Page 1291 of 6020

Engine Control System (4JH1) 6E-257
Checks Action
Electrical Connections or W iring Poor electrical connections, terminal tension or wiring problems cause most intermittent. To perform the following inspections:
• Inspect for poor mating of the connector halves, or terminals improperly seated in the
connector body.
• Inspect for improperly formed or damaged terminals. Test for poor terminal tension.
• Inspect for poor terminal to wire connections including terminals crimped over
insulation. This requires removing the terminal from the connector body.
• Inspect for corrosion/water intrusion. Pierced or damaged insulation can allow
moisture to enter the wiring. The conductor can corrode inside the insulation, with
little visible evidence. Look for swollen and stiff sections of wire in the suspect
circuits.
• Inspect for wires that are broken inside the insulation.
• Inspect the harness for pinched, cut or rubbed through wiring.
• Ensure that the wiring does not come in contact with hot exhaust components.
Control Module Power and Grounds
Component Power and Grounds Poor power or ground connections can cause widely varying symptoms.
• Test all control module power supply circuits. Many vehicles have multiple circuits
supplying power to the control module. Other components in the system may have
separate power supply circuits that may also need to be tested. Inspect connections
at the module/component connectors, fuses, and any intermediate connections
between the power source and the module/component. A test lamp or a DMM may
indicate that voltage is present, but neither tests the ability of the circuit to carry
sufficient current. Ensure that the circuit can carry the current necessary to operate
the component.
• Test all control module ground and system ground circuits. The control module may
have multiple ground circuits. Other components in the system may have separate
grounds that may also need to be tested. Inspect grounds for clean and tight
connections at the grounding point. Inspect the connections at the component and in
splice packs, where applicable. Ensure that the circuit can carry the current
necessary to operate the component.
Temperature Sensitivity • An intermittent condition may occur when a component/connection reaches normal
operating temperature. The condition may occur only when the
component/connection is cold, or only when the component/connection is hot.
• If the intermittent is related to heat, review the data for a relationship with the
following: - High ambient temperatures
- Under hood/engine generated heat
- Circuit generated heat due to a poor connection, or high electrical load
- Higher than normal load conditions, towing, etc.
• If the intermittent is related to cold, review the data for the following:
- Low ambient temperatures–In extremely low temperatures, ice may form in a connection or component. Test for water intrusion.
- The condition only occurs on a cold start.
- The condition goes away when the vehicle warms up.
• Information from the customer may help to determine if the trouble follows a pattern
that is temperature related.
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Page 1462 of 6020

6A-102 ENGINE MECHANICAL (4JK1/4JJ1)
Note:
Sort the removed bearings according to cylinders b
y
using tags.
LNW 21BSH004901
8. Remove the piston and connecting rod.
• Remove carbon on the upper side of the
cylinder block with a scraper.
• Pull out the piston and connecting rod towards
the cylinder head.
Note:
Be sure not to damage the oil jet and cylinder block
when pushing out the connecting rod.
9. Remove the connecting rod bearing.
Note:
Sort the bearings in the order of cylinders when reusing
them so that they are not confused with the bearings o
f
other cylinders.
Disassembly
1. Remove the piston ring.
• Use ring pliers to remove the piston ring.
Note:
Sort the piston rings in the same order as the cylinders
when reusing them so that they are not confused with
the pistons and piston rings of other cylinders.
LNW 21BSH005101
2. Remove the snap ring.
3. Remove the piston pin.
Note:
Sort the disassembled piston pins, pistons and
connecting rods together in the same order as the
cylinders.
LNW 21BSH005201
4. Remove the connecting rods from the piston.
5. Clean the piston. • Carefully clean carbon that is adhered to the
head of the piston and the groove of the piston
ring.
Note:
Do not use a wire brush to clean the piston because it
scratches the piston.
Visually inspect the piston for cracks, burns and othe
r
excessive wear, and replace it if there is an
y
abnormality.
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Page 1617 of 6020
ENGINE ELECTRICAL (4JK1/4JJ1) 6D-29
Pre-Heating System
Inspection and Repair
Make the necessary adjustments, repairs, and part
replacement if excessive wear of damage is discovered
during inspection.
Visual Check
Check the main fuses and glow indicator for damage.
Replace the part(s) if required.
Glow Relay
The glow relay is located in the relay box the engine
compartment.
Use an ohmmeter to measure the resistance between
terminals No.2 and No.3.
If the measured value is outside the specified range, the
glow relay must be replaced.
Glow Relay Resistance Ohms
94 - 114
825R300046
Glow Plug
Use a circuit tester to test the glow plugs for continuity.
Glow Plug Resistance (Reference) Ohms
Approximately 0.9
LNW 21KSH001401
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Page 1627 of 6020

6E-10 ENGINE CONTROL SYSTEM (4JK1/4JJ1)
Engine Controls Schematics
Power Distribution (1)
RTW76EXF003601
X-11
X-11 Heater
relay
1
2
Blower
motor Ignition
switchIgnition
switch Starter
relay
SBF1
Main
120A SBF2
ABS-1
40A SBF3
ABS-2
20A SBF5
IG1
40A SBF4
ECM
40A
SBF6
Blower
30A
EB-13
A/C
10A
2
BLU/
RED
3
BLU/
RED 3
BLU/
RED SBF8
Glow
60A
SBF7
Front
Fog
20A
SBF9
IG2
60A
EB-9
Fog
15A
or
Trailer
20AEB-10
Tail/Illumi
10A
or
Condenser
fan
20A EB-4
Engine
10A
EB-14
4WD
10A EB-15
Horn
10A EB-16
Hazard10A EB-1
ACG
(S)
10AEB-2
ECM
(B)
10AEB-3
F/Pump10A
EB-5 H/L HI(RH)10A Fuse
EB-6 H/L HI(LH)10A Fuse
EB-7 H/L LO(RH)10A Fuse
EB-8 H/L LO(LH)10A Fuse
P-6
Body
Generator P-5
8 BLK/
P-1
P-2
Battery
8
BLK 5WHTSrarter
Srarter
C-3
ELEC IG
10A
Fuse
E-92
0.5 WHT
0.3
BLK 3
WHT/
RED 5
WHT
0.3
BLK 5
RED/
BLU
5
RED
3
WHT/
BLK
30
BLK/
RED
30
BLK/
YEL
P-10
Engine
5
4 X-12
X-12
ECM
Fuel pump relay
ECM
ECM
main
relay
1
2 5
4
X-6
X-6
2
RED/
WHT
0.3
RED/
BLU Fuse/ relay box(Engine room)
2
RED
2
RED
0.5
RED
2
WHT
2
RED/
BLU 2
WHT
2
3 1
5
Lighting
switch Head
lamp
relay
C-36 C-36
RED
P-16
P-15
2nd
Battery
30
BLK/
YEL 30
BLK/
RED
P-10
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Page 1628 of 6020
ENGINE CONTROL SYSTEM (4JK1/4JJ1) 6E-11
Power Distribution (2)
RTW76EXF003701
C-108
5
WHT
3
WHT/
BLK
5
WHT
3
WHT/
BLK
3BLU
3BLK/RED
3
WHT/
BLK
3
BLK/
YEL 3
BLK/
WHT B-62
B-63
2
4
B-62
B-63 1
1
3
C-18
Rr
Def.
20A C-21
Door
lock
20A C-19
Meter
(+B)
10A C-15
Stop
lamp
15A C-22
Anti
theft
10A C-13
Audio
(+B)
15A
C-16
RR
Fog
10A C-17
Room
10A C-20
Power
window
30A Fuse/
relay box
(Cabin)
C-14
Meter
10A C-8
SRS
10AC-7
TCM
10A
or
15A C-9
Front
wiper
20A C-10
Back
up
15A C-6
Engine
10A
C-5
ABS/4WD
10AC-1
Starter
10AC-2
Trailer
10AC-3
ELEC IG
10A C-4
Turn
10AC-12
Cigar
lighter
&
ACC
Socket
20A C-11
Audio
10A
SBF9
IG2
60A Fuse/
relay
box
(Engine
room)
Starter relay
SBF5
IG1
40A
1
2
3 B-62 B1
B2
OFF
ACC
IG2ST
IG1 Ignition
switch
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Page 1629 of 6020

6E-12 ENGINE CONTROL SYSTEM (4JK1/4JJ1)
Starting and Charging System
RTW76EXF003801
EB-1
ACG(S)
10A
0.5
WHT
2
WHT
SBF1
Main
120A SBF5
IG1
40A Refer to
power
distribution Fuse/ relay
box(Engine room)
SBF9
IG2
60A
5
WHT 5
WHT
P-8 P-5
8 BLK/
RED
P-1
P-2
Battery
8
BLK
30
BLK/
YEL
P-10
P-16
P-15
2nd
Battery
30
BLK/
RED
30
BLK/
RED
30
BLK/
YEL
P-10 X-8
X-8
E-4
Generator H-1Starter
relay
1
1
H-4 E-92
8
2
4
E-4 E-17
2 B-23
3 B-24
8
3 X-7
X-7 Starter
cut
relay
1 3
45
Starter
P-4
1
B
S
SB
L
P-3 0.3
WHT/
BLU
5
WHT
5
WHT
0.5
WHT
Charge
lightIP
cluster
H-6
1
0.5
WHT/
BLU
0.5
WHT/
BLU H-49
1 C-108
3
WHT/
BLK
3
WHT/
BLK
3
BLK/
YEL
0.5
YEL 3
BLK/
WHT B-62
B-63
2
3
C-14
Meter
10A C-1
Starter
10A C-6
Engine
10A
0.5
WHT/
GRN
0.5
WHT/
GRN
0.5
RED/
WHT
0.5RED/WHT
0.5WHT/GRN
0.5
RED/
WHT
Starter switchsignal Ignition
switchsignal Glow relay
DRM
ECM Refer to
power
distribution
Fuse/relay
box(Cabin)
1
2
3 B-62 1 B-63
5 5 9 C-107
B-56
44
35 72
B1
B2
OFF
ACC
IG2
ST
IG1 Ignition
switch
Relay
control
4
0.3
BLK/
WHT
3
BLK/
YEL
0.3
BLK/
YEL
3
WHT
0.5YEL
Fuse/relay box(Engine room)3WHT/BLK
0.5
BLU/
YEL
H-4
A/T
M/T
C-36
E-10 0.5
BLK/
WHT
Inhibitor
switch 0.3
BLK 0.5
ORN/
BLU
0.5
BLK E-51
7
(4)
E-51
10
(1) C-58
( )...High output
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Page 1630 of 6020
ENGINE CONTROL SYSTEM (4JK1/4JJ1) 6E-13
ECM Power and Ground
RTW76EXF004501
X-12
X-12 ECM
main
relay
4
5
2 65
45 63 Ground
73
C-58 E-90
Ground
1
X-13
X-13 Fuel
pump
relay
0.5
ORN/
BLU 5
RED/
BLU
5
RED/
BLU
0.5 ORN/BLU
Fuel
pump 0.5
ORN/
BLK
0.5
BLK
C-109 Relay
control
Fuel
pump
resistor H-9
F-2 5
RED
0.5
BLU/
RED
0.5
BLU/
RED
0.5
BLU/
RED
2
RED/
BLU
EB-3
F/Pump
10A
SBF4
ECM
40A
EB-2
ECM
(B)
10A
Refer to
Power
distribution
TCM 0.5
YEL/
VIO
0.5
RED/
WHT
0.5
RED/
WHT
0.5
RED
0.5
RED 3
1
5
2
1
C-157
1 F-24
C-57
2 0.3
BLK
2
BLK
C-36 C-2E-10
Battery voltage
Battery voltage
(Back up) Fuse/
relay
box ECM
main
relay
control
4
H-49
1
52 C-58
ECM
54
73 EB-4
Engine
10A
Fuse (Engine
room)
0.5
BLK
0.3
BLKH-18
1
2
BLKB-82
Weld
splice 6
5
BLK
H-18
13
Ignition voltage
ECM
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ISUZU KB P190 2007
Page 1631 of 6020
6E-14 ENGINE CONTROL SYSTEM (4JK1/4JJ1)
DLC and CAN (Standard output)
RTW76EXF004601
7
6766 C-58
31
16
4 5 B-58 1
614 B-58
32 B-2356 B-68
C-19
Meter(+B)
10A
Fuse/
relay
box
(Cabin)
0.5
BLU
0.5
RED/
YEL
ICU
IP cluster
40.5
YEL
0.5
BLU 0.5
YEL
0.5
BLU
DLC
0.5
YEL
IP
cluster
W/O Immobilizer ICU
H-44
5
0.5
BLU
11
4 2
1 3 4
2
1 3
H-18
C-2
0.5
BLK
0.5
BLK
0.5
RED/
YEL
+B
2
BLK
B-82
Weld
splice 6
2BLK
13
3 B-56
ECM
Keyword 2000 0.5
BLK/
GRN
0.3
BLK/
GRN 0.5
BLU 0.5
YEL B-103
J/C 3
B-104
J/C 4
Diagnostic
switch
Diagnostic switch CAN
high CAN
low
Ground Ground 2
0.5
YEL
0.5
BLU 0.5
YELH-18
12
H-18(RHD)
H-48(LHD)
7(RHD)
12(LHD) CAN
low
CAN
high
CANlow
CAN
high
TCM C-94 (5)
EHCU C-67 (11)
SRS control unit B-31 (2)
0.5
VIO/
GRN
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