mileage ISUZU TF SERIES 2004 Workshop Manual

6E-150 3.5L ENGINE DRIVEABILITY AND EMISSIONS
CIRCUIT DESCRIPTION
The mass air flow (MAF) sensor measures the amount
of air which passes through it into the engine during a
given time. The Engine Control Module (ECM) uses the
mass air flow information to monitor engine operating
conditions for fuel delivery calculations. A large quantity
of air entering the engine indicates an acceleration o
r
high load situation, while a small quantity of air indicates
deceleration or idle.
The MAF sensor produces a frequency signal which
can be monitored using a Tech 2. The frequency will
vary within a range of around 5 to 8 g/s at idle to around
25 to 40 g/s at maximum engine load. DTC P0102 will
be set if the signal from the MAF sensor is below the
possible range of a normally operating MAF sensor.
.

DIAGNOSTIC AIDS
Check for the following conditions:
 Poor connection at ECM – Inspect harness
connectors for backed-out terminals, imprope
r
mating, broken locks, improperly formed or damaged
terminals, and poor terminal-to-wire connection.
 Misrouted harness – Inspect the MAF senso
r
harness to ensure that it is not routed too close to
high voltage wires.
 Damaged harness –Inspect the wiring harness fo
r
damage. If the harness appears to be OK, observe
the Tech 2 while moving connectors and wiring
harnesses related to the MAF sensor. A change in
the display will indicate the location of the fault.
If DTC P0102 cannot be duplicated, the information
included in the Failure Records data can be useful in
determining vehicle mileage since the DTC was last set


Diagnostic Trouble Code (DTC) P0102 (Flash Code 61) Mass Air Flow Sensor
Circuit Low Input
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 P0102 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 P0102 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-155
CIRCUIT DESCRIPTION
The mass air flow (MAF) sensor measures the amount
of air which passes through it into the engine during a
given time. The Engine Control Module (ECM) uses the
mass air flow information to monitor engine operating
conditions for fuel delivery calculations. A large quantity
of air entering the engine indicates an acceleration o
r
high load situation, while a small quantity of air indicates
deceleration or idle.
The MAF sensor produces a frequency signal which
can be monitored using a Tech 2. The frequency will
vary within a range of around 5

8 g/s at idle to around
25 to 40 g/s at maximum engine load. DTC P0103 will
be set if the signal from the MAF sensor is above the
possible range of a normally operating MAF sensor.

DIAGNOSTIC AIDS
If DTC P0103 cannot be duplicated, the information
included in the Failure Records data can be useful in
determining vehicle mileage since the DTC was last set.


Diagnostic Trouble Code (DTC) P0103 (Flash Code 61)
Mass Air Flow Sensor Circuit High Input
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 P0103 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 P0103 stored in this ignition cycle?
- Go to Step 4 Refer to
Diagnostic Aids
and Go to Step 4
4
Check for poor/faulty connection at the MAF sensor or
ECM connector. If a poor/faulty connection is found,
repair as necessary.
Was the problem found?


 E-61(B)
E-63






- Verify repair Go to Step 5

6E-158 3.5L ENGINE DRIVEABILITY AND EMISSIONS
DIAGNOSTIC TROUBLE CODE (DTC) P0112 (FLASH CODE 23) INTAKE AIR
TEMPERATURE (IAT) SENSOR LOW INPUT

RUW46EMF000101

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)
23 P0112 A Intake Air Temperature
Sensor Low Input
IAT sensor output voltage is below 0.08V. The ECM use 40C conditions as
substitute.

CIRCUIT DESCRIPTION
The intake air temperature (IAT) sensor is a thermistor
which measures the temperature of the air entering the
engine. The Engine Control Module (ECM) applies 5
volts through a pull-up resistor to the IAT sensor. When
the intake air is cold, the sensor resistance is high and
the ECM will monitor a high signal voltage on the IAT
signal circuit. If the intake air is warm, the sensor
resistance is lower, causing the ECM to monitor a lower
voltage. DTC P0112 will set when the ECM detects an
excessively low signal voltage on the intake air
temperature sensor signal circuit.
DIAGNOSTIC AIDS
Check for the following conditions:
 Poor connection at ECM – Inspect harness
connectors for backed-out terminals, imprope
r
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 IAT display on the Tech 2 while moving
connectors and wiring harnesses related to the IAT
sensor. A change in the IAT display will indicate the
location of the fault.
If DTC P0112 cannot be duplicated, the information
included in the Failure Records data can be useful in
determining vehicle mileage since the DTC was last set.

3.5L ENGINE DRIVEABILITY AND EMISSIONS 6E-163
DIAGNOSTIC TROUBLE CODE (DTC) P0113 (FLASH CODE 23) INTAKE AIR
TEMPERATURE (IAT) SENSOR HIGH INPUT

RUW46EMF000101

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)
23 P0113 A Intake Air Temperature
Sensor High Input
IAT sensor output voltage is more than 4.9V. The ECM use 40C conditions as
substitute.

CIRCUIT DESCRIPTION
The intake air temperature (IAT) sensor is a thermistor
which measures the temperature of the air entering the
engine. The Engine Control Module (ECM) applies 5
volts through a pull-up resistor to the IAT sensor. When
the intake air is cold, the sensor resistance is high and
the ECM will monitor a high signal voltage on the IAT
signal circuit. If the intake air is warm, the senso
r
resistance is lower causing the ECM to monitor a lower
voltage. DTC P0113 will set when the ECM detects an
excessively high signal voltage on the intake ai
r
temperature sensor signal circuit.


DIAGNOSTIC AIDS
Check for the following conditions:
 Poor connection at ECM – Inspect harness
connectors for backed-out terminals, imprope
r
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 IAT display on the Tech 2 while moving
connectors and wiring harnesses related to the IAT
sensor. A change in the IAT display will indicate the
location of the fault.
If DTC P0113 cannot be duplicated, the information
included in the Failure Records data can be useful in
determining vehicle mileage since the DTC was last set.

6E-168 3.5L ENGINE DRIVEABILITY AND EMISSIONS
DIAGNOSTIC TROUBLE CODE (DTC) P0117 (FLASH CODE 14) ENGINE
COOLANT TEMPERATURE (ECT) SENSOR LOW INPUT



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)
14 P0117 A Engine Coolant
Temperature Sensor
Low Input
ECT sensor output voltage is below 0.08V. The ECM uses default engine
coolant temperature value based on
start-up ECT and time from start.

Circuit Description
The engine coolant temperature (ECT) sensor is a
thermistor mounted on a coolant crossover pipe at the
rear of the engine. The Engine Control Module (ECM)
applies a voltage (about 5 volts) through a pull-up
resistor to the ECT signal circuit. When the engine
coolant is cold, the sensor (thermistor) resistance is
high, therefore the ECM will measure a high signal
voltage. As the engine coolant warms, the senso
r
resistance becomes lower, and the ECT signal voltage
measured at the ECM drops.

DIAGNOSTIC AIDS
Check for the following conditions:
 Poor connection at ECM – Inspect harness
connectors for backed-out terminals, imprope
r
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 ECT display on the Tech 2 while moving
connectors and wiring harnesses related to the ECT
sensor. A change in the ECT display will indicate the
location of the fault.
If DTC P0117 cannot be duplicated, the information
included in the Failure Records data can be useful in
determining vehicle mileage since the DTC was last set.
If it is determined that the DTC occurs intermittently.

3.5L ENGINE DRIVEABILITY AND EMISSIONS 6E-173
DIAGNOSTIC TROUBLE CODE (DTC) P0118 (FLASH CODE 14) ENGINE
COOLANT TEMPERATURE (ECT) SENSOR HIGH INPUT



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)
14 P0118 A Engine Coolant
Temperature Sensor
High Input ECT sensor output voltage is more than 4.8V. The ECM uses default engine
coolant temperature value based on
start-up ECT and time from start.

CIRCUIT DESCRIPTION
The engine coolant temperature (ECT) sensor is a
thermistor mounted in on a coolant crossover pipe a
t
the rear of the engine. The Engine Control Module
(ECM) applies a voltage (about 5 volts) through a
pull-up resistor to the ECT signal circuit. When the
engine coolant is cold, the sensor (thermistor)
resistance is high, therefore the ECM will measure a
high signal voltage. As the engine coolant warms, the
sensor resistance becomes less, and the ECT signal
voltage measured at the ECM drops.

DIAGNOSTIC AIDS
Check for the following conditions:
 Poor connection at ECM – Inspect harness
connectors for backed-out terminals, imprope
r
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 ECT display on the Tech 2 while moving
connectors and wiring harnesses related to the ECT
sensor. A change in the ECT display will indicate the
location of the fault.
If DTC P0118 cannot be duplicated, the information
included in the Failure Records data can be useful in
determining vehicle mileage since the DTC was last set.

6E-180 3.5L ENGINE DRIVEABILITY AND EMISSIONS
CIRCUIT DESCRIPTION
The TPS circuit provides a voltage signal that changes
relative to throttle blade angle. The signal voltage will
vary from about 0.6 volts at closed throttle to about 4.5
volts at wide open throttle (WOT).
The TPS signal is one of the most important inputs
used by the Engine Control Module (ECM) for fuel
control and many of the ECM-controlled outputs. The
ECM monitors throttle position and compares actual
throttle position from the TPS to a predicted TPS value
calculated from engine speed. If the ECM detects an
out-of-range condition, DTC P0121 will set.

DIAGNOSTIC AIDS
Check for the following conditions:
 Poor connection at ECM – Inspect harness
connectors for backed-out terminals, imprope
r
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 ECT display on the Tech 2 while moving
connectors and wiring harnesses related to the
sensor. A change in the display will indicate the
location of the fault.
If DTC P0121 cannot be duplicated, the information
included in the Failure Records data can be useful in
determining vehicle mileage since the DTC was last set.

Diagnostic Trouble Code (DTC) P0121 (Flash Code 21) Throttle Position
Sensor (TPS) Circuit Range/Performance
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 P0121 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 P0121 stored in this ignition cycle?
- Go to Step 4 Refer to
Diagnostic Aids
and Go to Step 4
4

1. Using the Tech 2, ignition "On" and engine "Off".
2. Monitor the "Throttle Position" in the data display.
Does the Tech 2 indicate correct "Throttle Position"
from 0% to 100% depending on accelerator pedal
operation?
- Go to Step 6 Go to Step 5
5
1. Using the Tech 2, ignition "On" and engine "Off
2. Monitor the "Throttle Position" in the data display.
3. Adjust the TPS within 0% to 100%.
Was the problem solved?
- Verify repair Go to Step 12

3.5L ENGINE DRIVEABILITY AND EMISSIONS 6E-183
DIAGNOSTIC TROUBLE CODE (DTC) P0122 (FLASH CODE 21) THROTTLE
POSITION SENSOR CIRCUIT LOW INPUT



RUW46EMF000101

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)
21 P0122 A Throttle Position
Sensor Low Input TPS output voltage is below 0.24V. The ECM uses default throttle
position value based on mass air
flow and engine speed.

CIRCUIT DESCRIPTION
The TPS circuit provides a voltage signal that changes
relative to throttle blade angle. The signal voltage will
vary from below 0.6 volts at closed throttle to about 4.5
volts at wide open throttle (WOT).
The TPS signal is used by the Engine Control Module
(ECM) for fuel control and many of the ECM-controlled
outputs.

DIAGNOSTIC AIDS
Check for the following conditions:
 Poor connection at ECM – Inspect harness
connectors for backed-out terminals, imprope
r
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 throttle position display on the Tech 2 while
moving connectors and wiring harnesses related to
the TPS. A change in the display will indicate the
location of the fault.
If DTC P0122 cannot be duplicated, the information
included in the Failure Records data can be useful in
determining vehicle mileage since the DTC was last set.

6E-188 3.5L ENGINE DRIVEABILITY AND EMISSIONS
DIAGNOSTIC TROUBLE CODE (DTC) P0123 (FLASH CODE 21) THROTTLE
POSITION SENSOR CIRCUIT HIGH INPUT



RUW46EMF000101

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)
21 P0123 A Throttle Position
Sensor High Input TPS output voltage is more than 4.56V. The ECM uses default throttle
position value based on mass air
flow and engine speed.

CIRCUIT DESCRIPTION
The TPS circuit provides a voltage signal that changes
relative to throttle blade angle. The signal voltage will
vary from about 0.6 volts at closed throttle to about 4.5
volts at wide open throttle (WOT).
The TPS signal is one of the most important inputs
used by the Engine Control Module (ECM) for fuel
control and many of the ECM-controlled outputs.
DIAGNOSTIC AIDS
Check for the following conditions:
 Poor connection at ECM – Inspect harness
connectors for backed-out terminals, imprope
r
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 TPS display on the Tech 2 while moving
connectors and wiring harnesses related to the TP
sensor. A change in the display will indicate the
location of the fault.
 Faulty TPS –With the ignition key “ON," engine
“OFF," observe the TPS display on the Tech 2 while
slowly depressing the accelerator to wide open
throttle. If a voltage over 4.56 volts is seen at any
point in normal accelerator travel, replace the TPS.
If DTC P0123 cannot be duplicated, the information
included in the Failure Records data can be useful in
determining vehicle mileage since the DTC was last set.

3.5L ENGINE DRIVEABILITY AND EMISSIONS 6E-235
CIRCUIT DESCRIPTION
The CKP reference signal is produced by the crankshaft
position (CKP) sensor. During one crankshaft
revolution, crankshaft pulses will be produced. The
Engine Control Module (ECM) uses the CKP reference
signal to calculate engine RPM and crankshaft position.
The ECM constantly monitors the number of pulses on
the CKP reference circuit and compares them to the
number of camshaft position (CMP) signal pulses being
received. If the ECM receives an incorrect number o
f
pulses on the CKP reference circuit, DTC P0336 will
set.

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.
Reviewing the Failure Records vehicle mileage since
the diagnostic test last failed may help determine ho
w
often the condition that caused the DTC to be set
occurs. This may assist in diagnosing the condition.

Diagnostic Trouble Code (DTC) P0336 (Flash Code 29) Crankshaft Position
Sensor Circuit Range/Performance (58X)
Diagnostic Trouble Code (DTC) P0337 (Flash Code 29) Crankshaft Position
Sensor Circuit No Signal (58X)

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 P0336 or P0337 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 P0336 or P0337 stored in this ignition
cycle?
- Go to Step 4 Refer to
Diagnostic Aids
and Go to Step 4
4
Check any accessory parts which may cause electric
interference or magnetic interference.
Was the problem found?
- Remove the
accessory parts
and verify repair Go to Step 5
5
Attempt to start the engine.
Does the engine start and continue to "Run"?
- Go to Step 6 Go to Step 7