switch ISUZU TF SERIES 2004 Workshop Manual

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-9




(1) Vehicle Speed Sensor (VSS)



(1) Power Steering Pressure Switch

3.5L ENGINE DRIVEABILITY AND EMISSIONS 6E-27
CONNECTOR LIST
No. Connector face No. Connector face
B-24
Green
Meter-B C-108
WhiteJ/B E1
B-56
White
J/B I4 C-109
SilverBody-LH ; ground
B-58
Black
Check connector E-2
Magnetic clutch
B-62
White
Ignition switch (IGSUB : G1) E-6

Fuel injector
B-63
White
Ignition switch (IGSUB : G2) E-7

Fuel injector
B-68


Immobilizer E-8

Fuel injector
C-2
Silver
Engine room-RH ground E-9

Fuel injector
C-24

Triple pressure switch E-51

Fuel injector
C-94

Gray TCM-(A) E-52

Fuel injector
C-107
White
J/B E2 E-53

Ignition coil

6E-28 3.5L ENGINE DRIVEABILITY AND EMISSIONS

No. Connector face No. Connector face
E-54

Ignition coil E-64

Oil pressure switch (P/STRG)
E-55

Ignition coil E-66
Duty solenoid
E-56

Ignition coil E-68

Throttle position sensor
E-57

Ignition coil E-69


Temperature sensor
E-58

Ignition coil E-70
IACV
E-59


Crank position sensor E-72

Engine earth-A
E-60

ECM-A E-73

Engine earth-A
E-61


ECM-B E-74
Engine earth-B
E-62

Cam position sensor E-76

EGR valve
E-63

MAF sensor E-77

O2 sensor RH-Front

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

3.5L ENGINE DRIVEABILITY AND EMISSIONS 6E-47
Signal or Continuity Tester Position Pin
No. B/Box
No. Pin Function Wire
Color
Key SW Off Key SW On Engine IdleEngine
2000rpm ECM
Connection Range (+) (-)
B16 B16 Idle Air Control
(IAC) Valve
Coil A Low BLU/
RED Less than 1V Less than 1V / 10-14V Connect DC V B16 GND
B17 B17 Idle Air Control
(IAC) Valve
Coil B Low BLU/
BLKLess than 1V Less than 1V / 10-14V Connect DC V B17 GND
B18 B18 Check Engine
Lamp
(Immobilizer
Control Unit
Terminal B7) BRN/
YELLess than 1V Less than 1VLamp is turned on:
Less than 1V
Lamp is turned off: 10-14VConnect DC V B18 GND
B19 B19 Fuel Pump
Relay GRN/
WHT Less than 1V While relay is
activated:
10-14V
Relay is not
activated:
Less than 1V10-14V Connect DC V B19 GND
B20 B20 Mass Air Flow
(MAF) Sensor BLK/
YELLess than 1V Approx. 0.47VApprox. 1.5V
at 750 rpmApprox. 2V Connect DC V B20 GND
B21 B21 Bank 1 Oxygen
Sensor Signal PNK Less than 1V Approx. 0.4V 0.1 - 0.9V Connect DC V B21 B22
B22 B22 Bank 1 Oxygen
Sensor Ground BLU/
YELContinuity
with ground - - - Connect Ohm B22 GND
B23 B23 Bank 2 Oxygen
Sensor Signal RED Less than 1V Approx. 0.4V 0.1 - 0.9V Connect DC V B23 B24
B24 B24 Bank 2 Oxygen
Sensor Ground BLU/
BLKContinuity
with ground - - - Connect Ohm B24 GND
B25 B25 To Data Link
Connector
No.6 BLK/
GRN - - - - - - - -
B26 B26 Throttle
Position
Sensor (TPS)
Signal BLU Less than 1V Approx. 0.5V Approx. 0.6V Connect DC V B26 B39
B27 B27 TPS & Cam
Position
Sensor +5V
Supply GRN Less than 1V Approx. 5V Connect DC V B27 B39
B28 B28 Camshaft
Position (CMP)
Sensor Signal BLU - - Wave form - - - -
B29 B29 Inhibitor Switch
(AT Only) BLK Less than 1V P or N range: Less than 1V
Other than P or N range: 10-14V Connect DC V B29 GND
B30 B30 Power Steering
Pressure
Switch GRN/
YELLess than 1V Pressure switch is turned on: Less than 1V
Pressure Switch is turned off: 10-14V Connect DC V B30 GND
B31 B31 A/C Thermo
Relay GRN/
BLKLess than 1V A/C request is activated: 10-14V
A/C request is not activated: Less than 1VConnect DC V B31 GND

6E-48 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 IdleEngine
2000rpm ECM
Connection Range (+) (-)
B32 B32 Vehicle Speed
Signal
(Immobilizer
Control Unit
Terminal B8) WHT - - Wave form or approx. 6.5V at
20km/h Connect AC V B32 GND
B33 B33 Ignition Switch BLU/
YELLess than 1V 10-14V Connect DC V B33 GND
B34 B34 Back Up
Power Supply RED/
WHT 10-14V Connect DC V B34 GND
B35 B35 No Connection - - - - - - - - -
B36 B36 ECM Main
Relay RED/
BLUWhile main
relay is
activated:
10-14V
Main relay is
not activated:
Less than 1V 10-14V Connect DC V B36 GND
B37 B37 ECM Main
Relay RED/
BLUWhile main
relay is
activated:
10-14V
Main relay is
not activated:
Less than 1V 10-14V Connect DC V B37 GND
B38 B38 To Data Link
Connect to No.
2 GRN - - - - - - - -
B39 B39 TPS, MAF, IAT
& CMP Sensor
Ground RED Continuity
with ground - - - Connect Ohm B39 GND
B40 B40 No Connection - - - - - - - - -

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-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.

3.5L ENGINE DRIVEABILITY AND EMISSIONS 6E-65
3. Check Bulletins and
Troubleshooting Hints
NOTE: As estimated 30 percent of successful
vehicle repairs are diagnosed with this step!
What you should do
You should have enough information gained from
preliminary checks to accurately search for a bulletin
and other related service information. Some service
manual sections provide troubleshooting hints that
match symptoms with specific complaints.
What resources you should use
You should use the following resources for assistance
in checking for bulletins and troubleshooting hints:

Printed bulletins

Access ISUZU Bulletin Web site

Videotapes

Service manual
4. Perform Service Manual
Diagnostic Checks
What you should do
The “System Checks” in most service manual sections
and in most cells of section 8A (electrical) provide you
with:


A systematic approach to narrowing down the
possible causes of a system fault

Direction to specific diagnostic procedures in the
service manual

Assistance to identify what systems work correctly
What resources you should use
Whenever possible, you should use the following
resources to perform service manual checks:

Service manual

Technical equipment (for viewing DTCs and
analyzing data)

Digital multimeter and circuit testing tools

Other tools as needed
5a and 5b. Perform Service Manual
Diagnostic Procedures
NOTE: An estimated 40 percent of successful
vehicle repairs are diagnosed with these steps!

What you should do
When directed by service manual diagnostic checks,
you must then carefully and accurately perform the
steps of diagnostic procedures to locate the fault related
to the customer complaint.
What resources you should use
Whenever appropriate, you should use the following
resources to perform service manual diagnostic
procedures:

Service manual

Technical equipment (for analyzing diagnostic
data)

Digital multimeter and circuit testing tools

Essential and special tools
5c. Technician Self Diagnoses
When there is no DTC stored and no matching
symptom for the condition identified in the service
manual, you must begin with a thorough understanding
of how the system(s) operates. Efficient use of the
service manual combined with you experience and a
good process of elimination will result in accurate
diagnosis of the condition.
What you should do
Step 1: Identify and understand the suspect
circuit(s)
Having completed steps 1 through 4 of the Strategy
Based Diagnostics chart, you should have enough
information to identify the system(s) or sub-system(s)
involved. Using the service manual, you should
determine and investigate the following circuit
characteristics:

Electrical:
 How is the circuit powered (power distribution
charts and/or fuse block details)?
 How is the circuit grounded (ground distribution
charts)?
 How is the circuit controlled or sensed (theory
of operation):
 If it is a switched circuit, is it normally open o
r
normally closed?
 Is the power switched or is the ground
switched?
 Is it a variable resistance circuit (ECT senso
r
or TPS, for example)?
 Is it a signal generating device (MAF senso
r
of VSS, for example)?