engine overheat ISUZU TF SERIES 2004 Owner's Manual

ENGINE DRIVEABILITY AND EMISSIONS 6E–65
Step 3: Simulate the symptom and isolate the
problem
Simulate the symptom and isolate the system by
reproducing all possible conditions suggested in Step 1
while monitoring suspected circuits/components/
systems to isolate the problem symptom. Begin with the
most logical circuit/component.
Isolate the circuit by dividing the suspect system into
simpler circuits. Nex t, confine the problem into a smaller
area of the system. Begin at the most logical point (or
point of easiest access) and thoroughly check the
isolated circuit for the fault, using basic circuit tests.
Hints
You can isolate a circuit by:
Unplugging connectors or removing a fuse to
separate one part of the circuit from another
If only component fails to operate, begin testing the
component
If a number of components do not operate, begin test
at areas of commonality (such as power sources,
ground circuits, switches, main connectors or major
components)
Substitute a known good part from the parts
department or the vehicle system
Try the suspect part in a known good vehicle
See Symptom Simulation Tests on the nex t page for
problem simulation procedures. Refer to service manual
sections 6E and 8A for information about intermittent
diagnosis. Follow procedures for basic circuit testing in
service manual section 8A.
What resources you should use
Whenever appropriate, you should use the following
resources to assist in the diagnostic process:
Service manual
Bulletins
Digital multimeter (with a MIN/MAX feature)
Tech II and Tech II upload function
Circuit testing tools (including connector kits/
harnesses and jumper wires)
Ex perience
Intermittent problem solving simulation methods
Customer complaint check sheet
Symptom Simulation Tests
1. Vibration
This method is useful when the customer complaint
analysis indicates that the problem occurs when the
vehicle/system undergoes some form of vibration.
For connectors and wire harness, slightly shake
vertically and horizontally. Inspect the connector joint
and body for damage. Also, tapping lightly along a
suspected circuit may be helpful.For parts and sensors, apply slight vibration to the part
with a light tap of the finger while monitoring the system
for a malfunction.
2. Heat
This method is important when the complaint suggests
that the problem occurs in a heated environment. Apply
moderate heat to the component with a hair drier or
similar tool while monitoring the system for a
malfunction.
CA UTION: Care must be take to avoid overheating
the component.
3. Water and Moisture
This method may be used when the complaint suggests
that the malfunction occurs on a rainy day or under
conditions of high humidity. In this case, apply water in a
light spray on the vehicle to duplicate the problem.
CA UTION: Care must be take to avoid directly
exposing electrical connections to water.
4. Electrical loads
This method involves turning systems ON (such as the
blower, lights or rear window defogger) to create a load
on the vehicle electrical system at the same time you
are monitoring the suspect circuit/component.
5e. Vehicle Operates as Designed
This condition refers to instances where a system
operating as designed is perceived to be unsatisfactory
or undesirable. In general, this is due to:
A lack of understanding by the customer
A conflict between customer ex pectations and
vehicle design intent
A system performance that is unacceptable to the
customer
What you should do
You can verify that a system is operating as designed
by:
Reviewing service manual functional/diagnostic
checks
Ex amining bulletins and other service information for
supplementary information
Compare system operation to an identical vehicle
If the condition is due to a customer misunderstanding
or a conflict between customer ex pectation and system
operation, you should ex plain the system operation to
the customer.
If the complaint is due to a case of unsatisfactory
system performance, you should contact Technical
Assistance for the latest information.
What resources you should use
Whenever possible, you should use the following
resources to facilitate the diagnostic process:

6E–254 ENGINE DRIVEABILITY AND EMISSIONS
DETONATION/SPARK KNOCK SYMPTOM
DEFINITIONS: A mild to severe ping, usually worse under acceleration. The engine makes a sharp metallic knocking
sound that changes with throttle opening. Prolonged detonation may lead to complete engine tailure.
Step Action Value(s) Yes No
1Was the “On-Board Diagnostic (OBD) System Check”
performed?—Go to Step 2Go to 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 visual/physical check performed?
—Go to Step 4Go 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 5Verify repair
5 1. Check for obvious overheating problems:
Low engine coolant
Restricted air flow to radiator
Incorrect coolant solution
2. If a problem is found, repair as necessary.
Was a problem found?—Verify repair Go to Step 6
6 Check the fuel pressure. Refer to 6E-108 page “Fuel
System Diagnosis” .
Was a problem found?—Verify repair Go to Step 7
7 1. Using a Tech 2, display the MAP sensor value in
comparison with atmosphere temperature.
2. Check for a faulty, plugged, or incorrectly installed
MAP sensor.
Was the problem found?—Verify repair Go to Step 8
8 1. Using a Tech 2, display the ECT sensor and IAT
sensor value and warm up condition compared
with the typical data.
2. Check the specified value or wire.
Was the problem found?—Verify repair Go to Step 9
9 Observe the throttle position display on the Tech 2
while slowly increasing throttle pedal.
Does the throttle position increase steady with
increasing smoothly?
—Go to Step 10Refer to
Diagnostic
Trouble Code
P0123 for
further
diagnosis
10 Check the knock sensor wire, shield wire, or
installation condition.
Was a problem found?—Verify repair Go to Step 11
11 Check items that can cause the engine to run lean.
Refer to DTC P1171 “Fuel Supply System Lean
During Power Enrichment”.
Was a problem found?—Verify repair Go to Step 12

ENGINE EXHAUST 6F-3





























When inspecting or replacing exhaust system components,
make sure there is adequate clearance from all points on the
underbody to prevent overheating the floor pan and possible
damage to the passenger compartment insulation and trim
materials.
Check complete exhaust system and nearby body areas and
rear compartment lid for broken, damaged, missing or
mispositioned parts, open seams, holes, loose connections or
other deterioration which could permit exhaust fumes to seep
into the rear compartment or passenger compartment. Dust or
water in the rear compartment may be an indication of a
problem in one of these areas. Any faulty areas should be
corrected immediately.
Hangers
Various types of hangers are used to support exhaust
system(s). These include conventional rubber straps, rubber
rings, and rubber blocks.
The installation of exhaust system supports is very important,
as improperly installed supports can cause annoying vibrations
which can be difficult to diagnose.
Three Way Catalytic Converter (If applicable)
The three way catalytic converter is an emission control device
added to the exhaust system to reduce pollutants from the
exhaust gas stream.

CAUTION: The catalytic converter requires the use of
unleaded fuel only.
Periodic maintenance of the exhaust system is not required. If
the vehicle is raised for other service, it is advisable to check
the condition of the complete exhaust system.
A dual bed monolith catalytic converter is used in combination
with three way catalytic converter.
Catalytic Types:
Three way (Reduction/Oxidation) catalyst
The catalyst coating on the three way (reduction) converter
contains platinum and rhodium which lowers the levels of
nitrous oxide (NOx) as well as hydrocarbons (HC) and carbon
monoxide (Co).
Gasket
The gasket must be replaced whenever a new exhaust pipe,
muffler or catalytic converter is installed.

7A2-4 DIAGNOSIS (JR405E)
PAGE
NO. D3: GEAR SHIFT POINT IS LOW OR HIGH AT ALL POINT................................. 7A2-120
NO. D4: GEAR SHIFT POINT IS LOW OR HIGH AT LIMITED POINT ......................... 7A2-120
NO. D5: NO KICK-DOWN .............................................................................................. 7A2-120
NO. E1: NO GEAR SHIFT .............................................................................................. 7A2-121
NO. E2: ONLY 4TH GEAR (O/D) IS NOT SELECTABLE ............................................. 7A2-124
NO. E3: GEAR IS SHIFTED 2ND TO 3RD IN 2 RANGE ............................................... 7A2-126
NO. E4: GEAR IS SHIFTED 1ST TO 2ND IN L RANGE................................................ 7A2-126
NO. E5: GEAR IS SHIFTED 3RD TO 4TH IN 3 RANGE................................................ 7A2-126
NO. F1: LOW MAXIMUM SPEED OR POOR ACCELERATION ................................... 7A2-127
NO. F2: ENGINE RACES UP DURING ACCELERATION (SLIP) ................................. 7A2-130
NO. F3: NOISE OR VIBRATION DURING THE RUNNING IN R, D, 3, 2 OR L
RANGE .......................................................................................................................... 7A2-130
NO. F4: ENGINE BRAKE DOES NOT APPLY IN L RANGE......................................... 7A2-130
NO. F5: ENGINE STALLS BEFORE VEHICLE STOPS FROM RUNNING ................... 7A2-131
NO. G1: VEHICLE MOVES IN P RANGE OR PARKING GEAR IS NOT
DISENGAGED OTHER THAN P RANGE ..................................................................... 7A2-131
NO. G2: CREEP FORCE IS LARGE.............................................................................. 7A2-131
NO. G3: CREEP FORCE IS SMALL .............................................................................. 7A2-132
NO. G4: LARGE NOISE DURING IDLING WITH THE VEHICLE IN STOP STATE ...... 7A2-133
NO. H1: JUDDER OCCURS AT THE LOCK-UP ........................................................... 7A2-133
NO. H2: LARGE LOCK-UP SHOCK .............................................................................. 7A2-133
NO. H3: LOCK-UP POINT IS HIGH OR LOW ............................................................... 7A2-133
NO. I1: NO LOCK-UP .................................................................................................... 7A2-134
NO. J1: OIL LEAKS FROM BREATHER ....................................................................... 7A2-136
NO. J2: OIL LEAKS BETWEEN ENGINE AND CONVERTER HOUSING .................... 7A2-136
NO. J3: OIL LEAKS BETWEEN MAIN CASE AND CONVERTER HOUSING.............. 7A2-136
NO. J4: OIL LEAKS BETWEEN MAIN CASE AND REAR HOUSING .......................... 7A2-136
NO. J5: OIL LEAKS FROM OIL PAN ............................................................................ 7A2-136
NO. J6: OIL LEAKS FROM MANUAL SHAFT OIL SEAL ............................................. 7A2-136
NO. J7: OIL LEAKS FROM OIL COOLER PIPE JOINT................................................ 7A2-136
NO. Z1: TRANSMISSION OVERHEAT .......................................................................... 7A2-136
NO. Z2: MODE LAMP (POWER DRIVE OR 3RD START) DOES NOT LIGHT UP
WHEN THE POWER MODE OR 3RD START MODE IS TURNED ON........................ 7A2-137

DIAGNOSIS (JR405E) 7A2-91
SYMPTOM DIAGNOSIS

Symptom Condition Description
Oil Leak Breather Oil leaks from breather. J1
Between engine and converter housing Oil leaks between engine and converter
housing. J2
Between converter housing and main caseOil leaks between converter housing and
main case. J3
Between main case and rear housing Oil leaks between main case and rear
housing. J4
Oil pan Oil leaks from oil pan. J5
Manual shaft oil seal Oil leaks from manual shaft oil seal. J6
Oil cooler pipe Oil leaks from oil cooler pipe joint. J7
Other Transmission overheat You smell the transmission burning. Z1

The transmission smokes.
Mode lamp does not light up when the
power mode or 3rd start mode is turned on
The mode lamp on the instrument panel
does not light up though the power mode or
3rd start mode is turned on with the ignition
switch in ON position.
Z2
Mode lamp lights up when the power mode
or 3rd start mode is turned off
The mode lamp on the instrument panel
lights up though the power mode or 3rd start
mode is turned off with the ignition switch in
ON position.
Z3
Oil temperature warning lamp lights up Sometimes, the oil temperature warning
lamp lights up. Z4
Select lever feeling is faulty Select lever feeling is faulty. Z5
Poor fuel consumption Poor fuel consumption. Z6
Pattern select switch is faulty Shift pattern does not change though the
pattern select switch is turned on. Z7
Oil is splashed during the running Oil is splashed during the running. Z8
Abnormal smell Abnormal smell. Z9
Oil quantity is low or high Oil quantity is low or high. Z10
Abnormal oil pressure Oil pressure is low or high. Z11
Reverse buzzer does not ring Reverse buzzer does not ring in R range. Z12

7A2-136 DIAGNOSIS (JR405E)
No. J1: Oil Leaks from Breather

Description:

Oil leaks from breather.

Possible Cause:

ATF quantity is excessively.




No. J2: Oil Leaks Between Engine and Converter Housing
No. J3: Oil Leaks Between Main Case and Converter Housing
No. J4: Oil Leaks Between Main Case and Rear Housing
No. J5: Oil Leaks from Oil Pan
No. J6: Oil Leaks from Manual Shaft Oil Seal
No. J7: Oil Leaks from Oil Cooler Pipe Joint

Description:

Oil leaks between engine and converter housing.

Oil leaks between converter housing and main case.

Oil leaks between main case and rear housing.

Oil leaks from oil pan.

Oil leaks from manual shaft oil seal.

Oil leaks from oil cooler pipe joint.

Possible Cause:

Faulty oil seal or sealing of contact surface is considered.

No. Z1: Transmission Overheat

Description:

You smell the transmission burning.

The transmission smokes.

Possible Cause:

Slip of clutch.
If slip of clutch is caused, a DTC (gear ratio error) is stored.

Clogged oil cooler (foreign substance mixed)

ATF stirred excessively (too much ATF).

Faulty torque converter operating pressure.

Faulty lock-up piston.