engine coolant ISUZU TF SERIES 2004 Manual Online

6B-16 ENGINE COOLING (6VE1 3.5L)
Main Data and Specifications
General Specifications

M/T A/T
Cooling system Engine coolant forced circulation
Radiator Tube type corrugated
Heat radiation capacity 81.4 kw (70.004 kcal/h)
Heat radiation area 9.42m
(0.875ft
)
Radiator front area 0.28m
(0.026ft
)
Radiator dry weight 5.0kg (11.0lb) 5.2kg (11.4lb)
Radiator cap valve opening pressure 93.3
122.7kpa (13.5
17.8psi)
Engine coolant pump Centrifugal impeller type
Delivery 300 (317) or more
Pump speed 5000  50 rpm
Thermostat Wax pellet type with air hole
Valve opening temperature 74.5
78.5C (166.1
173.3F)
Engine coolant total capacity 12.3lit (13.0U.S qt) 12.2lit (12.9U.S qt)

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-2 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Visual/Physical Engine Compartment
Inspection ...................................................... 6E-74
Basic Knowledge of Tools Required............... 6E-71
Serial Data Communications .......................... 6E-71
On-Board Diagnostic (OBD) ........................... 6E-71
Comprehensive Component Monitor
Diagnostic Operation ..................................... 6E-71
The Diagnostic Executive ............................... 6E-72
Verifying Vehicle Repair ................................. 6E-73
Reading Flash Diagnostic Trouble Codes ...... 6E-73
Reading Diagnostic Trouble Codes Using
a Tech 2......................................................... 6E-73
On-Board Diagnosis (Self-Diagnosis)............. 6E-74
Diagnosis with Tech 2 .................................... 6E-75
TYPICAL SCAN DATA & DEFINITIONS
(ENGINE DATA) ............................................... 6E-79
TYPICAL SCAN DATA & DEFINITIONS
(O2 SENSOR DATA)........................................ 6E-81
MISCELLANEOUS TEST .................................. 6E-83
PLOTTING SNAPSHOT GRAPH ...................... 6E-85
Plotting Graph Flow Chart (Plotting graph
after obtaining vehicle information)................ 6E-86
Flow Chart for Snapshot Replay
(Plotting Graph) ............................................. 6E-87
SNAPSHOT DISPLAY WITH TIS2000.............. 6E-88
SERVICE PROGRAMMING SYSTEM (SPS).... 6E-91
HOW TO USE BREAKER BOX ........................ 6E-94
ON-BOARD DIAGNOSTIC (OBD) SYSTEM
CHECK ............................................................. 6E-97
NO CHECK ENGINE LAMP (MIL)..................... 6E-101
CHECK ENGINE LAMP (MIL) "ON" STEADY ... 6E-104
FUEL INJECTOR COIL TEST PROCEDURE
AND FUEL INJECTOR BALANCE
TEST PROCEDURE ......................................... 6E-106
FUEL SYSTEM ELECTRICAL TEST ................ 6E-111
FUEL SYSTEM DIAGNOSIS ............................. 6E-116
A/C SYSTEM CIRCUIT DIAGNOSIS ................ 6E-122
ECM DIAGNOSTIC TROUBLE CODES (DTC) 6E-130
MULTIPLE DTC SETS TROUBLESHOOTING
AIDS ................................................................. 6E-142
DTC P0101 (FLASH CODE 61) MASS
AIR FLOW SENSOR CIRCUIT
RANGE/PERFORMANCE ................................ 6E-146
DTC P0102 (FLASH CODE 61) MASS
AIR FLOW SENSOR CIRCUIT LOW INPUT ... 6E-149
DTC P0103 (FLASH CODE 61) MASS
AIR FLOW SENSOR CIRCUIT HIGH INPUT .. 6E-154
DTC P0112 (FLASH CODE 23) INTAKE AIR
TEMPERATURE (IAT) SENSOR LOW
INPUT ............................................................... 6E-158 DTC P0113 (FLASH CODE 23) INTAKE AIR
TEMPERATURE (IAT) SENSOR HIGH
INPUT ............................................................... 6E-163
DTC P0117 (FLASH CODE 14) ENGINE
COOLANT TEMPERATURER (ECT)
SENSOR LOW INPUT ..................................... 6E-168
DTC P0118 (FLASH CODE 14) ENGINE
COOLANT TEMPERATURER (ECT)
SENSOR HIGH INPUT..................................... 6E-173
DTC P0121 (FLASH CODE 21) THROTTLE
POSITION SENSOR (TPS) CIRCUIT
RANGE/PERFORMANCE ................................ 6E-179
DTC P0122 (FLASH CODE 21) THROTTLE
POSITION SENSOR (TPS) CIRCUIT
LOW INPUT ..................................................... 6E-183
DTC P0123 (FLASH CODE 21) THROTTLE
POSITION SENSOR (TPS) CIRCUIT
HIGH INPUT ..................................................... 6E-188
DTC P0131 (FLASH CODE 15) O2 SENSOR
CIRCUIT LOW VOLTAGE
(BANK 1 SENSOR 1) ....................................... 6E-193
DTC P0151 (FLASH CODE 15) O2 SENSOR
CIRCUIT LOW VOLTAGE
(BANK 2 SENSOR 1) ....................................... 6E-193
DTC P0132 (FLASH CODE 15) O2 SENSOR
CIRCUIT HIGH VOLTAGE
(BANK 1 SENSOR 1) ....................................... 6E-201
DTC P0152 (FLASH CODE 15) O2
SENSOR CIRCUIT HIGH VOLTAGE
(BANK 2 SENSOR 1) ....................................... 6E-201
DTC P0134 (FLASH CODE 15) O2 SENSOR
CIRCUIT NO ACTIVITY DETECTED
(BANK 1 SENSOR 1) ....................................... 6E-207
DTC P0154 (FLASH CODE 15) O2 SENSOR
CIRCUIT NO ACTIVITY
DETECTED (BANK 2 SENSOR 1) ................... 6E-207
DTC P0171 (FLASH CODE 44) O2 SENSOR
SYSTEM TOO LEAN (BANK 1) ....................... 6E-211
DTC P0174 (FLASH CODE 44) O2 SENSOR
SYSTEM TOO LEAN (BANK 2) ....................... 6E-211
DTC P0172 (FLASH CODE 45) O2 SENSOR
SYSTEM TOO RICH (BANK 1) ........................ 6E-216
DTC P0175 (FLASH CODE 45) O2 SENSOR
SYSTEM TOO RICH (BANK 2) ........................ 6E-216
DTC P1171 (FLASH CODE 44) FUEL
SUPPLY SYSTEM LEAN DURING POWER
ENRICHMENT (TYPE A) ................................. 6E-221
DTC P1172 (FLASH CODE 44) FUEL SUPPLY
SYSTEM LEAN DURING POWER
ENRICHMENT (TYPE B) ................................. 6E-221

3.5L ENGINE DRIVEABILITY AND EMISSIONS 6E-3
DTC P0201 (FLASH CODE 31) INJECTOR 1
CONTROL CIRCUIT ........................................ 6E-226
DTC P0202 (FLASH CODE 31) INJECTOR 2
CONTROL CIRCUIT ........................................ 6E-226
DTC P0203 (FLASH CODE 31) INJECTOR 3
CONTROL CIRCUIT ........................................ 6E-226
DTC P0204 (FLASH CODE 31) INJECTOR 4
CONTROL CIRCUIT ........................................ 6E-226
DTC P0205 (FLASH CODE 31) INJECTOR 5
CONTROL CIRCUIT ........................................ 6E-226
DTC P0206 (FLASH CODE 31) INJECTOR 6
CONTROL CIRCUIT ........................................ 6E-226
DTC P0336 (FLASH CODE 29) CRANKSHAFT
POSITION SENSOR CIRCUIT
RANGE/PERFORMANCE (58X) ...................... 6E-234
DTC P0337 (FLASH CODE 29) CRANKSHAFT
POSITION SENSOR CIRCUIT NO SIGNAL
(58X) ................................................................. 6E-234
DTC P0341 (FLASH CODE 41) CAMSHAFT
POSITION SENSOR CIRCUIT
RANGE/PERFORMANCE ............................... 6E-243
DTC P0342 (FLASH CODE 41) CAMSHAFT
POSITION SENSOR CIRCUIT NO SIGNAL .... 6E-243
DTC P0351 (FLASH CODE 42) IGNITION 1
CONTROL CIRCUIT ........................................ 6E-249
DTC P0352 (FLASH CODE 42) IGNITION 2
CONTROL CIRCUIT ........................................ 6E-249
DTC P0353 (FLASH CODE 42) IGNITION 3
CONTROL CIRCUIT ........................................ 6E-249
DTC P0354 (FLASH CODE 42) IGNITION 4
CONTROL CIRCUIT ........................................ 6E-249
DTC P0355 (FLASH CODE 42) IGNITION 5
CONTROL CIRCUIT ........................................ 6E-249
DTC P0356 (FLASH CODE 42) IGNITION 6
CONTROL CIRCUIT ........................................ 6E-249
DTC P0404 (FLASH CODE 32) EGR CIRCUIT
RANGE/PERFORMANCE (OPEN VALVE)....... 6E-258
DTC P1404 (FLASH CODE 32) EGR CIRCUIT
RANGE/PERFORMANCE (CLOSED VALVE) .. 6E-258
DTC P0405 (FLASH CODE 32) EGR
CIRCUIT LOW.................................................. 6E-263
DTC P0406 (FLASH CODE 32) EGR
CIRCUIT HIGH ................................................. 6E-268
DTC P0444 EVAP PURGE SOLENOID
VALVE CIRCUIT LOW VOLTAGE ................... 6E-274
DTC P0445 EVAP PURGE SOLENOID
VALVE CIRCUIT HIGH VOLTAGE .................. 6E-274
DTC P0500 (FLASH CODE 24) VEHICLE
SPEED SENSOR (VSS) CIRCUIT
RANGE/PERFORMANCE ................................ 6E-279 DTC P0562 (FLASH CODE 66) SYSTEM
VOLTAGE LOW .............................................. 6E-288
DTC P0563 (FLASH CODE 66) SYSTEM
VOLTAGE HIGH .............................................. 6E-321
DTC P0601 (FLASH CODE 51) ENGINE
CONTROL MODULE (ECM) MEMORY
CHECKSUM ..................................................... 6E-293
DTC P0602 PROGRAMMING ERROR............. 6E-295
DTC P1508 (FLASH CODE 22) IDLE AIR
CONTROL SYSTEM LOW/CLOSED ............... 6E-296
DTC P1509 (FLASH CODE 22) IDLE AIR
CONTROL SYSTEM HIGH/OPEN ................... 6E-296
DTC P1601 (FLASH CODE 65) CAN BUS
OFF .................................................................. 6E-304
DTC U2104 (FLASH CODE 67) CAN BUS
RESET COUNTER OVER-RUN ...................... 6E-310
DTC P1626 IMMOBILIZER NO SIGNAL ........... 6E-317
DTC P1631 IMMOBILIZER WRONG
SIGNAL ............................................................ 6E-323
DTC P1648 IMMOBILIZER WRONG
SECURITY CODE ENTERED .......................... 6E-325
DTC P1649 IMMOBILIZER FUNCTION NOT
PROGRAMMED ................................................ 6E-327
SYMPTOM DIAGNOSIS ................................... 6E-329
PRELIMINARY CHECKS .............................. 6E-329
VISUAL/PHYSICAL CHECK .......................... 6E-329
INTERMITTENT ............................................. 6E-329
ENGINE CRANKS BUT WILL NOT RUN ......... 6E-331
HARD START SYMPTOM ................................ 6E-334
ROUGH, UNSTABLE, OR INCORRECT
IDLE, STALLING SYMPTOM ........................... 6E-337
SURGES AND/OR CHUGS SYMPTOM ........... 6E-341
HESITATION, SAG, STUMBLE SYMPTOM ..... 6E-345
CUTS OUT, MISSES SYMPTOM ..................... 6E-347
LACK OF POWER, SLUGGISH OR SPONGY
SYMPTOM ....................................................... 6E-352
DETONATION/SPARK KNOCK SYMPTOM..... 6E-356
POOR FUEL ECONOMY SYMPTOM ............... 6E-359
EXCESSIVE EXHAUST EMISSIONS OR
ODORS SYMPTOM ......................................... 6E-362
DIESELING, RUN-ON SYMPTOM .................... 6E-365
BACKFIRE SYMPTOM ..................................... 6E-366
ON-VEHICLE SERVICE PROCEDURE ........... 6E-368
ENGINE CONTROL MODULE (ECM) .............. 6E-368
CRANKSHAFT POSITION (CKP) SENSOR ..... 6E-369
CAMSHAFT POSITION (CMP) SENSOR ......... 6E-369
ENGINE COOLANT TEMPERATURE (ECT)
SENSOR .......................................................... 6E-370
MASS AIR FLOW (MAF) SENSOR & INTAKE AIR
TEMPERATURE (IAT) SENSOR ...................... 6E-370

3.5L ENGINE DRIVEABILITY AND EMISSIONS 6E-5
ABBREVIATION CHARTS

Abbreviations Appellation
A/C Air conditioner
A/T Automatic transmission
ACC Accessory
BLK Black
BLU Blue
BRN Brown
CAN Controller Area Network
CEL Check engine lamp
CKP Crankshaft position
CMP Camshaft position
DLC Data link connector
DTC Diagnosis trouble code
DVM Digital voltage meter
ECM Engine control module
ECT Engine coolant temperature
EEPROM Electrically erasable & programmable read only memory
EGR Exhaust gas recalculation
GND Ground
GRY Gray
HO2S Heated Oxygen Sensor
IAT Intake air temperature
IAC Idle air control
IG Ignition
M/T Manual transmission
MAF Mass air flow
MIL Malfunction indicator lamp
OBD On-board diagnostic
ORN Orange
PNK Pink
PROM Programmable read only memory
RED Red
SW Switch
TPS Throttle position sensor
TCM Transmission control module
VCC Voltage Constant Control
VIO Violet
VSS Vehicle speed sensor
WHT White
WOT Wide open throttle
YEL Yellow

3.5L ENGINE DRIVEABILITY AND EMISSIONS 6E-7











Legend
(1) Injector #1 Cylinder
(2) Injector #3 Cylinder
(3) Injector #5 Cylinder
(4) EGR Valve
(5) Ignition Coil #1 Cylinder
(6) Ignition Coil #3 Cylinder
(7) Ignition Coil #5 Cylinder
(8) Engine Coolant Temperature (ECT) Sensor












Legend
(1) Injector #2 Cylinder
(2) Injector #4 Cylinder
(3) Injector #6 Cylinder
(4) Idle Air Control (IAC) Valve
(5) Throttle Position Sensor
(6) Ignition Coil #2 Cylinder
(7) Ignition Coil #4 Cylinder
(8) Ignition Coil #6 Cylinder
(9) Canister Purge Solenoid Valve

6E-44 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Signal or Continuity Tester Position Pin
No.

B/Box
No.
Pin Function Wire
Color
Key SW
Off Key SW
On Engine
Idle Engine
2000rpmECM
Connection Range(+) (-)
A14 A14 No Connection - - - - - - - - -
A15 A15 No Connection - - - - - - - - -
A16 A16 No Connection - - - - - - - - -
A17 A17 No Connection - - - - - - - - -
A18 A18 No Connection - - - - - - - - -
A19 A19 Intake Air
Temperature
(IAT) Sensor
Signal YEL/
GRN Less than 1V0 deg. C: Approx. 3.5V / 20 deg. C: Approx.
2.5V / 40 deg. C: Approx. 1.6V / 60 deg. C:
0.9V / 80 deg. C: 0.6V Connect DC V A19 B39
A20 A20 No Connection - - - - - - - - -
A21 A21 Engine Coolant
Temperature
(ECT) Sensor
Signal BLU/
RED Less than 1V0 deg. C: Approx. 3.6V / 20 deg. C: Approx.
2.4V / 40 deg. C: Approx. 1.4V / 60 deg. C:
3.4V / 80 deg. C: 2.6V Connect DC V A21 A22
A22 A22 EGR Valve &
ECT Sensor
Ground YEL/
BLK Continuity
with ground - - - Connect Ohm A22 GND
A23 A23 Crank Position
(CKP) Sensor
Signal YEL - - Wave form or approx. 1.9V Connect AC V A23 A25
A24 A24 Crank Position
(CKP) Sensor &
EGR Valve +5V
Supply RED/
BLU Less than 1V Approx. 5V Connect DC V A24 A25
A25 A25 Crank Position
(CKP) Sensor
Ground YEL/
BLK Continuity
with ground - - - Connect Ohm A25 GND
A26 A26 No Connection - - - - - - - - -
A27 A27 No Connection - - - - - - - - -
A28 A28 ECM Main
Relay BLU/
RED While main
relay is
activated:
Less than 1V
Main relay is
not activated:
10-14V Less than 1V Connect DC V A28 GND
A29 A29 No Connection - - - - - - - - -
A30 A30 No. 5 Ignition
Coil RED/
YEL - - Wave form - - - -

3.5L ENGINE DRIVEABILITY AND EMISSIONS 6E-51

GENERAL DESCRIPTION FOR ECM AND
SENSORS
Engine Control Module (ECM)


1 2
(1) A Port
(2) B Port


The engine control module (ECM) is located on the
common chamber. The ECM controls the following.

Fuel metering system

Ignition timing

On-board diagnostics for powertrain functions.

The ECM constantly observes the information from
various sensors. The ECM controls the systems tha
t
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

Exhaust oxygen content

Mass air flow

Intake air temperature

Engine coolant temperature

Crankshaft position

Camshaft position

Throttle position

Vehicle speed

Power steering pressure

Air conditioning request on or off

EGR valve position

Outputs (Systems controlled):

Ignition control

Fuel control

Idle air control

Fuel pump

EVAP canister purge

Air conditioning

Diagnostics functions

The vehicle with automatic transmission, the
interchange of data between the engine control module
(ECM) and the transmission control module (TCM) is
performed via a CAN-bus system.
The following signals are exchanged via the CAN-bus:

ECM to TCM:

ECM CAN signal status

Engine torque

Coolant temperature

Throttle position

Engine speed

A/C status

CAN valid counter

TCM to ECM:

Ignition timing retard request

Garage shift status

CAN valid counter

6E-52 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Mass Air Flow (MAF) Sensor & Intake Air
Temperature (IAT) Sensor





The MAF sensor is part of the intake air system.
It is fitted between the air cleaner & throttle body and
measure the mass air flowing into the engine.
The MAF sensor uses a hot wire element to determine
the amount of air flowing into the engine. (The wire
temperature reaches to 170 - 300C)
The MAF sensor assembly consist of a MAF senso
r
element and an intake air temperature sensor that are
both exposed to the air flow to be measured.
The MAF sensor element measures the partial air mass
through a measurement duct on the sensor housing.
Using calibration, there is an extrapolation to the entire
mass air flow to the engine.


















The IAT sensor is a thermistor. A temperature changes
the resistance value. And it changes voltage. In othe
r
words it measures a temperature value. Low air
temperature produces a high resistance.
The ECM supplies 5 volts signal to the IAT senso
r
through resisters in the ECM and measures the voltage.
The signal voltage will be high when the air temperature
is cold, and it will be low when the air temperature is
hot. Throttle Position Sensor (TPS)





1
2
(1) Throttle Position Sensor (TPS)
(2) Idle Air Control Valve (IACValve)


The TPS is a potentiometer connected to throttle shaf
t
on the throttle body.
The engine control module (ECM) monitors the voltage
on the signal line and calculates throttle position. As the
throttle valve angle is changed when accelerator pedal
moved. The TPS signal also changed at a moved
throttle valve.
As the throttle valve opens, the output
increases so that the output voltage should be high.

The throttle body has a throttle plate to control the
amount of air delivered to the engine. Engine coolant is
directed through a coolant cavity in the throttle body to
warm the throttle valve and to prevent icing.
Charac teristic of IA T Sens or
10 100 1000 10000 100000-3010 50 90130Temper atur e (

)
Resistance (Ω)

3.5L ENGINE DRIVEABILITY AND EMISSIONS 6E-53
Idle Air Control (IAC) Valve








Step
CoilAB CD
Coil A High
(EC M B13)On On
Coil A Low
(EC M B16)On On
Coil B High
(EC M B14)On On
Coil B Low
(EC M B17)On On

(IAC Valve Close Direction)
(IAC Valve Open Direction)



The idle air control valve (IAC) valve is two directional
and gives 2-way control. It has a stepping moto
r
capable of 256 steps, and also has 2 coils. With power
supply to the coils controlled steps by the engine control
module (ECM), the IAC valve's pintle is moved to adjus
t
idle speed, raising it for fast idle when cold or there is
extra load from the air conditioning or power steering.
By moving the pintle in (to decrease air flow) or out (to
increase air flow), a controlled amount of the air can
move around the throttle plate. If the engine speed is
too low, the engine control module (ECM) will retract the
IAC pintle, resulting in more air moving past the throttle
plate to increase the engine speed.
If the engine speed is too high, the engine control
module (ECM) will extend the IAC pintle, allowing less
air to move past the throttle plate, decreasing the
engine speed.

The IAC pintle valve moves in small step called counts.
During idle, the proper position of the IAC pintle is
calculated by the engine control module (ECM) based
on battery voltage, coolant temperature, engine load,
and engine speed.
If the engine speed drops below a specified value, and
the throttle plate is closed, the engine control module
(ECM) senses a near-stall condition. The engine control
module (ECM) will then calculate a new IAC pintle valve
position to prevent stalls. If the IAC valve is disconnected and reconnected with
the engine running, the idle speed will be wrong. In this
case, the IAC must be reset. The IAC resets when the
key is cycled "On" then "Off". When servicing the IAC, i
t
should only be disconnected or connected with the
ignition "Off".
The position of the IAC pintle valve affects engine start-
up and the idle characteristic of the vehicle.
If the IAC pintle is fully open, too much air will be
allowed into the manifold. This results in high idle
speed, along with possible hard starting and lean
air/fuel ratio.

Camshaft Position (CMP) Sensor








12
(1) Camshaft Position (CMP) Sensor
(2) EGR Valve


With the use of sequential multi-point fuel injection, a
hall element type camshaft position (CMP) is adopted to
provide information to be used in making decisions on
injection timing to each cylinder. It is mounted on the
rear of the left-hand cylinder head and sends signals to
the ECM.
One pulse is generated per two rotations of crankshaft.