wiring ISUZU TF SERIES 2004 Workshop Manual

3.5L ENGINE DRIVEABILITY AND EMISSIONS 6E-259
CIRCUIT DESCRIPTION
The engine control module (ECM) monitors the EGR
valve pintle position input to ensure that the valve
responds properly to commands from the PCM, and to
detect a fault if pintle position is differen
t
fromcommanded position.
DIAGNOSTIC AIDS
Check for the following conditions:

Excessive carbon deposit on EGR valve shaf
t
maycause EGR stuck open or unsmooth operation.
Those carbon deposit may occur by unusual
portoperation. Clean up carbon may make
smoothfunction of EGR valve.


Poor connection or damaged harness Inspec
t
thewiring harness for damage. If the harness
appears to be OK, observe the EGR actual position
display on the Tech 2 while moving connectors and
wiring harnesses related to EGR valve. A change in
the display will indicate the location of the fault.

Diagnostic Trouble Code (DTC) P0404 (Flash Code 32) EGR Circuit
Range/Perfomance (Open Valve)
Diagnostic Trouble Code (DTC) P1404 (Flash Code 32) EGR Circuit
Range/Perfomance (Closed Valve)

Step Action Value (s) Yes No
1
Was the "On-Board Diagnostic (OBD) System Check"
performed?
- Go to Step 2 Go to On Board
Diagnostic (OBD)
System Check
2
1. Connect the Tech 2.
2. Review and record the failure information.
3. Select "F0: Read DTC Infor By Priority" in "F0:
Diagnostic Trouble Code".
Is the DTC P0404 or P1404 stored as "Present
Failure"?
- Go to Step 3 Refer to
Diagnostic Aids
and Go to Step 3
3
1. Using the Tech2, ignition "On" and engine "Off".
2. Select "Clear DTC Information" with the Tech2 and
clear the DTC information.
3. Operate the vehicle and monitor the "F5: Failed
This Ignition" in "F2: DTC Information"
Was the DTC P0404 or P1404 stored in this ignition
cycle?
- Go to Step 4 Refer to
Diagnostic Aids
and Go to Step 4

3.5L ENGINE DRIVEABILITY AND EMISSIONS 6E-263
DIAGNOSTIC TROUBLE CODE (DTC) P0405 (FLASH CODE 32)
EGR CIRCUIT LOW



RUW46EMF000201

Condition For Setting The DTC and Action Taken When The DTC Sets
Flash
Code Code Type DTC Name DTC Setting Condition Fail-Safe (Back Up)
32 P0405 B EGR Circuit Low 1. No DTC relating to EGR circuit range/performance.
2. EGR solenoid valve on-duty ratio is more than 40%.
3. EGR position sensor output voltage is below 0.3V. No fail-safe function.

CIRCUIT DESCRIPTION
The engine control module (ECM) monitors the EGR
valve pintle position input to ensure that the valve
responds properly to command from the ECM. If curren
t
pintle position voltage indicates less than 0.3 V the ECM
will set DTC P0405.

DIAGNOSTIC AIDS
Check for the following conditions:
 Poor connection or damaged harness –Inspect the
wiring harness for damage. If the harness appears to
be OK, observe the EGR actual position display on
the Tech 2 while moving connectors and wiring
harnesses related to EGR valve. A change in the
display will indicate the location of the fault.

6E-268 3.5L ENGINE DRIVEABILITY AND EMISSIONS
DIAGNOSTIC TROUBLE CODE (DTC) P0406 (FLASH CODE 32)
EGR CIRCUIT HIGH



RUW46EMF000201

Condition For Setting The DTC and Action Taken When The DTC Sets
Flash
Code Code Type DTC Name DTC Setting Condition Fail-Safe (Back Up)
32 P0406 B EGR Circuit High 1. No DTC relating to EGR circuit range/performance.
2. EGR solenoid valve on-duty ratio is below 40%.
3. EGR position sensor output voltage is more than 4.6V. No fail-safe function.


CIRCUIT DESCRIPTION
The engine control module (ECM) monitors the EGR
valve pintle position input to ensure that the valve
responds properly to command from the ECM. If curren
t
pintle position voltage indicates more than 4.6 V the
ECM will set DTC P0406.

DIAGNOSTIC AIDS
Check for the following conditions:
 Poor connection or damaged harness –Inspect the
wiring harness for damage. If the harness appears to
be OK, observe the EGR actual position display on
the Tech 2 while moving connectors and wiring
harnesses related to EGR valve. A change in the
display will indicate the location of the fault.

3.5L ENGINE DRIVEABILITY AND EMISSIONS 6E-275
CIRCUIT DESCRIPTION
The canister purge solenoid valve is controlled by the
Engine Train Control Module (ECM).
At an appropriate time, the EVAP canister purge
solenoid is “ON," allowing engine vacuum to draw a
small vacuum on the entire evaporative emissions
system.
DIAGNOSTIC AIDS
An intermittent may be caused by the following:
 Poor connections.
 Mis routed harness.
 Rubbed through wire insulation.
 Broken wire inside the insulation.
Check for the following conditions:

 Poor connection at ECM-Inspect harness connectors
for backed out terminals, improper mating, broken
locks, improperly formed or damaged terminals, and
poor terminal to wire connection.
 Damaged harness-Inspect the wiring harness fo
r
damage. If the harness appears to be OK, observe
the EVAP purge solenoid display on the Tech 2 while
moving connectors and wiring harnesses related to
the sensor.
A change in the display will indicate the location o
f
the fault. If DTC P0444 or P0445 cannot be
duplicated, the information included in the Failure
Records data can be useful in determined vehicle
mileage since the DTC was last set.
If it is determined that the DTC occurs intermittently,
performing the DTC P0444 or P0445 Diagnostic
Chart may isolate the cause of the fault.


Diagnostic Trouble Code (DTC) P0444 EVAP Purge Solenoid
Valve Circuit Low Voltage
Diagnostic Trouble Code (DTC) P0445 EVAP Purge Solenoid
Valve Circuit High Voltage

Step Action Value (s) Yes No
1
Was the "On-Board Diagnostic (OBD) System Check"
performed?
- Go to Step 2 Go to On Board
Diagnostic (OBD)
System Check
2
1. Connect the Tech 2.
2. Review and record the failure information.
3. Select "F0: Read DTC Infor By Priority" in "F0:
Diagnostic Trouble Code".
Is the DTC P0444 or P0445 stored as "Present
Failure"?
- Go to Step 3 Refer to
Diagnostic Aids
and Go to Step 3
3
1. Using the Tech2, ignition "On" and engine "Off".
2. Select "Clear DTC Information" with the Tech2 and
clear the DTC information.
3. Operate the vehicle and monitor the "F5: Failed
This Ignition" in "F2: DTC Information"
Was the DTC P0444 or P0445 stored in this ignition
cycle?
- Go to Step 4 Refer to
Diagnostic Aids
and Go to Step 4

3.5L ENGINE DRIVEABILITY AND EMISSIONS 6E-279
DIAGNOSTIC TROUBLE CODE (DTC) P0500 (FLASH CODE 24) VEHICLE
SPEED SENSOR (VSS) CIRCUIT RANGE/PERFORMANCE



RTW46EMF000301

Condition For Setting The DTC and Action Taken When The DTC Sets
Flash
Code Code Type DTC Name DTC Setting Condition Fail-Safe (Back Up)
24 P0500 B Vehicle Speed Sensor
Circuit
Range/Performance 1. Engine speed is below 5000rpm.
2. Under fuel cut operation.
3. Vehicle speed sensor output is below 1km/h.
Above conditions are met for 4 seconds. The ECM use 10km/h condition as
substitute.


CIRCUIT DESCRIPTION
The vehicle speed sensor has a magnet rotated by the
transmission output shaft. Attached to the sensor is a
hall effect circuit the interacts with the magnetic field
treated by the rotating magnet. A 12-volt operating
supply for the speed sensor hall circuit is supplied from
the meter fuse. The VSS pulses to ground the 9-vol
t
signal sent from the Engine Control Module (ECM) on
the reference circuit. The ECM interprets vehicle speed
by the number of pulses to ground per second on the
reference circuit.

DIAGNOSTIC AIDS
An intermittent may be caused by a poor connection,
rubbed–through wire insulation or a wire broken inside
the insulation. Check for:
 Poor connection —Inspect the ECM harness and
connectors for improper mating, broken locks,
improperly formed or damaged terminals, and poo
r
terminal-to-wire connection.
 Damaged harness —Inspect the wiring harness fo
r
damage.

3.5L ENGINE DRIVEABILITY AND EMISSIONS 6E-297
Condition For Setting The DTC and Action Taken When The DTC Sets
Flash
Code Code Type DTC Name DTC Setting Condition Fail-Safe (Back Up)
P1508 B Idle Air Control System
Low/Closed 1. No DTC relating to MAF sensor, IAT sensor, ECT sensor,
TPS, CMP sensor, CKP sensor, VSS and system voltage.
2. Engine speed is between 675rpm and 6000rpm.
3. Engine coolant temperature is more than 75
C.
4. Intake air temperature is between -10
C and 80
C.
5. Vehicle is stopping.
6. Small amount of intake air through the idle air control
valve. (Idle air control valve is sticking at close position.)
Above conditions are met for 2 seconds. 22
P1509 B Idle Air Control System
High/Open 1. No DTC relating to MAF sensor, IAT sensor, ECT sensor,
TPS, CMP sensor, CKP sensor, VSS and system voltage.
2. Engine speed is between 675rpm and 6000rpm.
3. Engine coolant temperature more than 75
C.
4. Intake air temperature is between -10
C and 80
C.
5. Vehicle is stopping.
6. Large amount of intake air through the idle air control
valve. (Idle air control valve is sticking at open position.)
Above conditions are met for 2 seconds. Fuel cut is operated at high idle
speed.

CIRCUIT DESCRIPTION
The engine control module (ECM) controls engine idle
speed by adjusting the position of the idle air control
(IAC) motor pintle. The IAC is a bi-directional steppe
r
motor driven by two coils. The ECM applies current to
the IAC coils in steps (counts) to extend the IAC pintle
into a passage in the throttle body to decrease air flow.
The ECM reverses the current to retract the pintle,
increasing air flow. This method allows highly accurate
control of idle speed and quick response to changes in
engine load. If the ECM detects a condition where too
low of an idle speed is present and the ECM is unable
to adjust idle speed by increasing the IAC counts, DTC
P1508 or P1509 will set, indicating a problem with the
idle control system.

DIAGNOSTIC AIDS
Check for the following conditions:
 Poor connection at ECM or IAC motor –Inspec
t
harness connectors for backed-out terminals,
improper mating, broken locks, improperly formed o
r
damaged terminals, and poor terminal-to-wire
connection.
 Damaged harness – Inspect the wiring for damage.
 Restricted air intake system – Check for a possible
collapsed air intake duct, restricted air filter element,
or foreign objects blocking the air intake system.

6E-304 3.5L ENGINE DRIVEABILITY AND EMISSIONS
DIAGNOSTIC TROUBLE CODE (DTC) P1601 (FLASH CODE 65) CAN BUS OFF



RTW46EMF000301

Condition For Setting The DTC and Action Taken When The DTC Sets
Flash
Code Code Type DTC Name DTC Setting Condition Fail-Safe (Back Up)
65 P1601 D CAN BUS Off CAN BUS off condition is detected consecutively. Torque reduction control is disable.


Circuit Description
The engine control system in 6VE1 uses high speed
CAN bus system. The individual CAN bus systems are
connected via two interfaces and can exchange
information and data. This allows control modules tha
t
are connected to different CAN bus systems to
communicate. Engine control modules (ECM) in the
vehicle that require continuous, rapid communication
are connected to the high speed CAN bus. The engine
is continuously notified of the current engine load
status. Since the ECM has to react immediately to load
status changes, rapid communication is required
between the ECM and the automatic transmission
control module. The high speed CAN bus in the 6VE1 is
designed as a two-wire CAN bus (twisted pair). The
wires are shielded and twisted. The engine rate is 500
K
band.

Diagnostic Aids
 Inspect the wiring for poor electrical connection at the
ECM. Look for possible bent, backed out, deformed
or damaged terminals. Check for weak terminal
tension as well. Also check for a chafed wire tha
t
could short to bare metal or other wiring. Inspect for a
broken wire inside the insulation.
 When diagnosing for a possible intermittent short o
r
open condition, move the wiring harness while
observing test equipment for a change.
 Inspect the wiring for EMI (Erectro-Magnetic
Interference). Check that all wires are properly routed
away from coil, and generator. Also check fo
r
improperly installed electrical options. When this test
is performed, turn “OFF" on electronic autoparts
switches to improperly for a noise preventing.

6E-310 3.5L ENGINE DRIVEABILITY AND EMISSIONS
DIAGNOSTIC TROUBLE CODE (DTC) U2104 (FLASH CODE 67) CAN BUS
RESET COUNTER OVER-RUN



RTW46EMF000301
Condition For Setting The DTC and Action Taken When The DTC Sets
Flash
Code Code Type DTC Name DTC Setting Condition Fail-Safe (Back Up)
67 U2104 D CAN BUS Reset
Counter Overrun 1. No DTC CAN BUS Off.
2. CAN valid counter does not change for 2 seconds. Torque reduction control is disable.

CIRCUIT DESCRIPTION
The engine control system in 6VE1 uses high speed
CAN bus system. The individual CAN bus systems are
connected via two interfaces and can exchange
information and data. This allows control modules tha
t
are connected to different CAN bus systems to
communicate. Engine control modules (ECM) in the
vehicle that require continuous, rapid communication
are connected to the high speed CAN bus. The engine
is continuously notified of the current engine load
status. Since the ECM has to react immediately to load
status changes, rapid communication is required
between the ECM and the automatic transmission
control module. The high speed CAN bus in the 6VE1 is
designed as a two-wire CAN bus (twisted pair). The
wires are shielded and twisted. The engine rate is 500
K
band.

DIAGNOSTIC AIDS
 Inspect the wiring for poor electrical connection at the
ECM. Look for possible bent, backed out, deformed
or damaged terminals. Check for weak terminal
tension as well. Also check for a chafed wire tha
t
could short to bare metal or other wiring. Inspect for a
broken wire inside the insulation.
 When diagnosing for a possible intermittent short o
r
open condition, move the wiring harness while
observing test equipment for a change.
 Inspect the wiring for EMI (Erectro-Magnetic
Interference). Check that all wires are properly routed
away from coil, and generator. Also check fo
r
improperly installed electrical options. When this test
is performed, turn “OFF" on electronic auto parts
switches to improperly for a noise preventing.

3.5L ENGINE DRIVEABILITY AND EMISSIONS 6E-317
DIAGNOSTIC TROUBLE CODE (DTC) P1626 IMMOBILIZER NO SIGNAL



RTW46EMF000301

Condition For Setting The DTC and Action Taken When The DTC Sets
Flash
Code Code Type DTC Name DTC Setting Condition Fail-Safe (Back Up)
67 P1626 - Immobilizer No Signal No response from immobilizer control unit. 1. Engine does not start.
2. Check engine lamp flash.

CIRCUIT DESCRIPTION
The Engine Control Module (ECM) decides whether that
is an abnomality in the immobilizer control system. DTC
P1626 is recorded by the ECM when no response from
immoblizer.

DIAGNOSTIC AIDS
Check for the following conditions:

Poor connection at Engine Control Module (ECM)
and immobilizer inspect harness connectors for
backed out terminals, improper mating, broken
locks, improperly formed or damaged terminals, and
poor terminal to wire connection.

Damaged harness-inspect the wiring harness for
damage, if the harness appears to be OK,
disconnect the ECM and immobilizer, turn the
ignition "ON" and observe a voltmeter connected to
the suspect driver circuit at the ECM and immobilizer
harness connector while moving connectors and
wiring harnesses relates to the Check Engine Lamp
(MIL). A change in voltage will indicate the location
of the fault.

3.5L ENGINE DRIVEABILITY AND EMISSIONS 6E-323
DIAGNOSTIC TROUBLE CODE (DTC) P1631 IMMOBILIZER WRONG SIGNAL



RTW46EMF000301

Condition For Setting The DTC and Action Taken When The DTC Sets
Flash
Code Code Type DTC Name DTC Setting Condition Fail-Safe (Back Up)
67 P1631 - Immobilizer Wrong
Signal Received response is not correct. 1. Engine does not start.
2. Check engine lamp flash.

CIRCUIT DESCRIPTION
The ECM decides whether that is an abnormality in the
immobilizer control system. DTC P1631 is recorded by
the ECM when received response was not correct.

DIAGNOSTIC AIDS
Check for the following conditions:

Poor connection at Engine Control Module (ECM)
and immobilizer inspect harness connectors for
backed out terminals, improper mating, broken
locks, improperly formed or damaged terminals, and
poor terminal to wire connection.

Damaged harness-inspect the wiring harness for
damage, if the harness appears to be OK,
disconnect the ECM and immobilizer, turn the
ignition "ON" and observe a voltmeter connected to
the suspect driver circuit at the ECM and immobilizer
harness connector while moving connectors and
wiring harnesses relates to the Check Engine Lamp
(MIL). A change in voltage will indicate the location
of the fault.