fuel ISUZU TF SERIES 2004 Workshop Manual

3.5L ENGINE DRIVEABILITY AND EMISSIONS 6E-243
DIAGNOSTIC TROUBLE CODE (DTC) P0341(FLASH CODE 41) CAMSHAFT
POSITION SENSOR CIRCUIT RANGE/PERFORMANCE
DIAGNOSTIC TROUBLE CODE (DTC) P0342 (FLASH CODE 41) CAMSHAFT
POSITION SENSOR CIRCUIT NO SIGNAL



RUW46EMF000101

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)
P0341 B Camshaft Position
Sensor Circuit
Range/Performance 1. Engine speed below 2000rpm.
2. No crankshaft position sensor DTC P0336 or P0337.
3. Incorrect pulse is detected consecutively. 41

P0342 B Camshaft Position
Sensor Circuit No
Signal 1. No DTC relating to CKP sensor.
2. Engine speed is below 2000rpm.
3. No pulse is detected consecutively. Fuel cut is operated at high engine
speed.

6E-250 3.5L ENGINE DRIVEABILITY AND EMISSIONS

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)
P0351 A Ignition 1 Control
Circuit
P0352 A Ignition 2 Control
Circuit
P0353 A Ignition 3 Control
Circuit
P0354 A Ignition 4 Control
Circuit
P0355 A Ignition 5 Control
Circuit
42
P0356 A Ignition 6 Control
Circuit 1. No DTC relating to CMP sensor and CKP sensor.
2. Engine speed is between 250rpm and 850 rpm.
3. 10 ignition signals are not detected consecutively. Fuel cut is operated more than
2000rpm.

CIRCUIT DESCRIPTION
The Engine Control Module's (ECM) control circuit 1
provides a zero-volt or a 5-volt output signal to the
ignition coil. The normal voltage on the circuit is zero
volts. When the ignition coil receives the 5-volt signal
from the ECM, it provides a ground path for the B+
supply to the primary side of the number 1 ignition coil.
When the ECM shuts off the 5 volts to the ignition coil,
the ignition coil turns “OFF." This causes the ignition coil
primary magnetic field to collapse, producing a voltage
in the secondary coil which fires the spark plug.
The circuit between the ECM and ignition coil is
monitored for an open circuit, short to voltage, and shor
t
to ground. When the ECM detects a problem on ignition
control circuit, it will set a DTC P0351, P0352, P0353,
P0354, P0355 or P0356.

DIAGNOSTIC AIDS
Check for the following conditions:
 Poor connection at ECM – Inspect the harness
connectors for backed-out terminals, imprope
r
mating, broken locks, improperly formed or damaged
terminals, and poor terminal-to-wire connections.
 Damaged harness –Inspect the wiring harness fo
r
damage. If the harness appears to be OK, observe
the Tech 2 display related to DTC P0351 or P0352,
P0353, P0354, P0355 or P0356 while moving the
connector and wiring related to the ignition system.
A
change in the display will indicate the location of the
fault.
Reviewing the Failure Records vehicle mileage since
the diagnostic test last failed may help determine ho
w
often the condition that caused the DTC to be set
occurs. This may assist in diagnosing the condition.

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.

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

6E-332 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Step Action Value (s) Yes No
8
1. Using a Tech 2, display the IAC value.
2. Check for a faulty, plugged, or sticking IAC
operation.
Was the problem found?
- Verify repair Go to Step 9
9
Check the CKP sensor signal or installation condition.
Refer to DTC P0336 "Crankshaft Position Sensor
Circuit Range/Performance" and DTC P0337
"Crankshaft Position Sensor Circuit No Signal".
Was a problem found?
- Verify repair Go to Step 10
10
Check for proper ignition voltage output with the spark
tester.
Was a problem found?
- Verify repair Go to Step 11
11
1. Remove the spark plugs and check for gas or oil
fouling cracks, wear, improper gap, burned
electrodes, heavy deposits, or improper heat
range.
2. If spark plugs are fouled, the cause of fouling must
be determined before replacing the spark plugs.
Was a problem found?
- Verify repair Go to Step 12
12
Check the fuel pressure. Refer to Fuel System
Diagnosis.
Was a problem found?
- Verify repair Go to Step 13
13
Perform the procedure in Fuel System Pressure Test
to determine if there is a problem with fuel delivery.
Was a problem found?
- Verify repair Go to Step 14
14
Visually/physically check the vacuum hose for splits,
kinks and proper connections and routing.
Was a problem found?
- Verify repair Go to Step 15
15
Check the exhaust system for a possible restriction:

Damaged or collapsed pipes.

Internal muffler failure.
Was a problem found?
- Verify repair Go to Step 16
16
Check for the following engine mechanical problems
(refer to Engine Mechanical section):

Low compression.

Leaking cylinder head gaskets.

Worn camshaft.

Camshaft drive belt slipped or stripped.
Was a problem found?
- Verify repair Go to Step 17

3.5L ENGINE DRIVEABILITY AND EMISSIONS 6E-335
Step Action Value (s) Yes No
10
1. Remove the spark plugs and check for gas or oil
fouling cracks, wear, improper gap, burned
electrodes, heavy deposits, or improper heat
range.
2. If spark plugs are fouled, the cause of fouling must
be determined before replacing the spark plugs.
Was a problem found?
- Verify repair Go to Step 11
11
Check for water or alcohol contaminated fuel.
Was a problem found?
- Verify repair Go to Step 12
12
Perform the procedure in Fuel System Pressure Test
to determine if there is a problem with fuel delivery.
Refer to 6E-116 page.
Was a problem found?
- Verify repair Go to Step 13
13
1. Check the injector connectors.
2. If any of the connectors are connected at an
improper cylinder, connect as necessary.
Was a problem found?
- Verify repair Go to Step 14
14
Check for the following engine mechanical problems
(refer to Engine Mechanical section):

Low compression.

Leaking cylinder head gaskets.

Worn camshaft.

Camshaft drive belt slipped or stripped.
Was a problem found?
- Verify repair Go to Step 15
15
1. Review all diagnostic procedures within this table.
2. If all procedures have been completed and no
malfunctions have been found, review/inspect the
following:

Visual/physical inspection.

Tech 2 data.

All electrical connections within a suspected circuit
and/or system.
Was a problem found?
- Verify repair Go to Step 16
16
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 17

3.5L ENGINE DRIVEABILITY AND EMISSIONS 6E-339
Step Action Value (s) Yes No
12
Check the fuel control Heated Oxygen Sensor
(HO2S). When monitored on the Tech 2, the HO2S
should respond quickly to different throttle positions. If
it doesn't check for silicon or other contaminates from
fuel or use of improper sealant. The sensors may have
a white powdery coating. Silicon contamination sends
a rich exhaust signal which causes the ECM to
command and excessively lean air/fuel mixture.
Was a problem found?
- Verify repair Go to Step 13
13
Check the fuel pressure. Refer to Fuel System
Diagnosis.
Was a problem found?
- Verify repair Go to Step 14
14
Perform the procedure in Fuel System Pressure Test
to determine if there is a problem with fuel delivery.
Refer to 6E-116 page.
Was a problem found?
- Verify repair Go to Step 15
15
Monitor "B1S1 (Bank 1 Sensor 1) Status" and "B2S1
(Bank 2 Sensor 1) Status" on the Tech 2.
Is the "B1S1 (Bank 1 Sensor 1) Status" or "B2S1
(Bank 2 Sensor 1) Status" in the rich condition?
- Go to Step 16 Go to Step 17
16
Check items that can cause the engine to run rich.
Refer to DTC P0172 "O2 Sensor System Too Rich
(Bank 1)" or DTC P0175 "O2 Sensor System Too Rich
(Bank 2)".
Was a problem found?
- Verify repair Go to Step 18
17
Check items that can cause the engine to run lean.
Refer to DTC P0171 "O2 Sensor System Too Lean
(Bank 1)" or DTC P0174 "O2 Sensor System Tool
Lean (Bank 2)".
Was a problem found?
- Verify repair Go to Step 18
18
Check for proper ignition voltage output with the spark
tester.
Was a problem found?
- Verify repair Go to Step 19
19
Check the ignition coils for cracks or carbon tracking.
If a problem is found, repair as necessary.
Was a problem found?
- Verify repair Go to Step 20
20
1. Remove the spark plugs and check for gas or oil
fouling cracks, wear, improper gap, burned
electrodes, heavy deposits, or improper heat range.
2. If spark plugs are fouled, the cause of fouling must
be determined before replacing the spark plugs.
Was a problem found?
- Verify repair Go to Step 21
21
1. Check the injector connectors.
2. If any of the connectors are connected at an
improper cylinder, connect as necessary.
Was a problem found?
- Verify repair Go to Step 22

6E-342 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Step Action Value (s) Yes No
6
Remove the MAF & IAT sensor assembly and check
for the following conditions.

Objects blocking the air cleaner.

Objects blocking the MAF sensor.

Objects blocking the throttle valve.

Vacuum leaking at intake duct.

Vacuum leaking at throttle body.
If a problem is found, repair as necessary.
Was the problem found?
- Verify repair Refer to DTC
P0101 and Go to
Step 7
7
1. Using the Tech 2, ignition "On" and engine "Off".
2. Monitor the "Throttle Position" in the data display.
Does the Tech 2 indicate correct "Throttle Position"
from 0% to 100% depending on accelerator pedal
operation?




- Go to Step 9 Go to Step 8
8
1. Using the Tech 2, ignition "On" and engine "Off".
2. Monitor the "Throttle Position" in the data display.
3. Adjust the accelerator cable or TPS within 0% to
100%.
Is the action complete?
- Verify repair -
9
Check for the following conditions.

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 10
10
Check the fuel control Heated Oxygen Sensor
(HO2S). When monitored on the Tech 2, the HO2S
should respond quickly to different throttle positions. If
it doesn't check for silicon or other contaminates from
fuel or use of improper sealant. The sensors may have
a white powdery coating. Silicon contamination sends
a rich exhaust signal which causes the ECM to
command and excessively lean air/fuel mixture.
Was a problem found?
- Verify repair Go to Step 11
11
Check the fuel pressure. Refer to 6E-116 Fuel System
Diagnosis.
Was a problem found?
- Verify repair Go to Step 12
12
Monitor "B1S1 (Bank 1 Sensor 1) Status" and "B2S1
(Bank 2 Sensor 1) Status" on the Tech 2.
Is the "B1S1 (Bank 1 Sensor 1) Status" or "B2S1
(Bank 2 Sensor 1) Status" in the rich condition?
- Go to Step 13 Go to Step 14

3.5L ENGINE DRIVEABILITY AND EMISSIONS 6E-345
HESITATION, SAG, STUMBLE SYMPTOM
DEFINITIONS: Momentary lack of response as the
accelerator is pushed down. Can occur at any vehicle
speed. Usually most pronounced when first trying to
make the vehicle move, as from a stop sign. May cause
the engine to stall if severe enough.




time rpm
Sug
Hesitation Stumble



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 fuel quality.
Is the customer using improper fuel or degraded fuel?
- Replace fuel Go to Step 5
5
1. Using the Tech 2, ignition "On" and engine "On".
2. Monitor the "Mass Air Flow" in the data display.
Does the Tech 2 indicate correct "Mass Air Flow" as
shown in the following graph, when engine speed is
increasing little by little?

Characteris tic of MAF Sens or -Ref erence (No Engine Load)-
0 5 10 15 20 25 30 35 40 45 50
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
Eng i ne Speed ( r pm) ( T ech2 R eadi ng )
Mass Air Flow (g/s)
( T ec h2 R eadi ng)
- Go to Step 7 Go to Step 6