3.5L ENGINE DRIVEABILITY AND EMISSIONS 6E-1
ENGINE
3.5L ENGINE DRIVEABILITY AND EMISSIONS
CONTENTS
ABBREVIATION CHARTS ................................ 6E-5
COMPONENT LOCATOR ................................. 6E-6
ENGINE COMPONENT LOCATOR TABLE .. 6E-6
ECM CIRCUIT DIAGRAM ................................. 6E-10
GROUND POINT CHART G.EXP (LHD)
WITHOUT EUROPE, ISRAEL, TURKEY (1/4). 6E-13
GROUND POINT CHART G.EXP (LHD) (2/4) .. 6E-14
GROUND POINT CHART G.EXP (LHD) (3/4) .. 6E-15
GROUND POINT CHART G.EXP (LHD) (4/4) .. 6E-16
GROUND POINT CHART G.EXP (RHD) (1/4) . 6E-17
GROUND POINT CHART G.EXP (RHD) (2/4) . 6E-18
GROUND POINT CHART G.EXP (RHD) (3/4) . 6E-19
GROUND POINT CHART G.EXP (RHD) (4/4) . 6E-20
LOCATION ........................................................ 6E-21
CABLE HARNESS & CONNECTOR
LOCATION ....................................................... 6E-22
CONNECTOR LIST ........................................... 6E-27
RELAY AND FUSE ............................................ 6E-30
RELAY AND FUSE BOX LOCATION
(LHD&RHD) ................................................... 6E-30
RELAY AND FUSE BOX LOCATION
(LHD&RHD) ................................................... 6E-31
FUSE AND RELAY LOCATION
(LHD&RHD) ................................................... 6E-32
ECM WIRING DIAGRAM (1/10) ........................ 6E-33
ECM WIRING DIAGRAM (2/10) ........................ 6E-34
ECM WIRING DIAGRAM (3/10) ........................ 6E-35
ECM WIRING DIAGRAM (4/10) ........................ 6E-36
ECM WIRING DIAGRAM (5/10) ........................ 6E-37
ECM WIRING DIAGRAM (6/10) ........................ 6E-38
ECM WIRING DIAGRAM (7/10) ........................ 6E-39
ECM WIRING DIAGRAM (8/10) ........................ 6E-40
ECM WIRING DIAGRAM (9/10) ........................ 6E-41
ECM WIRING DIAGRAM (10/10) ...................... 6E-42
ECM CONNECTOR PIN ASSIGNMENT
& OUTPUT SIGNAL ......................................... 6E-43
GENERAL DESCRIPTION FOR ECM AND
SENSORS ........................................................ 6E-51
Mass Air Flow (MAF) Sensor & Intake Air
Temperature (IAT) Sensor ............................. 6E-52
Throttle Position Sensor (TPS)....................... 6E-52
Idle Air Control (IAC) Valve ............................ 6E-53
Camshaft Position (CMP) Sensor .................. 6E-53
Crankshaft Position (CKP) Sensor ................. 6E-54
Engine Coolant Temperature (ECT) Sensor .. 6E-54
Vehicle Speed Sensor (VSS) ......................... 6E-55
Heated Oxygen (O
2) Sensor........................... 6E-55
GENERAL DESCRIPTION FOR FUEL
METERING....................................................... 6E-56
GENERAL DESCRIPTION FOR ELECTRONIC
IGNITION SYSTEM IGNITION
COILS & CONTROL ......................................... 6E-58
GENERAL DESCRIPTION FOR EVAPORATIVE
EMISSION SYSTEM ........................................ 6E-61
GENERAL DESCRIPRION FOR EXHAUST
GAS RECIRCULATION (EGR) SYSTEM......... 6E-62
ISUZU STRATEGY BASED DIAGNOSTICS .... 6E-63
Diagnostic Thought Process .......................... 6E-64
1. Verify the Complaint ................................... 6E-64
2. Perform Preliminary Checks....................... 6E-64
3. Check Bulletins and Troubleshooting
Hints ........................................................... 6E-65
4. Perform Service Manual Diagnostic
Checks ....................................................... 6E-65
5a and 5b. Perform Service Manual
Diagnostic Procedures ............................... 6E-65
5c. Technician Self Diagnoses ....................... 6E-65
5d. Intermittent Diagnosis............................ 6E-66
Symptom Simulation Tests.......................... 6E-67
5e. Vehicle Operates as Designed ................. 6E-68
6. Re-Examine the Complaint ........................ 6E-68
7. Repair and Verify Fix .................................. 6E-68
GENERAL SERVICE INFORMATION .............. 6E-69
Aftermarket Electrical and Vacuum
Equipment ..................................................... 6E-69
Electrostatic Discharge Damage .................... 6E-69
6E-6 3.5L ENGINE DRIVEABILITY AND EMISSIONS
COMPONENT LOCATOR
ENGINE COMPONENT LOCATOR TABLE
Legend
(1) Engine Control Module (ECM)
(2) Throttle Position Sensor (TPS)
(3) Idle Air Control (IAC) Valve
(4) Battery
(5) Relay & Fuse Box
(6) Auto Cruise Actuator
(7) Mass Air Flow (MAF) & Intake Air Temperature
(IAT) Sensor Assembly
3.5L ENGINE DRIVEABILITY AND EMISSIONS 6E-29
No. Connector face No. Connector face
E-78
O2 sensor LH-Front P-1
SilverBattery (+)
E-79
Neutral start switch P-2
SilverRelay & Fuse box
F-2
White
Fuel pump & sensor P-5
SilverBattery (-)
H-4
White Engine ~ Engine room P-8
WhiteACG (L)
H-6
White
Engine room ~ INST P-10
SilverEngine ground
H-7
White
Engine room ~ INST X-2
BlackRelay ; Fuel pump
H-9
Blue
Engine room ~ Chassis X-13
BlackRelay ; ECM MAIN
H-18
White
Engine room ~ INST X-14
BlackRelay ; A/C Compressor
H-22
White
Engine ~ Engine room C X-15
BlackRelay ; Thermo
H-23
White Engine ~ Engine room B X-17
BlackDIODE
6E-30 3.5L ENGINE DRIVEABILITY AND EMISSIONS
RELAY AND FUSE
RELAY AND FUSE BOX LOCATION (LHD & RHD)
LHD
RHD
RTW48ALF000201 & 825R300008
3.5L ENGINE DRIVEABILITY AND EMISSIONS 6E-31
RELAY AND 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; FOG LIGHT
X-6 RELAY; STARTER
X-7 RELAY; COND, FAN
X-8 RELAY;
X-9 RELAY; HAZARD-RH
X-10 RELAY; HAZARD-LH
X-11 RELAY; HEATER
X-12 RELAY; HEAD LIGHT
X-13 RELAY; ECM MAIN
X-14 RELAY; A/C COMP
X-15 RELAY; THERMO
FUSE
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SLOW BLOW FUSE
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6E-32 3.5L ENGINE DRIVEABILITY AND EMISSIONS
FUSE & RELAY LOCATION (LHD & RHD)
RTW46EMF001001
FUSE
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0123 410
21,,+
5+
/
0123 410
21,,+
5+
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SLOW BLOW FUSE
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0123 410
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RELAY
Connector No. B-7 B-8 B-40
6VE1 REAR DEFOGGER POWER WINDOW ACC SOCKET
FUSE BOX
3.5L ENGINE DRIVEABILITY AND EMISSIONS 6E-55
Vehicle Speed Sensor (VSS)
The VSS is a magnet rotated by the transmission output
shaft. The VSS uses a hall element. It interacts with the
magnetic field treated by the rotating magnet. It outputs
pulse signal. The 12 volts operating supply from the
meter fuse.
Heated Oxygen (O2) Sensor
1
(1) Bank 1 Heated Oxygen Sensor (RH)
1
(1) Bank 2 Heated Oxygen Sensor (LH)
Each oxygen sensor consists of a 4-wire low
temperature activated zirconia oxygen analyzer elemen
t
with heater for operating temperature of 315C, and
there is one mounted on each exhaust pipe.
A constant 450millivolt is supplied by the ECM between
the two supply terminals, and oxygen concentration in
the exhaust gas is reported to the ECM as returned
signal voltage.
The oxygen present in the exhaust gas reacts with the
sensor to produce a voltage output. This voltage should
constantly fluctuate from approximately 100mV to
1000mV and the ECM calculates the pulse width
commanded for the injectors to produce the prope
r
combustion chamber mixture.
Low oxygen sensor output voltage is a lean mixture
which will result in a rich commanded to compensate.
High oxygen sensor output voltage is a rich mixture
which result in a lean commanded to compensate.
When the engine is first started the system is in "Open
Loop" operation. In "Open Loop", the ECM ignores the
signal from the oxygen sensors. When various
conditions (ECT, time from start, engine speed &
oxygen sensor output) are met, the system enters
"Closed Loop" operation. In "Closed Loop", the ECM
calculates the air fuel ratio based on the signal from the
oxygen sensors.
Heated oxygen sensors are used to minimize the
amount of time required for closed loop fuel control to
begin operation and allow accurate catalyst monitoring.
The oxygen sensor heater greatly decreases the
amount of time required for fuel control sensors to
become active.
Oxygen sensor heaters are required by catalyst monito
r
and sensors to maintain a sufficiently high temperature
which allows accurate exhaust oxygen content readings
further away from the engine.
6E-58 3.5L ENGINE DRIVEABILITY AND EMISSIONS
GENERAL DESCRIPTION FOR
ELECTRONIC IGNITION SYSTEM IGNITION
COILS & CONTROL
A separate coil-at-plug module is located at each spark
plug.
The coil-at-plug module is attached to the engine with
two screws. It is installed directly to the spark plug by an
electrical contact inside a rubber boot.
A three way connector provides 12 volts primary supply
from the ignition coil fuse, a ground switching trigge
r
line from the ECM, and ground.
The ignition control spark timing is the ECM's method o
f
controlling the spark advance and the ignition dwell.
The ignition control spark advance and the ignition dwell
are calculated by the ECM using the following inputs.
Engine speed
Crankshaft position (CKP) sensor
Camshaft position (CMP) sensor
Engine coolant temperature (ECT) sensor
Throttle position sensor
Park or neutral position switch
Vehicle speed sensor
ECM and ignition system supply voltage
Based on these sensor signal and engine load
information, the ECM sends 5V to each ignition coil
requiring ignition. This signal sets in the powe
r
transistor of the ignition coil to establish a grounding
circuit for the primary coil, applying battery voltage to
the primary coil.
At the ignition timing, the ECM stops sending the 5V
signal voltage. Under this condition the power transistor
of the ignition coil is set off to cut the battery voltage to
the primary coil, thereby causing a magnetic field
generated in the primary coil to collapse.
On this moment a line of magnetic force flows to the
secondary coil, and when this magnetic line crosses the
coil, high voltage induced by the secondary ignition
circuit to flow through the spark plug to the ground.
Ignition Control ECM Output
The ECM provides a zero volt (actually about 100 mV to
200 mV) or a 5-volt output signal to the ignition control
(IC) module. Each spark plug has its own primary and
secondary coil module ("coil-at-plug") located at the
spark plug itself. When the ignition coil receives the
5-volt signal from the ECM, it provides a ground path fo
r
the B+ supply to the primary side of the coil-at -plug
module. This energizes the primary coil and creates a
magnetic field in the coil-at-plug module. When the
ECM shuts off the 5-volt signal to the ignition control
module, the ground path for the primary coil is broken.
The magnetic field collapses and induces a high voltage
secondary impulse which fires the spark plug and
ignites the air/fuel mixture.
The circuit between the ECM and the ignition coil is
monitored for open circuits, shorts to voltage, and
shorts to ground. If the ECM detects one of these
events, it will set one of the following DTCs:
P0351: Ignition coil Fault on Cylinder #1
P0352: Ignition coil Fault on Cylinder #2
P0353: Ignition coil Fault on Cylinder #3
P0354: Ignition coil Fault on Cylinder #4
P0355: Ignition coil Fault on Cylinder #5
P0356: Ignition coil Fault on Cylinder #6
Spark Plug
Although worn or dirty spark plugs may give satisfactory
operation at idling speed, they frequency fail at highe
r
engine speeds. Faulty spark plugs may cause poor fuel
economy, power loss, loss of speed, hard starting and
generally poor engine performance. Follow the
scheduled maintenance service recommendations to
ensure satisfactory spark plug performance. Refer to
Maintenance and Lubrication.
Normal spark plug operation will result in brown to
grayish-tan deposits appearing on the insulator portion
of the spark plug. A small amount of red-brown, yellow,
and white powdery material may also be present on the
insulator tip around the center electrode. These
deposits are normal combustion by-products of fuels
and lubricating oils with additives. Some electrode wea
r
will also occur. Engines which are not running properly
are often referred to as “misfiring." This means the
ignition spark is not igniting the air/fuel mixture at the
proper time.
Spark plugs may also misfire due to fouling, excessive
gap, or a cracked or broken insulator. If misfiring
occurs before the recommended replacement interval,
locate and correct the cause.