2004 ISUZU TF SERIES check engine

6E-352 3.5L ENGINE DRIVEABILITY AND EMISSIONS
LACK OF POWER, SLUGGISH OR SPONGY SYMPTOM
DEFINITIONS: Engine delivers less than expected
power. Attempting part-throttle acceleration results in
little or no increase in vehicle speed.



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
1. Remove and check the air filter element for dirt or
restrictions.
2. Replace the air filter element if necessary.
Was a repair required?
- Verify repair Go to Step 5
5
Check the fuel quality.
Is the customer using improper fuel or degraded fuel?
- Replace fuel Go to Step 6
6
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 8 Go to Step 7

3.5L ENGINE DRIVEABILITY AND EMISSIONS 6E-353
Step Action Value (s) Yes No
7
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 8
8
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 10Go to Step 9
9
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 -
10
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 11
11
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 12
12
Check the fuel pressure. Refer to 6E-116 Fuel System
Diagnosis.
Was a problem found?
- Verify repair Go to Step 13
13
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 14Go to Step 15
14
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 16

6E-354 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Step Action Value (s) Yes No
15
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 16
16
Check for proper ignition voltage output with the spark tester.
Was a problem found?
- Verify repair Go to Step 17
17
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 18
18
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 19
19
Visually/physically check the vacuum hose for splits, kinks and
proper connections and routing.
Was a problem found?
- Verify repair Go to Step 20
20
Check the exhaust system for a possible restriction:

Damaged or collapsed pipes.

Internal muffler failure.
Was a problem found?
- Verify repair Go to Step 21
21
Check the torque converter clutch (TCC) for proper operation
(if A/T model). If a problem is found, repair as necessary.
Was a problem found?
- Verify repair Go to Step 22
22
Check for the following engine mechanical problems (refer to
Engine Mechanical Section):

Low compression.

Leaking cylinder head gaskets.

Worn camshaft.

Sticking or leaking valves.

Valve timing.

Broken valve springs.

Camshaft drive belt slipped or stripped.
Was a problem found?
- Verify repair Go to Step 23
23
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 24

6E-356 3.5L ENGINE DRIVEABILITY AND EMISSIONS
DETONATION/SPARK KNOCK SYMPTOM
DEFINITIONS: A mild to sever ping, usually worse
under acceleration. The engine makes a shape metallic
knocking sound that changes with throttle opening.
Prolonged detonation may lead to complete engine
failure.



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
1. If Tech 2 readings are normal (refer to Typical Scan
Data Values) and there are no engine mechanical
faults, fill the fuel tank with a known quality
gasoline.
2. Re-evaluate the vehicle performance.
Is detonation present?
- Go to Step 5
Verify repair
5
Check for obvious overheating problems:

Low engine coolant.

Restricted air flow to radiator.

Incorrect coolant solution.
If a problem is found, repair as necessary.
Was a problem found?
- Verify repair Go to Step 6
6
1. Using a Tech 2, display the ECT sensor and IAT
sensor value.
2. Check the specified value or wire.
Was the problem found?
- Verify repair Go to Step 7

3.5L ENGINE DRIVEABILITY AND EMISSIONS 6E-357
Step Action Value (s) Yes No
7
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 9 Go to Step 8
8
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 9
9
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 11 Go to Step 10
10
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 -
11
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 12

6E-358 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Step Action Value (s) Yes No
12
Check the fuel pressure. Refer to Fuel System
Diagnosis.
Was a problem found?
- Verify repair Go to Step 13
13
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 lean condition?
- Go to Step 14 Go to Step 15
14
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 15
15
Check spark plugs for proper heat range.
Were incorrect spark plugs installed?
- Verify repair Go to Step 16
16
1. Remove excessive carbon buildup with a top
engine cleaner.
2. Re-evaluate vehicle performance.
Is detonation still present?
- Verify repair Go to Step 17
17
Check for an engine mechanical problem. Perform a
cylinder compression check. Refer to Engine
Mechanical.
Was a problem found?
- Verify repair Go to Step 18
18
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 19
19
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 20
20
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-359
POOR FUEL ECONOMY SYMPTOM
DEFINITIONS: Fuel economy, as measured by an
actual road test, is noticeably lower than expected. Also,
economy is noticeably lower than it was on this vehicle
at one time, as previousl shown by an actual road test.
(Larger than standard tires will cause odomete
r
readings to be incorrect, and that may cause fuel
economy to appear poor when it is actually normal.)



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 owner's driving habits.

Is the A/C On full time (defroster mode On)?

Are tires at the correct pressure?

Are excessively heavy loads being carried?

Is acceleration too much, too often?
- Go to Step 5 Go to Step 6
5
Review the items in Step 4 with the customer and
advise as necessary.
Is the action complete?
- System OK -
6
Visually/physically check: Vacuum hoses for splits,
kinks, and improper connections.
Was a problem found?
- Verify repair Go to Step 7
7
Check for low engine coolant level.
Was a problem found?
- Verify repair Go to Step 8
8
Check for incorrect or faulty engine thermostat. Refer
to Engine Cooling.
Was a problem found?
- Verify repair Go to Step 9
9
Remove and check the air filter element for dirt or for
restrictions.
Was a problem found?
- Verify repair Go to Step 10
10
Check the torque converter clutch (TCC) for proper
operation (if A/T model). If a problem is found, repair
as necessary.
Was a problem found?
- Verify repair Go to Step 11

6E-360 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Step Action Value (s) Yes No
11
1. Using a Tech 2, display the ECT sensor and IAT
sensor value.
2. Check the specified value or wire.
Was the problem found?
- Verify repair Go to Step 12
12
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 13
13
Check for proper calibration of the speedometer.
Does the speed indicated on the speed meter closely
match the vehicle speed displayed on the Tech 2?
- Go to Step 15 Go to Step 14
14
Diagnose and repair the inaccurate speedometer
condition as necessary. Refer to Vehicle Speed
Sensor in Electrical Diagnosis.
- Verify repair -
15
Check for proper calibration of the fuel gauge.
Was a problem found?
- Verify repair Go to Step 16
16
Check for the following engine mechanical problems
(refer to Engine Mechanical):

Low compression.

Worn camshaft.

Sticking or leaking valves.

Valve timing.
Was a problem found?
- Verify repair Go to Step 17
17
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 18
18
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 19