ignition ISUZU TF SERIES 2004 Workshop Manual

6E–220 ENGINE DRIVEABILITY AND EMISSIONS
7 Using the DVM and check the “CHECK ENGINE”
lamp circuit.
Breaker box is available:
1. Ignition “Off”, engine “Off”.
2. Install the breaker box as type A. (ECM
disconnected) Refer to 6E-88 page.
3. Disconnect the immobilizer control unit connector.
4. Check the circuit for open or short to ground
circuit.
Was the problem found?
Breaker box is not available:
1. Ignition “Off”, engine “Off”.
2. Disconnect the the immobilizer control unit
connector and 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 8
8 Using the DVM and check the VSS signal circuit.
1. Ignition “Off”, engine “Off”.
2. Disconnect the immobilizer control unit connector
and ECM connector.
3. Ignition “On”.
4. Check the circuit for short to power supply circuit.
Was the problem found?
—Repair faulty
harness and
verify repair Go to Step 9 Step A ction Value(s) Yes No
J2-32
Brea ker Bo xB-24





C-56(J2) 327B-68
VV
C-56(J2)
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B-68

ENGINE DRIVEABILITY AND EMISSIONS 6E–221
9 Using the DVM and check the VSS signal circuit.
Breaker box is available:
1. Ignition “Off”, engine “Off”.
2. Install the breaker box as type A. (ECM
disconnected) Refer to 6E-88 page.
3. Disconnect the immobilizer control unit connector.
4 . C h e c k t h e c i r c u i t f o r o p e n o r s h o t t o g r o u n d c i r c u i t .
Was the problem found?
Breaker box is not available:
1. Ignition “Off”, engine “Off”.
2. Disconnect the immobilizer control unit connector
and 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 Srtep 10
10 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 11
11 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.—Veri fy repai r— Step A ction Value(s) Yes No
J2-23Breaker BoxB-68




23B-68
C-56(J2)
8

6E–222 ENGINE DRIVEABILITY AND EMISSIONS
DIAGNOSTIC TROUBLE CODE (DTC) P1631
IMMOBILIZER WRONG SIGNAL
Condition for setting the DTC and action taken when the DTC sets
Circuit Description
The ECM decides whether that is an abnomality in the
immobilizer control system. DTC P1631 is recorded by
the ECM when received response was not correct.
Diagnostic Aids
Check for the following conditions:
Poor connection at ECM and Immobilizer-Inspect
harness connectors for backed out terminals,
improper mating, broken locks, improperly formed ordamaged terminals, and poor terminal to wire
connection.
Damaged harness-Inspect the wiring harness for
damage, If the harness appears to be OK, disconnect
the ECM and Immobilizer, turn the ignition “ON” and
observe a voltmeter connected to the suspect driver
circuit at the ECM and Immobilizer harnass connector
while moving connectors and wiring harnesses
relates to the MIL. A change in voltage will indicate
the location of the fault.
Code Type DTC Name DTC Setting Condition Fail-Safe (Back Up)
P1631 - Immobilizer Wrong Signal Received response is not correct. 1. Engine does not start.
2. Check engine lamp flash.

ENGINE DRIVEABILITY AND EMISSIONS 6E–223
Diagnostic Trouble Code (DTC) P1631 Immobilizer Wrong Signal
Step A ction Value(s) Yes No
1 Was 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 By Priority” in “F0:
Diagnostic Trouble Code”.
Is the DTC P1631 stored as “Present Failure”?—Go to Step 3Refer to
Diagnostic Aids
and Go to Step
3
3 1. Using the Tech2, ignition “On” and engine “Off”.
2. Select “Clear DTC Information” with the Tech2 and
clear the DTC information.
3. Operate the vehicle and monitor the “F5: Failed
This Ignition” in “F2: DTC Information”.
Was the DTC P1631 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 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.—Veri fy repai r—

6E–224 ENGINE DRIVEABILITY AND EMISSIONS
DIAGNOSTIC TROUBLE CODE (DTC) P1648
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 abnomality in the
immobilizer control system. DTC P1648 is recorded by
the ECM when received incorrect security code.
Diagnostic Aids
Check for the following conditions:
Poor connection at ECM and Immobilizer-Inspect
harness connectors for backed out terminals,
improper mating, broken locks, improperly formed ordamaged terminals, and poor terminal to wire
connection.
Damaged harness Inspect the wiring harness for
damage, If the harness appears to be OK, disconnect
the ECM and Immobilizer, turn the ignition “ON” and
observe a voltmeter connected to the suspect driver
circuit at the ECM and Immobilizer harnass connector
while moving connectors and wiring harnesses
relates to the MIL. A change in voltage will indicate
the location of the fault.
Code Type DTC Name DTC Setting Condition Fail-Safe (Back Up)
P1648 - Wrong Security Code Entered Received incorrect security code. 1. Engine does not start.
2. Check engine lamp flash.

ENGINE DRIVEABILITY AND EMISSIONS 6E–225
Diagnostic Trouble Code (DTC) P1648 Wrong Security Code Entered
Step A ction Value(s) Yes No
1 Was 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 By Priority” in “F0:
Diagnostic Trouble Code”.
Is the DTC P1648 stored as “Present Failure”?—Go to Step 3Refer to
Diagnostic Aids
and Go to Step
3
3 1. Using the Tech2, ignition “On” and engine “Off”.
2. Select “Clear DTC Information” with the Tech2 and
clear the DTC information.
3. Operate the vehicle and monitor the “F5: Failed
This Ignition” in “F2: DTC Information”.
Was the DTC P1648 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 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.—Veri fy repai r—

6E–226 ENGINE DRIVEABILITY AND EMISSIONS
DIAGNOSTIC TROUBLE CODE (DTC) P1649
IMMOBILIZER FUNCTION NOT PROGRAMMED
Condition for setting the DTC and action taken when the DTC sets
Circuit Description
The ECM decides whether that is an abnomality in the
immobilizer control system. DTC P1649 is recorded by
the ECM when security code & secret key not
programmed.
Diagnostic Aids
Check for the following conditions:
Poor connection at ECM and Immobilizer-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, disconnect
the ECM and Immobilizer, turn the ignition “ON” and
observe a voltmeter connected to the suspect driver
circuit at the ECM and Immobilizer harnass connector
while moving connectors and wiring harnesses
relates to the MIL. A change in voltage will indicate
the location of the fault.
Code Type DTC Name DTC Setting Condition Fail-Safe (Back Up)
P1649 - Immobilizer Function Not Programmed Immobilizer function is not programmed in the
ECM.1. Engine doe s no t start.
2. Check engine lamp flash.

ENGINE DRIVEABILITY AND EMISSIONS 6E–227
Diagnostic Trouble Code (DTC) P1649 Immobilizer Function Not Programmed
Step A ction Value(s) Yes No
1 Was 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 By Priority” in “F0:
Diagnostic Trouble Code”.
Is the DTC P1649 stored as “Present Failure”?—Go to Step 3Refer to
Diagnostic Aids
and Go to Step
3
3 1. Using the Tech2, ignition “On” and engine “Off”.
2. Select “Clear DTC Information” with the Tech2 and
clear the DTC information.
3. Operate the vehicle and monitor the “F5: Failed
This Ignition” in “F2: DTC Information”.
Was the DTC P1649 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”.
Were 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.—Veri fy repai r—

ENGINE DRIVEABILITY AND EMISSIONS 6E–229
Diagnostic Trouble Code (DTC) P1693 Tachometer Output Low Voltage
Step A ction Value(s) Yes No
1 Was 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 By Priority” in “F0:
Diagnostic Trouble Code”.
Is the DTC P1693 stored as “Present Failure”?—Go to Step 3Refer to
Diagnostic Aids
and Go to Step
3
3 1. Using the Tech2, ignition “On” and engine “Off”.
2. Select “Clear DTC Information” with the Tech2 and
clear the DTC information.
3. Operate the vehicle and monitor the “F5: Failed
This Ignition” in “F2: DTC Information”.
Was the DTC P1693 stored in this ignition cycle?—Go to Step 4Refer to
Diagnostic Aids
and Go to Step
4
4 Check for poor/faulty connection at the ECM or meter
connector. If a poor/faulty connection is found, repair
the faulty terminal.
Was the problem found?
—Verify repair Go to Step 5
5 If a oscilloscope is available, monitor the Tachometer
output signal. Does the oscilloscope indicate correct
wave form?
—Go to Step 10Not available:
Go to Step 6
Fix ed at low:
Go to Step 6
Fixed at High:
Go to Step 7
25
C-56(J2) B-24
11
Crankshaft Position (CKP) Sensor & Tacho Output Signa l
Reference Wave Form





CH1
0V





CH2
0V




Measurem ent Terminal: CH1: J1-21(+) / CH2: J2-25(+) GND(-)
Measurem ent Scale: CH1: 2V/d iv / CH2: 10V/div 5ms/div
Measurement Condition: Approx imately 2000rpm

6E–230 ENGINE DRIVEABILITY AND EMISSIONS
6 Using the DVM and check the Tacho output circuit.
Breaker box is available:
1. Ignition “Off”, engine “Off”.
2. Install the breaker box as type A. (ECM
disconnected) Refer to 6E-88 page.
3. Disconnect the meter connector.
4. Check the circuit for open or short to ground
circuit.
Was the problem found?
Breaker box is not available:
1. Ignition “Off”, engine “Off”.
2. Disconnect the ECM connector.
3. Disconnect the meter connector.
4. Check the circuit for open or short to ground
circuit.
Was the problem found?
—Repair faulty
harness and
verify repair Go to Step 7
7 Using the DVM and check the Tacho output circuit.
1. Ignition “On”, engine “Off”.
2. Disconnect the meter connector.
3. Check the circuit for short to power supply circuit.
Was the DVM indicated specified value?
Less than 1V Go to Step 8Repair faulty
harness and
verify repair
8 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 Step A ction Value(s) Yes No
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11