check engine ISUZU TF SERIES 2004 Workshop Manual

3.5L ENGINE DRIVEABILITY AND EMISSIONS 6E -93





5.
After choosing the data, click the "Next" button.
6.
When all the necessary information is entered, the
"details" of software within the database that
match the entered data will appear fo
r
confirmation. Click the "Program" switch and then
download the new software onto Tech-2.
7. "Data Transfer" comes on display. The progress o
f
downloading will be displayed on the screen in the
form of bar graph.
8.
Upon finishing the data transfer, turn off the powe
r
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 "F1: Program ECU".
7.
While data is being transferred, "Programing 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 ove
r
again "Information Obtaining" and check to confirm
if the data has been correctly re-loaded.
10. Upon finishing confirmation, turn off the ignition o
f
the vehicle and then turn off the power of Tech-2,
removing from the vehicle.

3.5L ENGINE DRIVEABILITY AND EMISSIONS 6E -95

Breaker Box Connection Type A

1
5 2
3
4


Legend

(1)
Engine Control Module (ECM) (Under the harness
adaptoer)

(2)
Harness Adapter

(3)
Breaker Box


(4)
Digital Voltage Meter

(5)
ECM - Harness Adapter Disconnection



Breaker box connection type A, check for "open circuit"
and "short to ground circuit".

6E-96 3.5L ENGINE DRIVEABILITY AND EMISSIONS

Breaker Box Connection Type B



2
5 1
4 3


Legend

(1)
Engine Control Module (ECM) (Under the harness
adapter)

(2)
Harness Adapter

(3)
Breaker Box


(4)
Digital Voltage Meter

(5)
ECM - Harness Adapter Connection



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.

3.5L ENGINE DRIVEABILITY AND EMISSIONS 6E -97

ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK

RTW46EM F000401

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, improperl
y
formed or damaged terminals, poor terminal-to-wire
connection, 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 o
f
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.
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 onl
y
memory (EEPROM).

6E-98 3.5L ENGINE DRIVEABILITY AND EMISSIONS

On-Board Diagnostic (OBD) System Check

Step Action Value (s) Yes No
1
1. Ignition "On", engine "Off".
2. Check the "CHECK ENGINE" lamp (MIL).
Does the "CHECK ENGINE" lamp turn "On"?
- Go to Step 2
Go to No CHECK
ENGINE Lamp
2
1. Using the Tech 2, ignition "On" and engine "Off".
2. Attempt to display "Engine Data" with the Tech 2.
Does the Tech 2 display "Engine Data" and "O2
Sensor Data"?
- Go to Step 3
Go to Step 7

3
1. Using the Tech 2, ignition "On" and engine "Off".
2. Select the "Miscellaneous Test" and perform the
"Malfunction Indicator Lamp" in "Lamps".
3. Operate the Tech 2 in accordance with the Tech 2
instructions.
Does the "CHECK ENGINE" lamp turn "Off"?
- Go to Step 4
Go to CHECK
ENGINE LAMP
On Steady
4
Attempt to start the engine. Does the engine start and
continue to "Run"?
- Go to Step 5
Go to Engine
Cranks But Will
Not Run
5
1. Using the Tech 2, ignition "On" and engine "Off".
2. Select the "Read DTC In for By Priority" in
"Diagnostic Trouble Code".
Are any DTCs stored?
- Go to DTC Chart
Go to Step 6

6
Compare typical scan data values displayed on the
Tech 2 "Engine Data" and "O2 Sensor Data".
Are the displayed values within the range?
- Refer to
SYMPTOM
DIAGNOSIS Refer to
TYPICAL SCAN
DATA
7
Using 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?
V


B-58


-
Repair faulty
harness and
verify repair
Go to Step 8

3.5L ENGINE DRIVEABILITY AND EMISSIONS 6E -99

Step Action Value (s) Yes No
8
Using 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?





B-58


-
Repair faulty
harness and
verify repair
Go to Step 9

9
Using 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?


B-58
VV

Less than 1V Go to Step 10

Repair faulty
harness and
verify repair
10
Using 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 battery voltage?
V
B-58



-
Repair faulty
harness and
verify repair
Go to Step 11

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
-

3.5L ENGINE DRIVEABILITY AND EMISSIONS 6E -101

NO CHECK ENGINE LAMP (MIL)

RTW46EM F000401

CIRCUIT DESCRIPTION
The “Check Engine" lamp (MIL) should always be
illuminated and steady with the ignition “ON" and the
engine stopped. Ignition feed voltage is supplied to the
MIL bulb through the meter fuse. The Engine Control
Module (ECM) turns the MIL “ON" by grounding the MIL
driver circuit.

DIAGNOSTIC AIDS
An intermittent MIL may be cased by a poor connection,
rubbed-through wire insulation, or a wire broken inside
the insulation. Check for the following items:

Inspect the ECM harness and connections fo
r
improper mating, broken locks, improperly formed o
r
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 MIL 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-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

6E-104 3.5L ENGINE DRIVEABILITY AND EMISSIONS

CHECK ENGINE LAMP (MIL) “ON" STEADY

RTW46EM F000401

CIRCUIT DESCRIPTION
The “Check Engine" lamp (MIL) should always be
illuminated and steady with ignition “ON" and the engine
stopped. Ignition feed voltage is supplied directly to the
MIL indicator. The Engine Control Module (ECM) turns
the MIL “ON" by grounding the MIL driver circuit.
The MIL should not remain “ON" with the engine
running and no DTC(s) set. A steady MIL with the
engine running and no DTC(s) suggests a short to
ground in the MIL driver 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 the following items:

Poor connection or damaged harness – Inspect the
ECM harness and connectors for improper mating,
broken locks, improperly formed or damaged
terminals, poor terminal-to-wire connection, and
damaged harness.