service ISUZU TF SERIES 2004 Workshop Manual

6E-100 3.5L ENGINE DRIVEABILITY AND EMISSIONS

Step Action Value (s) Yes No
11
Using the DVM and check the data link connector
communication circuit.
1. Ignition "Off", engine "Off".
2. Disconnect the ECM connector.
3. Check the circuit for open or short to ground circuit.
Was the problem found?






E-61(B)
B-58



-
Repair faulty
harness and
verify repair
Go to Step 12
12
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 13
13
Replace the ECM.
Is the action complete?
IMPORTANT:
The replacement ECM must be
programmed. Refer to section of the Service
Programming System (SPS) in this manual. Following
ECM programming, the Immobilizer system (if
equipped) must be linked to the ECM. Refer to section
11 “Immobilizer System-ECM replacement”
for the
ECM/Immobilizer linking procedure.
-
Verify repair
-

6E-102 3.5L ENGINE DRIVEABILITY AND EMISSIONS

No Check Engine Lamp (MIL)

Step
Action Value (s) Yes No
1
Check the meter fuse (15A). If the fuse is burnt out,
repair as necessary.
Was the problem found?
- Verify repair Go to Step 2

2
Using the DVM and check the "CHECK ENGINE"
lamp circuit.
1. Ignition "Off", engine "Off".
2. Disconnect the ECM connector.
3. Ignition "On".
4. Check the circuit for open circuit.
Was the DVM indicated specified value?
V
E-61(B)



10 – 14.5V
Go to Step 5

Go to Step 3

3
Check the "CHECK ENGINE" lamp bulb. If the bulb is
burnt out, repair as necessary.
Was the problem found?
- Verify repair Go to Step 4

4
Using the DVM and check the "CHECK ENGINE"
lamp circuit.
1. Ignition "Off", engine "Off".
2. Disconnect the meter connector and ECM
connector.
3. Check the circuit for open circuit.
Was the problem found?




E-61(B)
B-24


-
Verify repair
Go to Step 5

5
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 6

3.5L ENGINE DRIVEABILITY AND EMISSIONS 6E -103

Step
Action Value (s) Yes No
6
Replace the ECM.
Is the action complete?
IMPORTANT:
The replacement ECM must be
programmed. Refer to section of the Service
Programming System (SPS) in this manual. Following
ECM programming, the Immobilizer system (if
equipped) must be linked to the ECM. Refer to section
11 “Immobilizer System-ECM replacement”
for the
ECM/Immobilizer linking procedure.
-
Verify repair
-

3.5L ENGINE DRIVEABILITY AND EMISSIONS 6E -105

Check Engine Lamp (MIL) “ON" Steady

Step Action Value (s) Yes No
1
1. Ignition "Off", engine "Off".
2. Disconnect the ECM connector.
3. Ignition "On".
Was the "CHECK ENGINE" lamp turned on?
- Go to Step 2
Go to Step 4

2
Using the DVM and check the "CHECK ENGINE"
lamp circuit.
1. Ignition "Off", engine "Off".
2. Disconnect the meter connector and ECM
connector.
3. Check the circuit for short to ground circuit.
Was the problem found?


B-24



E-61(B)


- Verify repair Go to Step 3

3
Replace the meter assembly.
Is the action complete?
- Verify repair -
4
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 5
5
Replace the ECM.
Is the action complete?
IMPORTANT: The replacement ECM must be
programmed. Refer to section of the Service
Programming System (SPS) in this manual. Following
ECM programming, the Immobilizer system (if
equipped) must be linked to the ECM. Refer to section
11 “Immobilizer System-ECM replacement”
for the
ECM/Immobilizer linking procedure.
-
Verify repair
-

3.5L ENGINE DRIVEABILITY AND EMISSIONS 6E-115
Step Action Value (s) Yes No
13
Using the DVM and check the fuel pump ground
circuit.
1. Ignition "Off", engine "Off".
2. Disconnect the fuel pump connector.
3. Check the circuit for open circuit.
Was the DVM indicated specified value?
F-2





Continuity Go to Step 15 Go to Step 14
14
Repair the open circuit between the fuel pump and
body ground.
Is the action complete?
F-2
C-109


- Verify repair -
15
Replace the fuel pump.
Was the problem solved?
- Verify repair Go to Step 16
16
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 17
17
Replace the ECM.
Is the action complete?
IMPORTANT: The replacement ECM must be
programmed. Refer to section of the Service
Programming System (SPS) in this manual. Following
ECM programming, the immobilizer system (if
equipped) must be linked to the ECM. Refer to section
11 “Immobilizer System-ECM replacement” for the
ECM/Immobilizer linking procedure.
- Verify repair -

3.5L ENGINE DRIVEABILITY AND EMISSIONS 6E-117
CIRCUIT DESCRIPTION
When the ignition switch is turned “ON," the Engine
Control Module (ECM) will turn “ON" the in-tank fuel
pump. The in-tank fuel pump will remain “ON" as long
as the engine is cranking or running and the ECM is
receiving 58X crankshaft position pulses. If there are no
58X crankshaft position pulses, the ECM will turn the
in-tank fuel pump “OFF" 2 seconds after the ignition
switch is turned “ON" or 2 seconds after the engine
stops running.
The in-tank fuel pump is an electric pump within an
integral reservoir. The in-tank fuel pump supplies fuel
through an in-line fuel filter to the fuel rail assembly. The
fuel pump is designed to provide fuel at a pressure
above the pressure needed by the fuel injectors. A fuel
pressure regulator, attached to the fuel rail, keeps the
fuel available to the fuel injectors at a regulated
pressure. Unused fuel is returned to the fuel tank by a
separate fuel return line.
TEST DESCRIPTION
Number(s) below refer to the step number(s) on the
Diagnostic Chart.
2. Connect the fuel pressure gauge to the fuel feed line
as shown in the fuel system illustration. Wrap a shop
towel around the fuel pressure connection in order to
absorb any fuel leakage that may occur when
installing the fuel pressure gauge. With the ignition
switch “ON" and the fuel pump running, the fuel
pressure indicated by the fuel pressure gauge
should be 333-376 kPa (3.4-3.8 kg/cm
2 / 48-55 psi).
This pressure is controlled by the amount o
f
pressure the spring inside the fuel pressure regulator
can provide.
3. A fuel system that cannot maintain a constant fuel
pressure has a leak in one or more of the following
areas:
 The fuel pump check valve.
 The fuel pump flex line.
 The valve or valve seat within the fuel pressure
regulator.
 The fuel injector(s).
4. Fuel pressure that drops off during acceleration,
cruise, or hard cornering may case a lean condition.
A lean condition can cause a loss of power, surging,
or misfire. A lean condition can be diagnosed using
a Tech 1 Tech 2. If an extremely lean condition
occurs, the oxygen sensor(s) will stop toggling. The
oxygen sensor output voltage(s) will drop below 500
mV. Also, the fuel injector pulse width will increase.

Important: Make sure the fuel system is not operating
in the “Fuel Cut-Off Mode."
When the engine is at idle, the manifold pressure is
low (high vacuum). This low pressure (high vacuum)
is applied to the fuel pressure regulator diaphragm.
The low pressure (high vacuum) will offset the
pressure being applied to the fuel pressure regulato
r
diaphragm by the spring inside the fuel pressure
regulator. When this happens, the result is lower fuel
pressure. The fuel pressure at idle will vary slightly
as the barometric pressure changes, but the fuel
pressure at idle should always be less than the fuel
pressure noted in step 2 with the engine “OFF."
16.Check the spark plug associated with a particula
r
fuel injector for fouling or saturation in order to
determine if that particular fuel injector is leaking. I
f
checking the spark plug associated with a particular
fuel injector for fouling or saturation does no
t
determine that a particular fuel injector is leaking,
use the following procedure:
 Remove the fuel rail, but leave the fuel lines and
injectors connected to the fuel rail. Refer to Fue
l
Rail Assembly in On-Vehicle Service.
 Lift the fuel rail just enough to leave the fuel
injector nozzles in the fuel injector ports.
CAUTION: In order to reduce the risk of fire and
personal injury that may result from fuel spraying
on the engine, verify that the fuel rail is positioned
over the fuel injector ports and verify that the fuel
injector retaining clips are intact.
 Pressurize the fuel system by connecting a 10
amp fused jumper between B+ and the fuel pump
relay connector.

Visually and physically inspect the fuel injector
nozzles for leaks.
17. A rich condition may result from the fuel pressure
being above 376 kPa (55 psi). A rich condition may
cause a DTC P0132 or a DTC P0172 to set.
Driveability conditions associated with rich conditions
can include hard starting (followed by black smoke)
and a strong sulfur smell in the exhaust.
20.This test determines if the high fuel pressure is due
to a restricted fuel return line or if the high fuel
pressure is due to a faulty fuel pressure regulator.
21.A lean condition may result from fuel pressure belo
w
333 kPa (48 psi). A lean condition may cause a DTC
P0131 or a DTC P0171 to set. Driveability conditions
associated with lean conditions can include hard
starting (when the engine is cold ), hesitation, poo
r
driveability, lack of power, surging , and misfiring.

3.5L ENGINE DRIVEABILITY AND EMISSIONS 6E-129
Step Action Value (s) Yes No
28
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 29
29
Replace the ECM.
Is the action complete?
IMPORTANT: The replacement ECM must be
programmed. Refer to section of the Service
Programming System (SPS) in this manual. Following
ECM programming, the immobilizer system (if
equipped) must be linked to the ECM. Refer to section
11 “Immobilizer System-ECM replacement” for the
ECM/Immobilizer linking procedure.
- Verify repair -

6E-146 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 or 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 4 to 7 g/s at idle to around
25 to 40 g/s at maximum engine load. DTC P0101 will
be set if the signal from the MAF sensor does not match
a predicted value based on throttle position and engine
RPM.
DIAGNOSTIC AIDS
An intermittent may be caused by the following:
 Poor connections.
 Mis-routed harness.
 Rubbed through wire insulation.
 Broken wire inside the insulation.
Refer to Intermittents under service category
Symptoms.
Any un-metered air may cause this DTC to set. Check
for the following:
 The duct work at the MAF sensor for leaks.
 An engine vacuum leak.
 The PCV system for vacuum leaks.
 An incorrect PCV valve.
 The engine oil dip stick not fully seated.
 The engine oil fill cap loose or missing.


Diagnostic Trouble Code (DTC) P0101 (Flash Code 61)
Mass Air Flow Sensor 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 P0101 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 P0101 stored in this ignition cycle?
- Go to Step 4 Refer to
Diagnostic Aids
and Go to Step 4

6E-148 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Step Action Value (s) Yes No
8
Using the DVM and check the MAF sensor signal
circuit.
1. Ignition "Off", engine "Off".
2. Disconnect the MAF sensor connector.
3. Ignition "On".
4. Check the circuit for short to power supply circuit.
Was the DVM indicated specified value?
V

E-63


Less than 1V
Go to Step 9
Repair faulty
harness and
verify repair
9
Check any accessory parts which may cause electric
interference.
- Remove the
accessory parts
and verify repair
Go to Step 10
10
Check the shield wire for open or short circuit.
Was the problem found?
- Verify repair Go to Step 11
11
Substitute a known good MAF & IAT sensor assembly
and recheck.
Was the problem solved?
- Go to Step 12 Go to Step 13
12
Replace the MAF & IAT sensor assembly.
Is the action complete?
- Verify repair
13
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 14
14
Replace the ECM.
Is the action complete?
IMPORTANT: The replacement ECM must be
programmed. Refer to section of the Service
Programming System (SPS) in this manual. Following
ECM programming, the immobilizer system (if
equipped) must be linked to the ECM. Refer to section
11 “Immobilizer System-ECM replacement” for the
ECM/Immobilizer linking procedure.
- Verify repair -

6E-152 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Step Action Value (s) Yes No

Breaker box is not available:
1. Ignition "Off", engine "Off".
2. Disconnect the MAF sensor connector and ECM
connector.
3. Check the circuit for open, short to sensor ground
or short to ground circuit.
Was the problem found?
E-61(B)




E-63





- Repair faulty
harness and
verify repair Go to Step 7
7
Using the DVM and check the MAF sensor power
supply circuit.
1. Ignition "Off", engine "Off".
2. Disconnect the MAF sensor connector and ECM
main relay.
3. Check the circuit for open circuit.
Was the problem found?


X-13E-63





-
Repair faulty
harness and
verify repair
Go to Step 8
8
Substitute a known good MAF & IAT sensor assembly
and recheck.
Was the problem solved?
- Go to Step 9 Go to Step 10
9
Replace the MAF & IAT sensor assembly.
Is the action complete?
- Verify repair -
10
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 11