check engine ISUZU TF SERIES 2004 Workshop Manual

6E–100 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS
2. Demand of Data
1. Connect Tech-2 to the vehicle. When activated by
turning on the power of Tech-2, push the “Enter”
switch.
2. Turn on the ignition switch (without starting the
engine)
3. In the main menu of Diagnostic Tester, push “F1:
Service Programming System (SPS)”.
4. Push “F0: Request Info” of Tech-2.5. Where vehicle data has been already saved in Tech
2, the ex isting data come on display. In this
instance, as Tech-2 starts asking whether to keep
the data or to continue obtaining anew data from the
control unit, choose either of them
6. If you select “continue”, you have to select “Model
Year”, “Vehicle Type”.
7. After that. then push button and turn Ignition switch
tuned on, off, on following Tech-2 display. Tech-2
will read information from controller after this
procedure.
8. During obtaining information, Tech-2 is receiving
information from the control unit ECM and TCM (A/T
only) at the same time. With VIN not being
programmed into the new control unit at the time of
shipment, "obtaining information" is not complete
(because the vehicle model, engine model and
model year are specified from VIN). For the
procedure get additional information on vehicles,
instruction will be provided in dialog form, when
TIS2000 is in operation.
9. Following instructions by Tech-2, push the “Ex it”
switch of Tech-2, turn off the ignition of the vehicle
and turn off the power of Tech-2, thereby removing
from the vehicle.3. Data Exchange
1. Connect Tech-2 to P/C, turn on the power and click
the “Next” button of P/C.
2. Check VIN of the vehicle and choose “Next”.
3. Select “System Type” for required control unit.
Engine (Programming for ECM or PCM)
Transmission (Programming for TCM)
4. When a lack of data is asked from among the
following menu, enter accordingly.
Select following Menu
Model Year
Model
Engine type
Transmission type
Destination code (vehicles for general export)*1
Immobilizer
Etc.
* 1: How to read the destination code
Destination code can be read from ID Plate affix ed on
vehicles, while on VIN plate the destination code is
described at the right-hand edge of Body Type line. In
the figure, the destination code can be read as "RR3"
(Australia).

4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E–101
5. After choosing the data, click the “Nex t” button.
6. When all the necessary information is entered, the
“details” of software within the database that match
the entered data will appear for confirmation. Click
the “Program” switch and then download the new
software onto Tech-2.
7.“Data Transfer” comes on display. The progress of
downloading will be displayed on the screen in the
form of bar graph.
8. Upon finishing the data transfer, turn off the power
of Tech-2, removing from P/C.4. Programming of ECM
1. Check to see if batteries are fully charged, while
ABS connectors shall be removed from the vehicle.
2. Connect Tech-2 to Vehicle Diagnostic Connectors.
3. Turn on the power of Tech-2 and the title screen
comes on display.
4. Turn on the ignition (without allowing the engine to
start)
5. On the title screen of Tech-2, push the “Enter”
button.
6. Choose “F1: Service Programming System” on the
main screen and then choose “Fl: Program ECU”.
7. While data is being transferred, “Programming in
Progress” will be displayed on the Tech-2 screen.
8. Upon finishing the data transfer, Tech-2 will display
“Reprogramming Was Successful”. Push the “Exit”
button to bring program to completion
9. Following “Procedure 2: Demand of Data”, try over
again “Information Obtaining” and check to confirm
if the data has been correctly re-loaded.
10. Upon finishing confirmation, turn off the ignition of
the vehicle and then turn off the power of Tech-2,
removing from the vehicle.

4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E–103
Breaker Box Connection Type A
Breaker box connection type A, check for “open circuit”
and “short to ground circuit”.
342
51
(1) Engine Control Module (ECM)
(2) Harness Adapter
(3) Breaker Box(4) Digital Voltage Meter
(5) ECM - Harness Adapter Disconnection

6E–104 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS
Breaker Box Connection Type B
Breaker box connection type B, check for “short to
power supply circuit” and “power, signal voltage check”
between the engine control module (ECM) and
electrical components.


(1) Engine Control Module (ECM)
(2) Harness Adapter
(3) Breaker Box(4) Digital Voltage Meter
(5) ECM - Harness Adapter Connection

4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E–105
ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK
Circuit Description
The on-board diagnostic system check is the starting
point for any driveability complaint diagnosis. Before
using this procedure, perform a careful visual/physical
check of the ECM and engine grounds for cleanliness
and tightness.
The on-board diagnostic system check is an organized
approach to identifying a problem created by an
electronic engine control system malfunction.
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 connections or a
damaged harness. Inspect the ECM harness and
connector for improper mating, broken locks, improperly
formed or damaged terminals, poor terminal-to-wireconnection, and damaged harness.
Test Description
Number(s) below refer the step number(s) on the
Diagnostic Chart:
1. The Check Engine Lamp (MIL) should be ON steady
with the ignition “On”, engine “Off”. If not, “No Check
Engine Lamp (MIL)” chart should be used to isolate the
malfunction.
2. Checks the Class 2 data circuit and ensures that the
ECM is able to transmit serial data.
3. This test ensures that the ECM is capable of
controlling the Check Engine Lamp (MIL) and the Check
Engine Lamp (MIL) driver circuit is not shorted to
ground circuit.
4. If the engine will not start, “Engine Cranks But Will
Not Run” chart should be used to diagnose the fault.

6E–106 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS
6. The Tech2 parameters which is not within the typical
range may help to isolate the area which is causing the
problem.12. This vehicle is equipped with ECM which utilizes an
electrically erasable programmable read only memory
(EEPROM).
On-Board Diagnostic (OBD) System Check
Step Action Value(s) Yes No
11. Ignition “On”, engine “Off”.
2. Check the “CHECK ENGINE” lamp (MIL).
Does the “CHECK ENGINE” lamp turn “On”?—Go to Step 2Go to No
CHECK
ENGINE Lamp
21. Using the Tech 2, ignition “On” and engine “Off”.
2. Attempt to display “Data Display” with the Tech 2.
Does the Tech 2 display engine data? —Go to Step 3Go to Step 7
31. Using the Tech 2, ignition “On” and engine “Off”.
2. Select the “Miscellaneous Test” and perform the
“Check Light” in “Lamps”.
3. Operate the Tech 2 in accordance with the Tech 2
instructions.
Does the “CHECK ENGINE” lamp turn “Off”? —Go to Step 4Go to CHECK
ENGINE LAMP
On Steady
4Attempt to start the engine.
Does the engine start and continue to “Run”?
—Go to Step 5Go to Engine
Cranks But Will
Not Run
51. Using the Tech 2, ignition “On” and engine “Off”.
2. Select the “Read DTC Infor As Stored By ECU” in
“Diagnostic Trouble Code”.
3. Are any DTCs stored?—Go to DTC
ChartGo to Step 6
6Compare typical scan data values displayed on the
Te c h 2 “Data Display”.
Are the displayed values within the range?—Refer to
SYMPTOM
DIAGNOSISRefer to
TYPICAL
SCAN DATA
7Using the DVM and check the data link connector
power supply circuit.
1. Ignition “Off”, engine “Off”.
2. Check the circuit for open circuit.
Was the problem found?
—Repair faulty
harness and
verify repair Go to Step 8
V
B-58

4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E–107
8Using the DVM and check the data link connector
ground circuit.
1. Ignition “Off”, engine “Off”.
2. Check the circuit for open circuit.
Was the problem found?
—Repair faulty
harness and
verify repair Go to Step 9
9Using the DVM and check the data link connector
ground circuit.
1. Ignition “On”, engine “Off”.
2. Check the circuit for short to power supply circuit.
Was the DVM indicated specified value?
Less than 1V Go to Step 10Repair faulty
harness and
verify repair
10Using the DVM and check the data link connector
communication circuit.
1. Ignition “On”, engine “Off”.
2. Check the circuit for short to power supply circuit.
Was the DVM indicated fix ed battery voltage?
—Repair faulty
harness and
verify repair Go to Step 11 Step Action Value(s) Yes No
5 4
B-58
VV
5 4
B-58
V
6
B-58

6E–108 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS
11Using 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?
—Repair faulty
harness and
verify repair Go to Step 12
12Is 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
13Replace 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.—Veri fy repai r— Step Action Value(s) Yes No





C-56
B-58

4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E–109
NO CHECK ENGINE LAMP (MIL)
Circuit Description
The check engine lamp should be illuminated and
steady for about five seconds with the ignition “ON” and
the engine stopped. Ignition feed voltage is supplied to
the check engine lamp bulb through the meter fuse.
The Engine Control Module (ECM) turns the check
engine lamp “ON” by grounding the check engine lamp
driver circuit.
Diagnostic Aids
An intermittent check engine lamp may be cased by a
poor connection, rubbed-through wire insulation, or awire broken inside the insulation. Check for the
following items:
Inspect the ECM harness and connections for
improper mating, broken locks, improperly formed or
damaged terminals, poor terminal-to-wire connection,
and damaged harness.
If the engine runs OK, check for a faulty light bulb, an
open in the check engine lamp driver circuit, or an
open in the instrument cluster ignition feed.
If the engine cranks but will not run, check for an
open ECM ignition or battery feed, or a poor ECM to
engine ground.

6E–110 4JA1/4JH1 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?
10-14.5V Go to Step 5Go 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?
—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
V
42
C-56
42
17
B-24 C-56