Isuzu N-Series. Manual - part 798

Engine Control System (4JH1) 6E-243

Repair Instructions

Engine Control Module (ECM)
Replacement

Engine Control Module (ECM) Replacement
Procedure
Important:
If the ECM is to be replaced the following programmed
contents MUST be reprogrammed into the new ECM.

• Vehicle identification number (VIN).
• Latest software/calibrations if released. Refer to

Service Programming System (SPS) Description
and Service Programming System (SPS) (Remote
Procedure) or Service Programming System
(SPS) (Pass-Thru Procedure) in this section.

Removal Procedure

1. Disconnect the negative battery cable.
2. Remove the instrument cover.
3. Remove a bolt from the ECM bracket.
4. Disconnect the two connectors from the ECM.

Legend

1. ECM
2. Bracket

Installation Procedure

1. Connect the two connectors to the ECM.
2. Put on the ECM to the bracket and tighten by a

bolt.

3. Refit the instrument cover by four screws.
4. Connect the negative battery cable.

Vehicle Identification Number (VIN) Programming
Procedure
Important:
If the ECM from another vehicle is installed, VIN is not
programmed by the Tech 2. Use the SPS to change
the original VIN. Refer to Service Programming
System (SPS) Description and Service Programming
System (SPS) (Remote Procedure) or Service
Programming System (SPS) (Pass-Thru Procedure) in
this section.

Important:
If an updated software/calibrations is released, DO
NOT program the VIN now. The VIN is programmed at
SPS procedure. Refer to Service Programming
System (SPS) Description and Service Programming
System (SPS) (Remote Procedure) or Service
Programming System (SPS) (Pass-Thru Procedure) in
this section.

1. Connect the Tech 2 to the vehicle DLC, with the

engine and the Tech 2 OFF.

2. Turn ON the Tech 2.
3. Select Diagnostic > appropriate vehicle

identification > Powertrain > 4JH1-TC >
Programming > Program VIN.

4. Input correct VIN reading from stamped VIN or

affixed VIN plate on the vehicle.

5. Select Lock ECU and lock the programmed VIN.

Service Programming System (SPS)
Description

The service programming system (SPS) allows a
technician to program a control module through the
data link connector (DLC). The information transfer
circuit that is used at the DLC is the same serial data
circuit used be the Tech 2 for retrieving diagnostic
trouble codes (DTCs), displaying data, clearing DTCs
etc. This procedure offers the ability to install software/
calibrations matched to a particular vehicle.
Most control modules have two types of memory. The
software/calibrations reside in the flash memory. The
two types of memory are listed below:

• Electrically Erasable Programmable Read Only

Memory (EEPROM).
This type of memory allows selected portions of
memory to be programmed while other portions
remain unchanged.
Certain learned values reside in the EEPROM,
such as:

- The vehicle identification number (VIN)
- The software/calibrations identification

numbers

- The control module security information

N6A3892E

6E-244 Engine Control System (4JH1)

• Flash Read Only Memory-Flash MemoryFlash

memory has increased memory storage capacity.
During programming, all information within this
type of memory is erased, and then replaced with
entirely new information.

Service Programming Methods
The two methods of programming an engine control
module (ECM) are listed below:

• Remote Programming
• Pass Thru Programming

For information on programming an ECM using one of
the methods listed above, refer to Service
Programming System (SPS) (Remote Procedure) or
Service Programming System (SPS) (Pass-Thru
Procedure).

Before Programming a Control Module
Important:
DO NOT program an existing ECM with the identical
software/calibration package. This procedure is not a
short cut to correct the driveability condition. This is an
ineffective repair. An ECM should only be programmed
when the following occurs:

• When a service procedure instructs you to replace

the ECM. When the ECM from another vehicle is
installed, VIN must be changed. And change
vehicle information as necessary such as type of
transmission.

• An updated software/calibrations is released.

Ensure that the following conditions are met before
programming an ECM:

• The Tech 2 PCMCIA card is programmed with the

latest software.

• The TIS 2000 is installed with the latest software.
• The hardware key is plugged into the computer

port.

• Vehicle system voltage:

- There are no charging system concerns. All

charging system concerns must be repaired
before programming the ECM.

- The battery voltage is greater than 12 volts but

less than 16 volts. The battery must be fully
charged before programming the ECM.

- A battery charger is NOT connected to the

vehicles battery. Incorrect system voltage or
voltage fluctuations from a battery charger may
cause programming failure or ECM damage.

- Turn OFF or disable any system that may put a

load on the vehicles battery. Turn OFF or
disable systems such as:

◊ Heating, ventilation, and air conditioning

(HVAC) systems

◊ Headlights
◊ Room lights
◊ Accessory equipment

• The ignition switch is in the proper position. The

Tech 2 prompts you to turn ON the ignition, with
the engine OFF. DO NOT change the position of
the ignition switch during the programming
procedure unless instructed to do so.

• All tool connections are secure:

- The RS-232 cable
- The connection at the DLC
- The voltage supply circuits

• DO NOT disturb the tool harnesses while

programming. If an interruption occurs during the
programming procedure, programming failure or
ECM damage may occur.

• If you are performing the Pass-Thru programming

procedure using a notebook computer without the
power cord, ensure that the internal battery is fully
charged.

Service Programming System (SPS)
(Remote Procedure)

The Remote Service Programming System (SPS)
method is a three-step process that involves the
following procedures:

1. Connecting the Tech 2 to the vehicle and obtaining

the information from the engine control module
(ECM).

2. Connecting the Tech 2 to the terminal and

downloading a new calibration file from the
terminal into the Tech 2 memory.

3. Reconnecting the Tech 2 to the vehicle and

uploading the new calibration file into the ECM.

Performing the Remote Procedure

1. Connect the Tech 2 to the vehicle and obtain the

ECM information using the following procedure:

Important:
Ensure the ECM is installed in the vehicle and the
battery is fully charged before programming.

a. Connect the Tech 2 to the vehicle data link

connector (DLC), with the engine and the Tech
2 OFF.

b. Turn ON the Tech 2.
c. Press Enter at the title screen.
d. Turn ON the ignition, with the engine OFF.
e. Select Service Programming System at the

Main Menu.

f. Select Request Info.

Engine Control System (4JH1) 6E-245

g. If there is already stored in the Tech 2, the

existing data is displayed on the screen. The
Tech 2 asks user to keep existing data Keep
Data or Continue to request new vehicle
information from the ECM. If there is no data in
the Tech 2, it will immediately start vehicle
identification.

h. Enter the vehicle description by following the

on-screen instructions based on stamped VIN
or affixed VIN plate on the vehicle.

i. During obtaining information, the Tech 2 is

receiving information from any modules at the
same time. But only ECM information is
displayed on the screen.

j. Turn OFF all accessories and select Continue.
k. Verify that the correct VIN is entered on the

Tech 2. If the VIN is incorrect, write down the
correct VIN.

2. Turn OFF the Tech 2.
3. Disconnect the Tech 2 from the vehicle.
4. Turn OFF the ignition.
5. Transfer the data from the terminal to the Tech 2

using the following procedure:

Important:
The TIS supports service programming with the Tech 2
scan tool only.

a. Connect the Tech 2 to the terminal.
b. Launch the TIS application at the terminal.
c. Select the Service Programming System at the

main screen.

d. Highlight the following information on the Select

Diagnostic Tool and Programming Process
screen:

• Select Diagnostic Tool-Select Tech 2.
• Select Programming Process-Identify

whether an existing ECM is being
reprogrammed or an ECM is being replaced
with a new one.

• Select ECU Location-Select Vehicle.

e. Select Next.
f. Verify the connections on the Preparing for

Communication screen and select Next.

g. Verify the VIN on the Validate Vehicle

Identification Number (VIN) screen and select
Next.

Important:
If the ECM is replaced to new one, VIN does not
displayed. Input correct VIN reading from stamped VIN
or affixed VIN plate on the vehicle. If the ECM from
another vehicle is installed, input correct VIN by same
way.

h. Highlight Engine on the System Type screen

and select Next, if requested.

i. Complete the following information based on

the service ID plate on the Validate Vehicle
Data screen until Next is highlighted:

• Model
• Model Year
• Engine
• Type of Transmission
• Destination Code

j. Select Next.
k. Verify your selection on the Summary screen.

Important:
Refer to Service Bulletins before service programming
is performed if the bulletins are listed along with the
calibration files.

Important:
Select Cancel if you receive a message stating that the
calibration selected is already the current calibration in
the ECM and reprogramming with the same download
is not allowed.

l. Select Reprog.
m. The Transfer Data screen will appear until the

progress bar reaches 100%.

6. Close the application and return to the TIS

application selection screen after the download is
complete.

7. Turn OFF the Tech 2.
8. Disconnect the Tech 2 from the terminal.
9. Transfer the data from the Tech 2 to the ECM using

the following procedure:
a. Connect the Tech 2 to the vehicle DLC, with the

engine and the Tech 2 OFF.

b. Turn ON the Tech 2.
c. Press Enter at the Title screen.
d. Turn ON the ignition, with the engine OFF.
e. Select Service Programming System.
f. Select the Program ECU on the Tech 2.
g. Follow the on-screen instructions and select

Continue.

h. Programming in Process will appear until the

progress bar reaches 100%.

Important:
The vehicle fitted with automatic transmission, Check
Trans lamp may blink while programming the ECM
since communication between the ECM and TCM is
interrupted. Clear DTC in any module after
programming.

i. Select Continue and exit the program after the

Tech 2 displays Programming Was Successful.

10. Turn OFF the ignition.

11. Turn OFF the Tech 2.

12. Disconnect the Tech 2 from the vehicle.

6E-246 Engine Control System (4JH1)

Service Programming System (SPS) (Pass-
Thru Procedure)

Pass-Thru programming allows the Tech 2 to remain
connected to the terminal and to the vehicle throughout
the programming process. The vehicle must be in
close proximity to the terminal while using Pass-Thru.

Important:
The TIS supports service programming with the Tech 2
scan tool only.

1. Launch the TIS application at the terminal

application at the terminal.

2. Select the Service Programming System at the

main screen.

3. Highlight the following information on the Select

Diagnostic Tool and Programming Process screen:

• Select Diagnostic Tool-Select Pass-Thru
• Select Programming Process-Identify whether

as existing engine control module (ECM) is
being reprogrammed or an ECM is being
replaced with a new one.

• Select ECU Location-Select Vehicle.

4. Select Next.
5. Complete all vehicle data on the Preparing for

Communication/Determine Vehicle screen until
Next is highlighted.

6. Select Next.
7. Follow the instruction on the Preparing for

Communication screen.

Important:
In order to reduce the potential for signal loss, the RS-
232 cable should not be more than 25 feet long.

8. Select Next.
9. Verify the VIN on the Validate Vehicle Identification

Number (VIN) screen and select Next.

10. Highlight Engine on the System Type screen and

select Next, if requested.

11. Complete the following information based on the

service ID plate on the Validate Vehicle Data
screen until Next is highlighted:

• Model
• Model Year
• Engine
• Type of Transmission
• Destination Code

12. Select Next.
13. Verify your selection on the Summary screen.

Important:
Refer to Service Bulletins before service programming
is performed if the bulletins are listed along with the
calibration files.

Important:
Select Cancel if you receive a message stating that the
calibration selected is already the current calibration in
the Tech 2 and reprogramming with the same
download is not allowed.

14. Select Reprog.
15. The Transfer Data screen will appear until the

progress bar reaches 100%.

16. Select Close on the Programming Complete

screen.

17. Turn OFF the Tech 2.
18. Disconnect the Tech 2 from the vehicle.

Accelerator Pedal Position (APP) Sensor
Replacement

Removal Procedure

1. Disconnect the negative battery cable.
2. Disconnect the APP and idle switch connector.
3. Remove the accelerator pedal assembly from the

bracket.

4. Loosen two nuts and remove APP from the

accelerator pedal bracket.

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