display ISUZU TF SERIES 2004 Workshop Manual

3.5L ENGINE DRIVEABILITY AND EMISSIONS 6E-217
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)
P0172 B O2 Sensor System Too
Rich (Bank 1) 45
P0175 B O2 Sensor System Too
Rich (Bank 2) 1. No DTC relating to MAF sensor, IAT sensor, ECT sensor,
TPS, CMP sensor, CKP sensor, VSS, injector control
circuit, ignition control circuit, O2 sensor circuit low voltage
& high voltage (bank 1 & 2) and O2 sensor circuit no
activity (bank 1 & 2).
2. Engine speed is more than 600rpm.
3. Intake air temperature is more than 50
C.
4. Engine coolant temperature is between 35
C and 120
C.
5. Engine load is more than 20%.
6. EVAP purge solenoid valve on-duty is below 100%.
7. Air-fuel ratio correction volume is below 50% for 20
seconds. No fail-safe function.


CIRCUIT DESCRIPTION
To provide the best possible combination of driveability,
fuel economy, and emission control, a “closed loop"
air/fuel metering system is used. While in “closed loop,"
the Engine Control Module (ECM) monitors the heated
oxygen sensors (HO2S) signals and adjusts fuel
delivery based upon the HO2S signal voltages.
A
change made to fuel delivery will be indicated by the
long and short term fuel trim values which can be
monitored with a Tech 2. Ideal fuel trim values are
around 0%; if the HO2S signals are indicating a lean
condition the ECM will add fuel, resulting in fuel trim
values above 0%. If a rich condition is detected, the fuel
trim values will be below 0%, indicating that the ECM is
reducing the amount of fuel delivered. If an excessively
rich condition is detected on Bank 1, the ECM will se
t
DTC P0172 or P0175.
The ECM's maximum authority to control long term fuel
trim allows a range between –15% (automatic
transmission) or –12 (manual transmission) and +20%.
The ECM's maximum authority to control short term fuel
trim allows a range between –11% and +20%. The ECM
monitors fuel trim under various engine speed/load fuel
trim cells before determining the status of the fuel trim
diagnostic.

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 HO2S display on the Tech 2 while moving
connectors and wiring harnesses related to the
engine harness. A change in the display will indicate
the location of the fault.

6E-218 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P0172 (Flash Code 45) O2 Sensor System Too
Rich (Bank 1)
Diagnostic Trouble Code (DTC) P0175 (Flash Code 44) O2 Sensor System Too
Rich (Bank 2)


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 P0172 or P0175 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 P0172 or P0175 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 "On".
2. Monitor the "Mass Air Flow" in the data display.
Does the Tech 2 indicate correct "Mass Air Flow" as
shown in the following graph, when engine speed is
increasing little by little?
Characteris tic of MAF Sens or -Ref erence (No Engine Load)-
0 5 10 15 20 25 30 35 40 45 50
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
Eng i ne Speed ( r pm) ( T ech2 R eadi ng )
Mass Air Flow (g/s)
( T ec h2 R eadi ng)
- Go to Step 6 Go to Step 5
5
Remove the MAF & IAT sensor assembly and check
for the following conditions.

Objects blocking the air cleaner.

Objects blocking the MAF sensor.

Objects blocking the throttle valve.

Vacuum leaking at intake duct.

Vacuum leaking at throttle body.
If a problem is found, repair as necessary.
Was the problem found?
- Verify repair Refer to DTC
P0101 and Go to
Step 6

3.5L ENGINE DRIVEABILITY AND EMISSIONS 6E-219
Step Action Value (s) Yes No
6
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 8 Go to Step 7
7
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%.
Is the action complete?
- Verify repair -
8
Check for the following conditions.

Objects blocking the throttle valve.

Vacuum leaking at throttle body.
If a problem is found, repair as necessary.
Was the problem found?
- Verify repair Refer to DTC
P0121 and Go to
Step 9
9
1. Using the Tech 2, ignition "On" and engine "On".
2. Select the "Miscellaneous Test" and perform the
"IAC Control" in the "IAC System".
3. Operate the Tech 2 in accrodance with procedure.
Was the engine speed changed, when the IAC Valve
is operating step by step?
-
Go to Step 11
Go to Step 10
10
Check for the following conditions.

Objects blocking the IAC Valve.

Objects blocking the throttle valve.

Vacuum leaking at throttle body.
If a problem is found, repair as necessary.
Was the problem found?
- Verify repair Refer to DTC
P1508/P1509
and Go to Step
11
11
Check for injector for the affected bank.
Refer to 6E-106 "Injector Coil Test & Injector Balance
Test Procedure".
Was the injector operation correct?
- Go to Step 12 Refer to Injector
Coil Test &
Injector Balance
Test Procedure
12
Check for fuel pressure.
Refer to 6E-116 "Fuel System Diagnosis".
Was the fuel pressure correct?
- Go to Step 13 Refer to Fuel
System
Diagnosis
13
Replace the O2 sensor for the affected bank.
Was the problem solved?
- Verify repair Go to Step 14
14
Is the ECM programmed with the latest software
release?
If not, download the latest software to the ECM using
the "SPS (Service Programming System)".
Was the problem solved?
- Verify repair Go to Step 15

3.5L ENGINE DRIVEABILITY AND EMISSIONS 6E-223
Diagnostic Trouble Code (DTC) P1171 (Flash Code 44) Fuel Supply System
Lean During Power Enrichment (Bank 1)
Diagnostic Trouble Code (DTC) P1172 (Flash Code 44) Fuel Supply System
Lean During Power Enrichment (Bank 2)
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 P1171 or P1172 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 P1171 or P1172 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 "On".
2. Monitor the "Mass Air Flow" in the data display.
Does the Tech 2 indicate correct "Mass Air Flow" as
shown in the following graph, when engine speed is
increasing little by little?
Characteris tic of MAF Sens or -Ref erence (No Engine Load)-
0 5 10 15 20 25 30 35 40 45 50
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
Eng i ne Speed ( r pm) ( T ech2 R eadi ng )
Mass Air Flow (g/s)
( T ec h2 R eadi ng)
- Go to Step 6 Go to Step 5
5
Remove the MAF & IAT sensor assembly and check
for the following conditions.

Objects blocking the air cleaner.

Objects blocking the MAF sensor.

Objects blocking the throttle valve.

Vacuum leaking at intake duct.

Vacuum leaking at throttle body.
If a problem is found, repair as necessary.
Was the problem found?
- Verify repair Refer to DTC
P0101 and Go to
Step 6

6E-224 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Step Action Value (s) Yes No
6
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 8 Go to Step 7
7
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%.
Is the action complete?
- Verify repair -
8
Check for the following conditions.

Objects blocking the throttle valve.

Vacuum leaking at throttle body.
If a problem is found, repair as necessary.
Was the problem found?
- Verify repair Refer to DTC
P0121 and Go to
Step 9
9
1. Using the Tech 2, ignition "On" and engine "On".
2. Select the "Miscellaneous Test" and perform the
"IAC Control" in the "IAC System".
3. Operate the Tech 2 in accrodance with procedure.
Was the engine speed changed, when the IAC Valve
is operating step by step?
-
Go to Step 10
Go to Step 10
10
Check for the following conditions.

Objects blocking the IAC Valve.

Objects blocking the throttle valve.

Vacuum leaking at throttle body.
If a problem is found, repair as necessary.
Was the problem found?
- Verify repair Refer to DTC
P1508/P1509
and Go to Step
11
11
Check for injector for the affected bank.
Refer to 6E-106 "Injector Coil Test & Injector Balance
Test Procedure".
Was the injector operation correct?
- Go to Step 12 Refer to Injector
Coil Test &
Injector Balance
Test Procedure
12
Check for fuel pressure.
Refer to 6E-116 "Fuel System Diagnosis".
Was the fuel pressure correct?
- Go to Step 13 Refer to Fuel
System
Diagnosis
13
Replace the O2 sensor for the affected bank.
Was the problem solved?
- Verify repair Go to Step 14
14
Is the ECM programmed with the latest software
release?
If not, download the latest software to the ECM using
the "SPS (Service Programming System)".
Was the problem solved?
- Verify repair Go to Step 15

6E-250 3.5L ENGINE DRIVEABILITY AND EMISSIONS

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)
P0351 A Ignition 1 Control
Circuit
P0352 A Ignition 2 Control
Circuit
P0353 A Ignition 3 Control
Circuit
P0354 A Ignition 4 Control
Circuit
P0355 A Ignition 5 Control
Circuit
42
P0356 A Ignition 6 Control
Circuit 1. No DTC relating to CMP sensor and CKP sensor.
2. Engine speed is between 250rpm and 850 rpm.
3. 10 ignition signals are not detected consecutively. Fuel cut is operated more than
2000rpm.

CIRCUIT DESCRIPTION
The Engine Control Module's (ECM) control circuit 1
provides a zero-volt or a 5-volt output signal to the
ignition coil. The normal voltage on the circuit is zero
volts. When the ignition coil receives the 5-volt signal
from the ECM, it provides a ground path for the B+
supply to the primary side of the number 1 ignition coil.
When the ECM shuts off the 5 volts to the ignition coil,
the ignition coil turns “OFF." This causes the ignition coil
primary magnetic field to collapse, producing a voltage
in the secondary coil which fires the spark plug.
The circuit between the ECM and ignition coil is
monitored for an open circuit, short to voltage, and shor
t
to ground. When the ECM detects a problem on ignition
control circuit, it will set a DTC P0351, P0352, P0353,
P0354, P0355 or P0356.

DIAGNOSTIC AIDS
Check for the following conditions:
 Poor connection at ECM – Inspect the harness
connectors for backed-out terminals, imprope
r
mating, broken locks, improperly formed or damaged
terminals, and poor terminal-to-wire connections.
 Damaged harness –Inspect the wiring harness fo
r
damage. If the harness appears to be OK, observe
the Tech 2 display related to DTC P0351 or P0352,
P0353, P0354, P0355 or P0356 while moving the
connector and wiring related to the ignition system.
A
change in the display will indicate the location of the
fault.
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.

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