2004 ISUZU TF SERIES lock

3.5L ENGINE DRIVEABILITY AND EMISSIONS 6E-279
DIAGNOSTIC TROUBLE CODE (DTC) P0500 (FLASH CODE 24) VEHICLE
SPEED SENSOR (VSS) CIRCUIT RANGE/PERFORMANCE



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)
24 P0500 B Vehicle Speed Sensor
Circuit
Range/Performance 1. Engine speed is below 5000rpm.
2. Under fuel cut operation.
3. Vehicle speed sensor output is below 1km/h.
Above conditions are met for 4 seconds. The ECM use 10km/h condition as
substitute.


CIRCUIT DESCRIPTION
The vehicle speed sensor has a magnet rotated by the
transmission output shaft. Attached to the sensor is a
hall effect circuit the interacts with the magnetic field
treated by the rotating magnet. A 12-volt operating
supply for the speed sensor hall circuit is supplied from
the meter fuse. The VSS pulses to ground the 9-vol
t
signal sent from the Engine Control Module (ECM) on
the reference circuit. The ECM interprets vehicle speed
by the number of pulses to ground per second on the
reference circuit.

DIAGNOSTIC AIDS
An intermittent may be caused by a poor connection,
rubbed–through wire insulation or a wire broken inside
the insulation. Check for:
 Poor connection —Inspect the ECM harness and
connectors for improper mating, broken locks,
improperly formed or damaged terminals, and poo
r
terminal-to-wire connection.
 Damaged harness —Inspect the wiring harness fo
r
damage.

3.5L ENGINE DRIVEABILITY AND EMISSIONS 6E-297
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)
P1508 B Idle Air Control System
Low/Closed 1. No DTC relating to MAF sensor, IAT sensor, ECT sensor,
TPS, CMP sensor, CKP sensor, VSS and system voltage.
2. Engine speed is between 675rpm and 6000rpm.
3. Engine coolant temperature is more than 75
C.
4. Intake air temperature is between -10
C and 80
C.
5. Vehicle is stopping.
6. Small amount of intake air through the idle air control
valve. (Idle air control valve is sticking at close position.)
Above conditions are met for 2 seconds. 22
P1509 B Idle Air Control System
High/Open 1. No DTC relating to MAF sensor, IAT sensor, ECT sensor,
TPS, CMP sensor, CKP sensor, VSS and system voltage.
2. Engine speed is between 675rpm and 6000rpm.
3. Engine coolant temperature more than 75
C.
4. Intake air temperature is between -10
C and 80
C.
5. Vehicle is stopping.
6. Large amount of intake air through the idle air control
valve. (Idle air control valve is sticking at open position.)
Above conditions are met for 2 seconds. Fuel cut is operated at high idle
speed.

CIRCUIT DESCRIPTION
The engine control module (ECM) controls engine idle
speed by adjusting the position of the idle air control
(IAC) motor pintle. The IAC is a bi-directional steppe
r
motor driven by two coils. The ECM applies current to
the IAC coils in steps (counts) to extend the IAC pintle
into a passage in the throttle body to decrease air flow.
The ECM reverses the current to retract the pintle,
increasing air flow. This method allows highly accurate
control of idle speed and quick response to changes in
engine load. If the ECM detects a condition where too
low of an idle speed is present and the ECM is unable
to adjust idle speed by increasing the IAC counts, DTC
P1508 or P1509 will set, indicating a problem with the
idle control system.

DIAGNOSTIC AIDS
Check for the following conditions:
 Poor connection at ECM or IAC motor –Inspec
t
harness connectors for backed-out terminals,
improper mating, broken locks, improperly formed o
r
damaged terminals, and poor terminal-to-wire
connection.
 Damaged harness – Inspect the wiring for damage.
 Restricted air intake system – Check for a possible
collapsed air intake duct, restricted air filter element,
or foreign objects blocking the air intake system.

6E-298 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P1508 (Flash Code 22) Idle Air
Control System Low/Closed
Diagnostic Trouble Code (DTC) P1509 (Flash Code 22) Idle Air
Control System High/Open
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 P1508 or P1509 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 P1508 or P1509 stored in this ignition
cycle?
- Go to Step 4 Refer to
Diagnostic Aids
and Go to Step 4
4
Check for the following conditions.

Objects blocking the Idle Air Control (IAC) Valve.

Objects blocking the throttle valve.

Vacuum leaking at throttle body.
If a problem is found, repair as necessary.
Was the problem found?
- Verify repair Go to Step 5
5
Check for poor/faulty connection at the IAC Valve or
ECM connector.
If a poor/faulty connection is found, repair the faulty
terminal.
Was the problem found?
E-61(B)







E-70






- Verify repair Go to Step 6

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.

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.

3.5L ENGINE DRIVEABILITY AND EMISSIONS 6E-325
DIAGNOSTIC TROUBLE CODE (DTC) P1648 WRONG SECURITY CODE
ENTERED



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 P1648 - Wrong Security Code
Entered Received incorrect security code. 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 P1648 is recorded by
the ECM when received security code 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.

3.5L ENGINE DRIVEABILITY AND EMISSIONS 6E-327
DIAGNOSTIC TROUBLE CODE (DTC) P1649 IMMOBILIZER FUNCTION
NOT PROGRAMMED



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 P1649 - Immobilizer Function
Not Programmed Immobilizer function is not programmed in the ECM. 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 P1649 is recorded by
the ECM when immobilizer function was no
t
programmed in the ECM.

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.

3.5L ENGINE DRIVEABILITY AND EMISSIONS 6E-331
ENGINE CRANKS BUT WILL NOT RUN
DEFINITIONS: Engine cranks, but will not run. (The
engine never start.)
NOTE: 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.
Should Tech2 display "SPS Procedure was not
successful", engine will not start, but no DTCs are
present, low battery voltage or poor electrical
connections should be the primary
suspects.Perform the SPS procedure again after
rectifying the fault/s.
NOTE: The vehicle with immobilizer system, this
system may be activated. Check the immobilizer
system diagnosis.


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. Perform a bulletin search.
2. If a bulletin that addresses the symptom is found,
correct the condition as instructed in the bulletin.
Was a bulletin found that addresses the symptom?
- Verify repair Go to Step 3
3
Was a visually/physical check performed?
- Go to Step 4 Go to Visual /
physical Check
4
Check the "Meter" fuse (15A), "Engine" fuse (15A),
"IGN Coil" fuse (15A) and "Fuel Pump" fuse (20A). If
the fuse is burnt out, repair as necessary.
Was the problem found?
- Verify repair Go to Step 5
5
Check the ECM grounds to verify that they are clean
and tight. Refer to the ECM wiring diagrams.
Was a problem found?
- Verify repair Go to Step 6
6
Check the fuel quality.
Is the customer using proper fuel?
- Go to Step 7
Replace fuel
7
Visually/physically inspect for the following conditions:

Restrict air intake system. Check for a restricted air
filter element, or foreign objects blocking the air
intake system.

Check for objects blocking the IAC passage or
throttle bore, excessive deposits in the throttle bore
and on the throttle plate.

Check for a condition that causes a large vacuum
leak, such as an incorrectly installed or faulty
crankcase ventilation hose/brake booster hose.
Was a problem found?
- Verify repair Go to Step 8