4jh1 ISUZU TF SERIES 2004 Workshop Manual

6E–316 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS
6 Using the DVM and check the neutral switch (inhibitor switch) power supply circuit.
1. Ignition “On”, engine “Off”.
2. Remove the neutral switch (inhibitor switch) connector from the switch.
3. Check the circuit for open circuit.
Was the DVM indicated specified value?
10-14.5V Go to Step 8Go to Step 7
7 Repair the open circuit between the “ECM fuse (10A)” and neutral switch (between the “Back Up fuse (15A)”
and inhibitor switch).
Is the action complete? — Verify repair —
8 Using the DVM and check the neutral switch (inhibitor switch) circuit.
Breaker box is available:
1. Ignition “Off”, engine “Off”.
2. Install the breaker box as type B. (ECM connected) Ref. Page 6E-104
3. Ignition “On”, engine “Off”.
4. Check the circuit for open or short to voltage circuit.
Was the DVM indicated specified value?
Breaker box is not available: 1. Ignition “On”, engine “Off”.
2. Back probe the DVM to the neutral switch (inhibitor switch) and check the circuit for open or
short to voltage circuit.
Was the DVM indicated specified value?
Neutral (P or
N): 10-14.5V Other than
neutral (P or
N): Less than
1V Go to Step 11 Fix ed at 10-
14.5V: Go to Step 9
Fix ed at less
than 1V: Go to
Step 10
Step Action Value(s) Yes No
V
E-12
M/T
V
3
E-51
A/T
E-687Br eak er Box




V
8
2
VV
E-11
E-51
M/T
A/T

4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E–317
9 Repair the short to voltage circuit between the neutral
switch connector (inhibitor switch connector) and
ECM.
Is the action complete?
—Verify repair—
10 Repair the open circuit between the neutral switch
connector (inhibitor switch connector) and ECM.
Is the action complete?
—Verify repair—
11 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 12
12 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— Step Action Value(s) Yes No
87
878 2
C-57
C-57M/T
A/TE-11
E-51
87
878 2
C-57
C-57M/T
A/TE-11
E-51

6E–318 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS
DIAGNOSTIC TROUBLE CODE (DTC) P1605 (SYMPTOM CODE C)
(FLASH CODE 55) SEED AND KEY FILE DESTROYED
DIAGNOSTIC TROUBLE CODE (DTC) P1605 (SYMPTOM CODE D)
(FLASH CODE 55) EEPROM DEFECT
DIAGNOSTIC TROUBLE CODE (DTC) P1605 (SYMPTOM CODE E)
(FLASH CODE 55) EEPROM DEFECT
Condition for setting the DTC and action taken when the DTC sets
Circuit Description & Diagnostic Aids
The ECM used in this vehicle utilizes an electrically
erasable & programmable read only memory
(EEPROM). The EEPROM contains program
information and the calibrations required for engine anddiagnostics operation.
If the ECM inside (IC, circuit, memory, etc,) failed, DTC
P1605 (Symptom Code C), P1605 (Symptom Code D)
or P1605 (Symptom Code E) will be stored.
Diagnostic Trouble Code (DTC) P1605 (Symptom Code C) (Flash Code 55)
Seed and Key File Destroyed
Diagnostic Trouble Code (DTC) P1605 (Symptom Code D) (Flash Code 55)
EEPROM Defect
Diagnostic Trouble Code (DTC) P1605 (Symptom Code E) (Flash Code 55)
EEPROM Defect
Flash
CodeCode Symptom
CodeMIL DTC Name DTC Setting Condition Fail-Safe (Back Up)
55 P1605 C ON Seed and Key File Destroyed Seed or key file in EEPROM
is destroyed.No fa il-sa fe fun ctio n.
D ON EEPROM Defe ct Write a nd re ad fro m the
EEPROM are fa iled during ini-
tialization of the ECM.ECM uses default values from
the EPROM.
E ON EEPROM Defe ct EEPROM checksum doe s no t
match with the read check
sum during initialization of the
ECM.
Step Action Value(s) Yes No
1Was the “On-Board Diagnostic (OBD) System Check”
performed?
—Go to Step 2Go 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 As Stored By ECU” in
“F0: Diagnostic Trouble Codes”.
Is the DTC P1605 (Symptom Code C), P1605
(Symptom Code D) or P1605 (Symptom Code E)
stored as “Present Failure”?—Go to Step 3Refer to
Diagnostic Aids
and Go to Step
3

4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E–319
3 1. Using the Tech 2, ignition “On” and engine “Off”.
2. Select “F1: Clear DTC Information” in “F0:
Diagnostic Trouble Codes” with the Tech 2 and
clear the DTC information.
3. Operate the vehicle and monitor the “F0: Read
DTC Infor As Stored By ECU” in the “F0:
Diagnostic Trouble Codes”.
Was the DTC P1605 (Symptom Code C), P1605
(Symptom Code D) or P1605 (Symptom Code E)
stored in this ignition cycle?—Go to Step 4Refer to
Diagnostic Aids
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— Step Action Value(s) Yes No

6E–320 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS
DIAGNOSTIC TROUBLE CODE (DTC) P1610 (SYMPTOM CODE A)
(FLASH CODE 56) SECURITY KEY AND SECURITY CODE NOT PROGRAMMED
Condition for setting the DTC and action taken when the DTC sets
Circuit Description
The ECM decides whether that is an abnormality in the
immobilizer control system. DTC P1610 (Symptom
Code A) is recorded when immobilizer function was not
programmed in the ECM.
Diagnostic Aids
Check for the following conditions:
Poor connection at ECM and immobilizer control unit-
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 for
damage. If the harness appears to be OK, observe
the DTC P1610 display on the Tech2 while moving
connectors and wiring harnesses.
Flash
CodeCode Symptom
CodeMIL DTC Name DTC Setting Condition Fail-Safe (Back Up)
56 P1610 A - Security Key and Security
Code not ProgrammedImmobilizer functions are not
programmed in the ECM.1. Engine does not start.
2. Check e ngine lamp fla sh.

4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E–321
Diagnostic Trouble Code (DTC) P1610 (Symptom Code A) (Flash Code 56)
Security Key and Security Code Not Programmed
Step Action Value(s) Yes No
1Was the “On-Board Diagnostic (OBD) System Check”
performed?
—Go to Step 2Go 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 As Stored By ECU” in
“F0: Diagnostic Trouble Codes”.
Is the DTC P1610 (Symptom Code A) stored as
“Present Failure”?—Go to Step 3Refer to
Diagnostic Aids
and Go to Step
3
3 1. Using the Tech 2, ignition “On” and engine “Off”.
2. Select “F1: Clear DTC Information” in “F0:
Diagnostic Trouble Codes” with the Tech 2 and
clear the DTC information.
3. Operate the vehicle and monitor the “F0: Read
DTC Infor As Stored By ECU” in the “F0:
Diagnostic Trouble Codes”.
Was the DTC P1610 (Symptom Code A) stored in this
ignition cycle?—Go to Step 4Refer to
Diagnostic Aids
and Go to Step
4
4 1. Using the Tech 2, ignition “On” and engine “Off”.
2. Select “Immobilizer” in the system selection menu
“Body”.
3. Select “Read DTC Info Ordered By Priority” in the
“Diagnostic Trouble Code”.
Was the any DTC's B0002 or B0009 stored in this
ignition cycle?—Refer to
“Immobilizer
Workshop
Manual” & Go
to DTC Chart
B0002 or
B0009Go 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
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—

6E–322 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS
DIAGNOSTIC TROUBLE CODE (DTC) P1611 (SYMPTOM CODE A)
(FLASH CODE 56) WRONG SECURITY CODE ENTERED
Condition for setting the DTC and action taken when the DTC sets
Circuit Description
The ECM decides whether that is an abnormality in the
immobilizer control system. DTC P1611 (Symptom
Code A) is recorded when received immobilizer security
code was not correct.
Diagnostic Aids
Check for the following conditions:
Poor connection at ECM and immobilizer control unit-
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 for
damage. If the harness appears to be OK, observe
the DTC P1611 display on the Tech2 while moving
connectors and wiring harnesses.
Flash
CodeCode Symptom
CodeMIL DTC Name DTC Setting Condition Fail-Safe (Back Up)
56 P1611 A - Wrong Security Code Entered Received security code is not
corre ct.1. Engine does not start.
2. Check e ngine lamp fla sh.

4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E–323
Diagnostic Trouble Code (DTC) P1611 (Sy mptom Code A) (Flash Code 56)
Wrong Security Code Entered
Step Action Value(s) Yes No
1Was the “On-Board Diagnostic (OBD) System Check”
performed?
—Go to Step 2Go 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 As Stored By ECU” in
“F0: Diagnostic Trouble Codes”.
Is the DTC P1611 (Symptom Code A) stored as
“Present Failure”?—Go to Step 3Refer to
Diagnostic Aids
and Go to Step
3
3 1. Using the Tech 2, ignition “On” and engine “Off”.
2. Select “F1: Clear DTC Information” in “F0:
Diagnostic Trouble Codes” with the Tech 2 and
clear the DTC information.
3. Operate the vehicle and monitor the “F0: Read
DTC Infor As Stored By ECU” in the “F0:
Diagnostic Trouble Codes”.
Was the DTC P1611 (Symptom Code A) stored in this
ignition cycle?—Go to Step 4Refer to
Diagnostic Aids
and Go to Step
4
4 1. Using the Tech 2, ignition “On” and engine “Off”.
2. Select “Immobilizer” in the system selection menu
“Body”.
3. Select “Read DTC Info Ordered By Priority” in the
“Diagnostic Trouble Code”.
Was the any DTC's B**** stored in this ignition cycle?—Refer to
“Immobilizer
Workshop
Manual” & Go
to DTC Chart
B**** 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
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—

6E–324 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS
DIAGNOSTIC TROUBLE CODE (DTC) P1612 (SYMPTOM CODE A)
(FLASH CODE 56) IMMOBILIZER NO OR WRONG SIGNAL
Condition for setting the DTC and action taken when the DTC sets
Circuit Description
The ECM decides whether that is an abnormality in the
immobilizer control system. DTC P1612 (Symptom
Code A) is recorded when received immobilizer
challenge signal was not correct.
Diagnostic Aids
Check for the following conditions:
Poor connection at ECM and immobilizer control unit-
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 for
damage. If the harness appears to be OK, observe
the DTC P1612 display on the Tech2 while moving
connectors and wiring harnesses.
Flash
CodeCode Symptom
CodeMIL DTC Name DTC Setting Condition Fail-Safe (Back Up)
56 P1612 A - Immobilizer No or Wrong Sig-
na lReceived challenge signal is
no t co rrect or not re ce iv ed.1. Engine does not start.
2. Check e ngine lamp fla sh.

4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E–325
Diagnostic Trouble Code (DTC) P1612 (Symptom Code A) (Flash Code 56)
Immobilizer No or Wrong Signal
Step Action Value(s) Yes No
1Was the “On-Board Diagnostic (OBD) System Check”
performed?
—Go to Step 2Go 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 As Stored By ECU” in
“F0: Diagnostic Trouble Codes”.
Is the DTC P1612 (Symptom Code A) stored as
“Present Failure”?—Go to Step 3Refer to
Diagnostic Aids
and Go to Step
3
3 1. Using the Tech 2, ignition “On” and engine “Off”.
2. Select “F1: Clear DTC Information” in “F0:
Diagnostic Trouble Codes” with the Tech 2 and
clear the DTC information.
3. Operate the vehicle and monitor the “F0: Read
DTC Infor As Stored By ECU” in the “F0:
Diagnostic Trouble Codes”.
Was the DTC P1612 (Symptom Code A) stored in this
ignition cycle?—Go to Step 4Refer to
Diagnostic Aids
and Go to Step
4
4 1. Using the Tech 2, ignition “On” and engine “Off”.
2. Select “Immobilizer” in the system selection menu
“Body”.
3. Select “Read DTC Info Ordered By Priority” in the
“Diagnositic Trouble Code”.
Was the DTC B0007 stored in this ignition cycle?—Refer to
“Immobilizer
Workshop
Manual” & Go
to DTC Chart
B0007 Go to Step 5
5 Check for poor/faulty connection at the immobilizer
control unit connector or ECM connector. If a poor/
faulty connection is found, repair as necessary.
Was the problem found?
—Verify repair Go to Step 6
42
35
78 C-56
B-68