".
1. Disconnect battery ground cable.
2. Loosen slowly the fuel filler cap.
NOTE: To prevent spouting out fuel to change the
pressure in the fuel tank.
NOTE: Cover opening of the filler neck to prevent any
dust entering.
3. Jack up the vehicle.
4. Support underneath of the fuel tank with a lifter.
5. Remove the inner liner of the wheel house on rea
r
left side.
6. Remove fasten bolt to the filler neck from the
body.
7. Disconnect the quick connector (8) into the fuel
tube from the fuel pipe and the evapo tube from
evapo joint connector.
NOTE: Cover the quick connector to prevent any dus
t
entering and fuel leaking.
NOTE: Refer to “Fuel Tube/Quick Connector Fittings” in
this section when performing any repairs.
8. Remove fasten bolt (1) to the tank band and the
tank band (2).
9. Disconnect the pump and sender connector on the
fuel pump and remove the harness from weld clip
on the fuel tank.
10. Lower the fuel tank (6).
NOTE: When the fuel tank is lowered from the vehicle,
don’t scratch each hose and tube by around other pars.


Installation
1. Rise the fuel tank into position.
NOTE: Ensure hoses and tubes do not foul on othe
r
component.
2. Connect the pump and sender connector to the
fuel pump and install harness to into the plastic clip
welded to the top of the fuel tank..
NOTE: The connector must be certainly connected
against stopper.
Ensure tank band anchor mates with guide hole on
frame.
3. Install the tank band to fasten bolt.
Torque: 68 N




m (6.9kg




m/50 lb ft)
NOTE: The anchor of the tank band must be certainly
installed to guide hole on frame.
4. Connect the quick connector from the fuel tube to
the fuel pipe and the evapo tube from evapo join
t
connector.
NOTE: Pull off the left checker into the fuel pipe.
NOTE: Refer to “Fuel Tube/Quick Connector Fittings” in
this section when performing any repairs.
5. Install the filler neck to the body by bolt.
6. Install the inner liner of the wheel house on rea
r
side.
7. Remove lifter to support underneath of the fuel
tank.
8. Put back the vehicle.
9. Tigten the filler cap until at least three clicks are
heard.
10. Connect the battery ground cable.

6C-16 ENGINE FUEL (C24SE)
Fuel Filler Cap
General Description
A vacuum valve and pressure valve are built into the
fuel filler cap which adjusts the fuel pressure in the fuel
tank to prevent fuel tank damage.



RTW36CSH000401
Legend
(1) Pressure Valve
(2) Vacuum Valve
(3) Seal Ring

Inspection
The fuel filler cap must be inspected for seal condition.
The fuel filler cap must be replaced if found defective
CAUTION: A replacement fuel filler cap must be the
same as the original. The fuel filler cap valve was
designed primarily for this application and must be
replaced with the same type or decreased engine
performance may occur.

ENGINE DRIVEABILITY AND EMISSIONS 6E–1
ENGINE
CONTENTS
C24SE ENGINE DRIVEABILITY AND EMISSIONS
ABBREVIATIONS CHARTS ......................... 6E-6
ECM Circuit Diagram (1/2) ............................ 6E-11
ECM Circuit Diagram (2/2) ............................ 6E-12
GROUND POINT CHART - LHD G.EXP (1/4) 6E-13
GROUND POINT CHART - RHD G.EXP (1/4) 6E-17
LOCATION ................................................... 6E-21
CABLE HARNESS & CONNECTOR
LOCATION .............................................. 6E-23
CABLE HARNESS & CONNECTOR
LOCATION
LHD ................................... 6E-24
CABLE HARNESS & CONNECTOR
LOCATION
RHD ................................... 6E-25
CONNECTOR LIST ...................................... 6E-28
RELAY AND FUSE ....................................... 6E-30
RELAY AND FUSE BOX LOCATION
(LHD & RHD) ........................................... 6E-30
FUSE AND RELAY LOCATION (LHD & RHD) 6E-32
ECM WIRING DIAGRAM (1/9) ..................... 6E-33
ECM WIRING DIAGRAM (2/9) ..................... 6E-34
ECM WIRING DIAGRAM (3/9) ..................... 6E-35
ECM WIRING DIAGRAM (4/9) ..................... 6E-36
ECM WIRING DIAGRAM (5/9) ..................... 6E-37
ECM WIRING DIAGRAM (6/9) ..................... 6E-38
ECM WIRING DIAGRAM (7/9) ..................... 6E-39
ECM WIRING DIAGRAM (8/9) ..................... 6E-40
ECM WIRING DIAGRAM (9/9) ..................... 6E-41
ECM CONNECTOR PIN ASSIGNMENT &
OUTPUT SIGNAL .................................... 6E-42
GENERAL DESCRIPTION FOR ECM AND
SENSORS ............................................... 6E-48
Engine Control Module (ECM) ................... 6E-48
Manifold Absolute Pressure (MAP) Sensor 6E-48
Throttle Position Sensor (TPS) .................. 6E-49
Idle Air Control (IAC) Valve ....................... 6E-49
Crankshaft Position (CKP) Sensor ............ 6E-50
Knock Sensor (KS) .................................... 6E-50
Engine Coolant Temperature (ECT) Sensor 6E-50
Intake Air Temperature (IAT) Sensor ........ 6E-51
Vehicle Speed Sensor (VSS) .................... 6E-51
Heated Ox ygen (O
2) Sensor ..................... 6E-51
GENERAL DESCRIPTION FOR FUEL
METERING .............................................. 6E-52Battery Voltage Correction Mode ............... 6E-52
Clear Flood Mode ...................................... 6E-52
Deceleration Fuel Cutoff (DFCO) Mode .... 6E-52
Engine Speed/ Vehicle Speed/ Fuel Disable
Mode ........................................................ 6E-52
Acceleration Mode ..................................... 6E-52
Fuel Cutoff Mode ....................................... 6E-52
Starting Mode ............................................ 6E-52
Run Mode .................................................. 6E-52
Fuel Metering System Components .......... 6E-53
Fuel Injector ............................................... 6E-53
Fuel Pressure Regulator ............................ 6E-53
Fuel Rail ..................................................... 6E-53
Fuel Pump Electrical Circuit ....................... 6E-53
Thottle Body Unit ....................................... 6E-53
GENERAL DESCRIPTION FOR ELECTRIC
IGNITION SYSTEM ................................. 6E-54
Spark Plug ................................................. 6E-54
GENERAL DESCRIPTION FOR EVAPORATIVE
EMISSION SYSTEM ............................... 6E-57
EVAP Emission Control System Purpose .. 6E-57
EVAP Emission Control System Operation 6E-57
System Fault Detection .............................. 6E-57
POSITIVE CRANKCASE VENTILATION (PCV)
SYSTEM .................................................. 6E-59
Crankcase Ventilation System Purpose .... 6E-59
A/C CLUTCH DIAGNOSIS ........................ 6E-60
A/C Clutch Circuit Operation ...................... 6E-60
A/C Clutch Circuit Purpose ........................ 6E-60
A/C Request Signal ................................... 6E-60
ISUZU STRATEGY BASED DIAGNOSTICS 6E-61
Overview .................................................... 6E-61
STRATEGY BASED DIAGNOSTICS CHART 6E-61
Diagnostic Thought Process ...................... 6E-62
1. Verify the Complaint .............................. 6E-62
2. Perform Preliminary Checks .................. 6E-62
3. Check Bulletins and Troubleshooting Hints 6E-63
4. Perform Service Manual Diagnostic Checks 6E-63
5a and 5b. Perform Service Manual Diagnostic
Procedures .............................................. 6E-63
5c. Technician Self Diagnoses .................. 6E-63
5d. Intermittent Diagnosis .......................... 6E-64

6E–2 ENGINE DRIVEABILITY AND EMISSIONS
5e. Vehicle Operates as Designed ............ 6E-65
6. Re-examine the complaint ..................... 6E-66
7. Repair and Verify Fix ............................. 6E-66
GENERAL SERVICE INFORMATION .......... 6E-67
On-Board Diagnostic (OBD) ...................... 6E-68
On-Board Diagnostic Tests ....................... 6E-68
The Diagnostic Executive .......................... 6E-68
Diagnostic Information ............................... 6E-68
Check Engine Lamp .................................. 6E-68
Data Link Connector (DLC) ....................... 6E-68
Tech 2 Operating Flow Cart (Start Up) ...... 6E-70
TYPICAL SCAN DATA & DEFINITIONS
(ENGINE DATA) ......................................... 6E-72
TYPICAL SCAN DATA & DEFINITIONS
(O2 SENSOR DATA) .................................. 6E-74
MISCELLANEOUS TEST ............................. 6E-76
PLOTTING SNAPSHOT GRAPH ................. 6E-78
Plotting Graph Flow Chart (Plotting graph after
obtaining vehicle information) .................. 6E-79
Flow Chart for Snapshot Replay
(Plotting Graph) ....................................... 6E-80
SNAPSHOT DISPLAY WITH TIS2000 ......... 6E-81
ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK
6E-98
Circuit Description ......................................... 6E-90
Diagnostic Aids ............................................. 6E-90
Test Description ............................................ 6E-90
ON-BOARD DIAGNOSTIC (OBD) SYSTEM
CHECK .................................................... 6E-91
NO CHECK ENGINE LAMP (MIL) ................ 6E-94
Circuit Description ..................................... 6E-94
Diagnostic Aids .......................................... 6E-94
No Check Engine Lamp (MIL) ................... 6E-94
CHECK ENGINE LAMP (MIL) “ON” STEADY 6E-96
Circuit description ...................................... 6E-96
Diagnostic Aids .......................................... 6E-96
Check Engine Lamp (MIL) “ON” Steady .... 6E-96
FUEL METERING SYSTEM CHECK ........... 6E-98
FUEL INJECTOR COIL TEST PROCEDURE
AND FUEL INJECTOR BALANCE TEST
PROCEDURE ............................................. 6E-98
Test Description ......................................... 6E-98
Injector Coil Test Procedure (Steps 1-6)
and Injector Balance Test Procedure
(Steps 7-11) ............................................. 6E-99
Injector Coil Test Procedure (Steps 1-6)
and Injector Balance Test Procedure
(Steps 7-11) ............................................. 6E-100
FUEL SYSTEM ELECTRICAL TEST ........... 6E-103
Circuit Description ..................................... 6E-103
Diagnostic Aids .......................................... 6E-104Fuel Pressure Relief Procedure ................. 6E-104
Fuel Pressure Gauge Installation .............. 6E-104
Fuel System Electrical Test ....................... 6E-104
FUEL SYSTEM DIAGNOSIS ........................ 6E-108
Circuit Description ...................................... 6E-108
Test Description ......................................... 6E-108
Fuel Pressure Relief Procedure ................. 6E-109
Fuel Pressure Gauge Installation .............. 6E-109
Fuel System Diagnosis .............................. 6E-110
ECM DIAGNOSTIC TROUBLE CODES (DTC) 6E-113
DIAGNOSTIC TROUBLE CODE (DTC) P0107
MANIFOLD ABSOLUTE PRESSURE
CIRCUIT LOW INPUT ................................ 6E-119
Circuit Description ...................................... 6E-119
Diagnostic Aids .......................................... 6E-119
Diagnostic Trouble Code (DTC) P0107
Manifold Absolute Pressure Circuit Low
Input ......................................................... 6E-120
DIAGNOSTIC TROUBLE CODE (DTC) P0108
MANIFOLD ABSOLUTE PRESSURE
CIRCUIT HIGH INPUT ............................... 6E-123
Circuit Description ...................................... 6E-123
Diagnostic Aids .......................................... 6E-124
Diagnostic Trouble Code (DTC) P0108
Manifold Absolute Pressure Circuit High
Input ......................................................... 6E-124
DIAGNOSTIC TROUBLE CODE (DTC) P0112
INTAKE AIR TEMPERATURE SENSOR LOW
INPUT ......................................................... 6E-127
Circuit Description ...................................... 6E-127
Diagnostic Aids .......................................... 6E-127
Diagnostic Trouble Code (DTC) P0112
Intake Air Temperature Sensor Low Input 6E-128
DIAGNOSTIC TROUBLE CODE (DTC) P0113
INTAKE AIR TEMPERATURE SENSOR HIGH
INPUT ......................................................... 6E-131
Circuit Description ...................................... 6E-131
Diagnostic Aids .......................................... 6E-131
Diagnostic Trouble Code (DTC) P0113
Intake Air Temperature Sensor High Input 6E-132
DIAGNOSTIC TROUBLE CODE (DTC) P0117
ENGINE COOLANT TEMPERATURE
SENSOR LOW INPUT ................................ 6E-136
Circuit Description ...................................... 6E-136
Diagnostic Aids .......................................... 6E-136
Diagnostic Trouble Code (DTC) P0117
Engine Coolant Temperature Sensor Low
Input ......................................................... 6E-137
DIAGNOSTIC TROUBLE CODE (DTC) P0118
ENGINE COOLANT TEMPERATURE
SENSOR HIGH INPUT ............................... 6E-139
Circuit Description ...................................... 6E-139

ENGINE DRIVEABILITY AND EMISSIONS 6E–5
ENGINE CRANKS BUT WILL NOT RUN ..... 6E-233
HARD START SYMPTOM ............................ 6E-236
ROUGH, UNSTABLE, OR INCORRECT IDLE,
STALLING SYMPTOM ............................... 6E-239
SURGES AND/OR CHUGS SYMPTOM ...... 6E-242
HESITATION, SAG, STUMBLE SYMPTOM 6E-245
CUTS OUT, MISSES SYMPTOM ................. 6E-248
LACK OF POWER, SLUGGISH OR SPONGY
SYMPTOM ................................................. 6E-251
DETONATION/SPARK KNOCK SYMPTOM 6E-254
POOR FUEL ECONOMY SYMPTOM .......... 6E-256
EXCESSIVE EXHAUST EMISSIONS OR
ODORS SYMPTOM ................................... 6E-258
DIESELING, RUN-ON SYMPTOM ............... 6E-261
BACKFIRE SYMPTOM ................................. 6E-262
ON-VEHICLE SERVICE PROCEDURE ....... 6E-264
ENGINE CONTROL MODULE (ECM) .......... 6E-264
CRANKSHAFT POSITION (CKP) SENSOR 6E-264
ENGINE COOLANT TEMPERATURE (ECT)
SENSOR .................................................... 6E-265
INTAKE AIR TEMPERATURE (IAT) SENSOR 6E-265
MANIFOLD ABSOLUTE PRESSURE (MAP)
SENSOR .................................................... 6E-266
THROTTLE POSITION SENSOR (TPS) ...... 6E-266
IDLE AIR CONTROL (IAC) VALVE .............. 6E-267
KNOCK SENSOR ......................................... 6E-268
POWER STEERING PRESSURE (PSP)
SWITCH ..................................................... 6E-268
HEATED OXYGEN SENSOR (HO2S) ......... 6E-269
EVAP CANISTER PURGE VALVE SOLENOID 6E-269
FUEL PRESSURE RELIEF .......................... 6E-270
FUEL RAIL ASSEMBLY ............................... 6E-270
FUEL INJECTOR .......................................... 6E-271
FUEL PRESSURE REGULATOR ................ 6E-273
IGNITION COIL ............................................ 6E-275
SPARK PLUGS ............................................ 6E-275
SPARK PLUG CABLES ................................ 6E-277
EMISSION CONTROL ; CO ADJUSTER (W/O
CATALYSTIC CONVERTER) .................. 6E-277
SPECIAL SERVICE TOOLS ......................... 6E-279

6E–6 ENGINE DRIVEABILITY AND EMISSIONS
ABBREVIATIONS CHARTS
A bbreviations A ppellation
A/C Air Conditioner
A/T Automatic Transmission
ACC Accessory
BLK Black
BLU Blue
BRN Brown
CEL Check Engine Lamp
CKP Crankshaft Position
DLC Data Link Connector
DTC Diagnostic Trouble Code
DVM Digital Volt Meter
ECM Engine Control Module
ECT Engine Coolant Temperature
EEPROM Electrically Erasable & Programmable Read Only Memory
EVAP Evaporative Emission
EVRV Electric Vacuum Regulating Valve
EXH Exhaust
FT Fuel Temperature
GND Ground
GRY Gray
HOS2 Heated Ox ygen Sensor
IAC Idel Air Control
IAT Intake Air Temperature
IG Ignition
ITP Intake Throttle Position
KS Knock Sensor
M/T Manual Transmission
MAP Manifold Absolute Pressure
MIL Malfunction Indicator Lamp
OBD On-Board Diagnostic
ORN Orange
OT Oil Temperature
PNK Pink
RED Red
SW Switch
TB Throttle Body
TEMP Temperature
TP Throttle Posi tion
VCC Voltage Constant Control
VSS Vehicle Speed Sensor
WHT Whi te
Y EL Yellow

6E–10 ENGINE DRIVEABILITY AND EMISSIONS
(1) Canister(1)
(2)Fuel Tank
Fuel Pump
2 1
(1)
(2)Vehicle Speed Sensor (VSS)
Transmission Assembly
12
(1)
(2)Power Steering Pressure Switch
Power Steering Oil Pump Assembly
12

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