ISUZU TF SERIES 2004 Workshop Manual

3.5L ENGINE DRIVEABILITY AND EMISSIONS 6E-315
Step Action Value (s) Yes No
12

Using the DVM and check the CAN BUS low circuit.
Breaker box is available:
1. Ignition "Off", engine "Off".
2. Install the breaker box as type A (ECM
disconnected).
Refer to 6E-95 page.
3. Disconnect the TCM connector.
4. Check the circuit for open or short to ground circuit.
Was the problem found?
A11
Breaker Box







Breaker box is not available:
1. Ignition "Off", engine "Off".
2. Disconnect the TCM connector and ECM
connector.
3. Check the circuit for open or short to ground circuit.
Was the problem found?
E-60(A)










-

Repair faulty
harness and
verify repair

Go to Step 13
13
Is the ECM or TCM programmed with the latest
software release?
If not, download the latest software to the ECM or
TCM using the "SPS (Service Programming
System)".
Was the problem solved?
- Verify repair Go to Step 14
14
Replace the TCM.
Was the problem solved?
IMPORTANT: The replacement TCM must be
programmed. "SPS (Service Programming System)
and is necessary."
- Verify repair Go to Step 15

6E-316 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Step Action Value (s) Yes No
15
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-317
DIAGNOSTIC TROUBLE CODE (DTC) P1626 IMMOBILIZER NO SIGNAL



RTW46EMF000301

Condition For Setting The DTC and Action Taken When The DTC Sets
Flash
Code Code Type DTC Name DTC Setting Condition Fail-Safe (Back Up)
67 P1626 - Immobilizer No Signal No response from immobilizer control unit. 1. Engine does not start.
2. Check engine lamp flash.

CIRCUIT DESCRIPTION
The Engine Control Module (ECM) decides whether that
is an abnomality in the immobilizer control system. DTC
P1626 is recorded by the ECM when no response from
immoblizer.

DIAGNOSTIC AIDS
Check for the following conditions:

Poor connection at Engine Control Module (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
harness connector while moving connectors and
wiring harnesses relates to the Check Engine Lamp
(MIL). A change in voltage will indicate the location
of the fault.

6E-318 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P1626 Immobilizer No Signal

Step Action Value (s) Yes No
1
Was the "On-Board Diagnostic (OBD) System Check"
performed?
- Go to Step 2 Go 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 P1626 stored as "Present Failure"?
- Go to Step 3 Refer 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 P1626 stored in this ignition cycle?
- Go to Step 4 Refer to
Diagnostic Aids
and Go to Step 4
4
Check any accessory parts which may cause electric
interference.
Was the problem found?
- Remove the
accessory parts
and verify repair Go to Step 5
5
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 6
6
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?
E-61(B)
B-68



- Verify repair Go to Step 7

3.5L ENGINE DRIVEABILITY AND EMISSIONS 6E-319
Step Action Value (s) Yes No
7
Using the DVM and check the "CHECK ENGINE"
lamp circuit.
1. Ignition "Off", engine "Off".
2. Disconnect the meter connector and immobilizer
control unit connector.
3. Ignition "On".
4. Check the circuit for short to power supply circuit.
Was the problem found?
B-68

V

-
Repair faulty
harness and
verify repair
Go to Step 8

6E-320 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Step Action Value (s) Yes No
8

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-95 page.
3. Disconnect the immobilizer control unit connector.
4. Check the circuit for open or short to ground circuit.
Was the problem found?
B18
Breaker Box


B-68






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?
E-61(B)
B-68








-

Repair faulty
harness and
verify repair

Go to Step 9

3.5L ENGINE DRIVEABILITY AND EMISSIONS 6E-321
Step Action Value (s) Yes No
9
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?
B-68

V

-
Repair faulty
harness and
verify repair
Go to Step 10
10

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-95 page.
3. Disconnect the immobilizer control unit connector .
4. Check the circuit for open or shot to ground circuit.
Was the problem found?
B32
Breaker Box


B-68






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?
B-68

E-61(B)








-

Repair faulty
harness and
verify repair

Go to Srtep 11

6E-322 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Step Action Value (s) Yes No
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 -

3.5L ENGINE DRIVEABILITY AND EMISSIONS 6E-323
DIAGNOSTIC TROUBLE CODE (DTC) P1631 IMMOBILIZER WRONG SIGNAL



RTW46EMF000301

Condition For Setting The DTC and Action Taken When The DTC Sets
Flash
Code Code Type DTC Name DTC Setting Condition Fail-Safe (Back Up)
67 P1631 - Immobilizer Wrong
Signal Received response is not correct. 1. Engine does not start.
2. Check engine lamp flash.

CIRCUIT DESCRIPTION
The ECM decides whether that is an abnormality 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 Engine Control Module (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
harness connector while moving connectors and
wiring harnesses relates to the Check Engine Lamp
(MIL). A change in voltage will indicate the location
of the fault.

6E-324 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P1631 Immobilizer Wrong Signal
Step Action Value (s) Yes No
1
Was the "On-Board Diagnostic (OBD) System Check"
performed?
- Go to Step 2 Go 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 3 Refer 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 4 Refer 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 any DTC's B0005 or B0006 stored in this
ignition cycle?
- Refer to
"Immobilizer
Workshop
Manual" & Go to
DTC Chart
B0005 or B0006 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 -