ECU ISUZU TF SERIES 2004 Workshop Manual

4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E–303
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 P1173 (Symptom Code 3) stored in this
ignition cycle?—Go to Step 4Refer to
Diagnostic Aids
and Go to Step
4
4 Check the engine overheat condition.
Was the problem found?
—Repair the
cause of
overheat and
verify repair Go to Step 5
5 1. Using the Tech 2, ignition “On” and engine “On”.
2. Monitor the “Coolant Temperature” in the data
display.
Does the Tech 2 indicate correct “Coolant
Temperature” depending on warm up time?—Go to Step 9Go to Step 6
6 Using the DVM and check the ECT sensor.
1. Ignition “Off”, engine “Off”.
2. Disconnect ECT sensor connector.
3. Measure the resistance of ECT sensor.
Does the tester indicate standard resistance as shown
in the following table?
Standard
resistance Go to Step 9Go to Step 7
7 Substitute a known good ECT sensor assembly and
recheck.
Was the problem solved?—Go to Step 8Go to Step 9
8 Replace the ECT sensor.
Is the action complete?—Verify repair—
9 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 10 Step Action Value(s) Yes No
Temperature (°C) Re sista nce (
) (Appro xima te ly )
-20 16100
0 5760
20 2370
40 1080
60 537
80 290
100 161
120 95
1 2
ECT Sensor
1 2

4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E–305
Diagnostic Trouble Code (DTC) P1173 (Symptom Code 7) (Flash Code 22) Fuel
Reduction Caused By High Fuel Temperature
Diagnostic Trouble Code (DTC) P1173 (Sy mptom Code A) (Flash Code 22) Fuel
Reduction Caused By Low Fuel Temperature
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 P1173 (Symptom Code 7) or P1173
(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 P1173 (Symptom Code 7) or P1173
(Symptom Code A) 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 Substitute a known good ECM and recheck.
Was the problem solved?
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. —Go to Step 6Go to Step 7
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—
7 Replace the injection pump assembly.
Is the action complete?—Verify repair—

4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E–307
Damaged harness-Inspect the wiring harness for
damage. If the harness appears to be OK, observe
the “Engine Speed” display on the Tech2 whilemoving connectors and wiring harness related to the
sensor.
Diagnostic Trouble Code (DTC) P1335 (Symptom Code A) (Flash Code 43)
Engine Speed Output Circuit Malfunction
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 P1335 (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 P1335 (Symptom Code A) stored in this
ignition cycle?—Go to Step 4Refer to
Diagnostic Aids
and Go to Step
4
4 Was the DTC P0335 (Symptom Code B) or P0335
(Symptom Code D) stored at the same time?
—Go to DTC
Chart P0335
(Symptom
Code B)
(Symptom
Code C)Go to Step 5
5 Check for poor/faulty connection at the ECM or PSG
(pump control unit) connector. If a poor/faulty
connection is found, repair the faulty terminal.
Was the problem found?
—Verify repair Go to Step 6
91
8C-57(B) E-6

6E–312 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P1345 (Symptom Code A) (Flash Code 45)
Camshaft Speed Malfunction
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 P1345 (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 P1345 (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. Monitor the “Pump Speed” in the data display.
Does the Tech 2 indicate correct “Pump Speed”
depending on engine speed?—Go to Step 6Go to Step 5
5 Check any accessory parts which may cause electric
interference or magnetic interference.
Was the problem found?—Remove the
accessory parts
and verify repair Go to Step 9
6 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 7
7 Substitute a known good ECM and recheck.
Was the problem solved?
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. —Go to Step 8Go to Step 9
8 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—
9 Replace the injection pump assembly.
Is the action complete?—Verify repair—

4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E–313
DIAGNOSTIC TROUBLE CODE (DTC) P1520 (SYMPTOM CODE A)
(FLASH CODE 47) NEUTRAL SWITCH ON ERROR
DIAGNOSTIC TROUBLE CODE (DTC) P1520 (SYMPTOM CODE B)
(FLASH CODE 47) NEUTRAL SWITCH OFF ERROR
Condition for setting the DTC and action taken when the DTC sets
Circuit Description
The ECM monitors the neutral switch (A/T: N or P
position switch in inhibitor switch) signal on the feed
terminal to the ECM. If the neutral switch with
malfunction, DTC P1520 (Symptom Code A) or P1520(Symptom Code B) will be stored.Diagnostic Aids
An intermittent may be caused by the following:
Poor connections.
Flash
CodeCode Symptom
CodeMIL DTC Name DTC Setting Condition Fail-Safe (Back Up)
47 P1520 A ON Neutra l Switch ON Error Neutra l switch signa l is input-
te d “On” thre e times co nsecu-
tively under driving
conditio ns.No fa il-sa fe fun ctio n.
B ON Neutra l Switch OFF Erro r Neutra l switch signa l is input-
te d “Off” three time s co nse cu-
tively under driving
conditio ns.

6E–314 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS
Misrouted harness.
Rubbed through wire insulation.
Broken wire inside the insulation.
Check for the following conditions:
Poor connection at ECM-Inspect harness connectors
for backed out terminals, improper mating, broken
locks, improperly formed or damaged terminals, andpoor terminal to wire connection.
Damaged harness-Inspect the wiring harness for
damage. If the harness appears to be OK, observe
the “Neutral Switch” display on the Tech2 while
moving connectors and wiring harness related to the
sensor.
Diagnostic Trouble Code (DTC) P1520 (Symptom Code A) (Flash Code 47)
Neutral Switch ON Error
Diagnostic Trouble Code (DTC) P1520 (Symptom Code B) (Flash Code 47)
Neutral Switch OFF Error
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 P1520 (Symptom Code A) or P1520
(Symptom Code B) 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 P1520 (Symptom Code A) or P1520
(Symptom Code B) stored in this ignition cycle?—Go to Step 4Refer to
Diagnostic Aids
and Go to Step
4

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—