cruise control TOYOTA LAND CRUISER 1996 J80 Workshop Manual

IN04S−30
−
INTRODUCTION HOW TO TROUBLESHOOT ECU CONTROLLED
SYSTEMSIN−17
17
Author: Date:
1996 LAND CRUISER (RM451U)
HOW TO TROUBLESHOOT ECU CONTROLLED SYSTEMS
GENERAL INFORMATION
A large number of ECU controlled systems are used in the LAND CRUISER. In general, the ECU controlled
system is considered to be a very intricate system requiring a high level of t\
echnical knowledge and expert
skill to troubleshoot. However, the fact is that if you proceed to inspect the circuits one by one, trou\
bleshoot-
ing of these systems is not complex. If you have adequate understanding of the system and a basic knowl-
edge of electricity, accurate diagnosis and necessary repair can be performed to locate and fix the pr\
oblem.
This manual is designed through emphasis of the above standpoint to help service techn\
icians perform ac-
curate and effective troubleshooting, and is compiled for the following major ECU con\
trolled systems:
The troubleshooting procedure and how to make use of it are described on\
the following pages.
SystemPage
1. EngineDI−1
2. Automatic TransmissionDI−129
3. Anti− Lock Brake SystemDI−188
4. Supplemental Restraint SystemDI−238
5. Cruise Control SystemDI−284
FOR USING OBD II SCAN TOOL OR TOYOTA HAND−HELD TESTER
Before using the scan tool or tester, the scan tool’ s instruction book or tester’s operator manual should
be read thoroughly.
If the scan tool or tester cannot communicate with ECU controlled systems \
when you have connected
the cable of the scan tool or tester to DLC3, turned the ignition switch\
ON and operated the scan tool,
there is a problem on the vehicle side or tool side.
(1) If communication is normal when the tool is connected to another vehicle, \
inspect the diagnosis data link line (Bus line) or ECU power circuit of the vehicle.
(2) If communication is still not possible when the tool is connected to anoth\
er vehicle, the problem is probably in the tool itself, so perform the Self Test procedures outline in the Tester Operator’s
Manual.
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IN04T−19
Vehicle Brought to Workshop
Customer Problem
Analysis
Symptom Confirmation
and Diagnostic Trouble
Code Check
Symptom Simulation
Diagnostic Trouble
Code Chart
Problem Symptoms Table
Circuit Inspection or Parts
Inspection
Repair
Confirmation Test
End
1
2
4 3
5
6 78 Ask the customer about the conditions and the
environment when the problem occurred.
1
Confirm the symptoms and the problem conditions,
and check the diagnostic trouble codes.
(When the problem symptoms do not appear
during confirmation, use the symptom simulation
method described later on.) 2, 3
Check the results obtained in Step 2, then confirm
the inspection procedure for the system or the part
which should be checked using the diagnostic
trouble code chart or the problem symptoms table. 4, 5, 6
Check and repair the affected system or part in
accordance with the instructions in Step 6. 7
After completing repairs, confirm that the problem
has been eliminated.
(If the problem is not reproduced, perform the
confirmation test under the same conditions and
in the same environment as when it occurred for
the first time.) 8
IN−18−
INTRODUCTION HOW TO TROUBLESHOOT ECU CONTROLLED
SYSTEMS
1996 LAND CRUISER (RM451U)
HOW TO PROCEED WITH TROUBLESHOOTING
Carry out troubleshooting in accordance with the procedure on the following page. Here, only the basic pro-
cedure is shown. Details are provided in Diagnostics section, showing the most\
effective methods for each
circuit. Confirm the troubleshooting procedures first for the relevant circuit before beg\
inning troubleshooting
of that circuit.
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Important Points in the Customer Problem Analysis
 What −−−−− Vehicle model, system name
 When −−−−− Date, time, occurrence frequency
 Where −−−−− Road conditions
 Under what conditions? −−−−− Running conditions, driving conditions, weather conditions
 How did it happen? −−−−− Problem symptoms
(Sample) Engine control system check sheet.
ENGINE CONTROL SYSTEM Check Sheet
Customer’s Name
Driver’s Name
Data Vehicle
Brought in
License No.
Model and Model
Year
Frame No.
Engine Model
Odometer Reading
km
miles
Problem Symptoms
Engine does
not Start
Difficult to
Start
Poor Idling
Poor
Drive ability
Engine Stall
Others
Engine does not crankNo initial combustionNo complete combustion
Engine cranks slowly
Other
Incorrect first idleIdling rpm is abnormalHigh ( rpm)Low ( rpm)
Rough idling
Other
HesitationBack fireMuffler explosion (after− fire)Surging
Knocking
Other
Soon after startingAfter accelerator pedal depressed
After accelerator pedal released
During A/C operation
Shifting from N to D
Other
Data Problem
ConstantSometimes ( times per day/month)
Inspector’s
Name
CUSTOMER PROBLEM ANALYSIS CHECK
−
INTRODUCTION HOW TO TROUBLESHOOT ECU CONTROLLED
SYSTEMSIN−19
1996 LAND CRUISER (RM451U)
1. CUSTOMER PROBLEM ANALYSIS
In troubleshooting, the problem symptoms must be confirmed accurately an\
d all preconceptions must be
cleared away in order to give an accurate judgment. To ascertain just what the problem symptoms are, it is
extremely important to ask the customer about the problem and the conditions at t\
he time it occurred.
Important Point in the Problem Analysis:
The following 5 items are important points in the problem analysis. Past pr\
oblems which are thought to be
unrelated and the repair history, etc. may also help in some cases, so as much information as possible s\
hould
be gathered and its relationship with the problem symptoms should be corre\
ctly ascertained for reference
in troubleshooting. A customer problem analysis table is provided in Diagnostics section for each system
for your use.
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DIAGNOSTIC TROUBLE CODE CHECK PROCEDURE
Diagnostic Trouble
Code Check (Make a
note of and then clear) Confirmation
of Symptoms
Diagnostic Trouble
Code Check
Problem Condition
Diagnostic Trouble
Code Display Problem symptoms
exist
Same diagnostic
trouble code is
displayed Problem is
still occurring in the diagnostic
circuit
Normal code is
displayed The problem is still occurring in a place
other than in the diagnostic circuit
(The diagnostic trouble code displayed
first is either for a past problem or it is a
secondary problem)
No problem
symptoms exist
The problem occurred in the diagnostic
circuit in the past
Normal Code Display Problem symptoms
existNormal code is
displayed The problem is still occurring in a place
other than in the diagnostic circuit
No problem
symptoms exist
Normal code is
displayed The problem occurred in a place other
than in the diagnostic circuit in the past
IN−20−
INTRODUCTION HOW TO TROUBLESHOOT ECU CONTROLLED
SYSTEMS
1996 LAND CRUISER (RM451U)
2. SYMPTOM CONFIRMATION AND DIAGNOSTIC TROUBLE CODE CHECK
The diagnostic system in the LAND CRUISER fulfills various functions. The first functio\
n is the Diagnostic
Trouble Code Check in which a malfunction in the signal circuits to the ECU is stored in co\
de in the ECU
memory at the time of occurrence, to be output by the technician during troubl\
eshooting. Another function
is the Input Signal Check which checks if the signals from various switc\
hes are sent to the ECU correctly.
By using these check functions, the problem areas can be narrowed down qui\
ckly and troubleshooting can
be performed ef fectively. Diagnostic functions are incorporated in the following systems in the LAND CRUIS-
ER.
SystemDiagnostic Trouble
Code CheckInput Signal Check(Sensor Check)Diagnostic Test
Mode (Active Test)
1. Engine
(with Check Mode)
2. Automatic T ransmission
(with Check Mode)
3. Anti− Lock Brake System
4. Supplemental Restraint System
5. Cruise Control System
In diagnostic trouble code check, it is very important to determine whethe\
r the problem indicated by the diag-
nostic trouble code is still occurring or occurred in the past but returned to\
normal at present. In addition,
it must be checked in the problem symptom check whether the malfunction \
indicated by the diagnostic
trouble code is directly related to the problem symptom or not. For this reason, the \
diagnostic trouble codes
should be checked before and after the symptom confirmation to determine the curre\
nt conditions, as shown
in the table below. If this is not done, it may, depending on the case, result in unnecessary troubleshooting
for normally operating systems, thus making it more difficult to locate the problem, or in repairs not pertinent
to the problem. Therefore, always follow the procedure in correct order an\
d perform the diagnostic trouble
code check.
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Diagnostic trouble code check
Making a note of and clearing of the diagnostic trouble codes displayed Symptom confirmation No problem symptoms
exist
Problem symptoms
exist
Simulation test using the symptom
simulation methods
 Normal code displayed
 Problem symptoms exist  Normal code displayed
 No problem symptoms exist
Diagnostic trouble code check
Troubleshooting of problem indicated
by diagnostic trouble code  Diagnostic trouble code displayed
 Problem symptoms exist
System Normal
Troubleshooting of each
problem symptom
If a diagnostic trouble code was
displayed in the initial diagnostic
trouble code check, it indicates
that the trouble may have occurred
in a wire harness or connector in
that circuit in the past. Therefore,
check the wire harness and con-
nectors (See page IN−28).
−
INTRODUCTION HOW TO TROUBLESHOOT ECU CONTROLLED
SYSTEMSIN−21
1996 LAND CRUISER (RM451U)
Taking into account the points on the previous page, a flow chart showing how to proceed with troubleshoot-
ing using the diagnostic trouble code check is shown below. This flow chart shows how to utilize the diagnos-
tic trouble code check effectively, then by carefully checking the results, indicates how to proceed eithe\
r to
diagnostic trouble code troubleshooting or to troubleshooting of problem symptoms \
table.
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V07268
VIBRATION METHOD: When vibration seems to be the major cause.
CONNECTORS
WIRE HARNESS
PARTS AND SENSOR 1
Slightly shake the connector vertically and horizontally.
Slightly shake the wire harness vertically and horizontally.
The connector joint, fulcrum of the vibration, and body
through portion are the major areas to be checked thorough-
ly.
Apply slight vibration with a finger to the part of the sensor
considered to be the pr oblem cause and check that the mal-
function occurs. Shake Slightly
Swing SlightlyVibrate Slightly
HINT:
Applying strong vibration to relays may result in open relays.
IN−22
−
INTRODUCTION HOW TO TROUBLESHOOT ECU CONTROLLED
SYSTEMS
1996 LAND CRUISER (RM451U)
3. SYMPTOM SIMULATION
The most dif ficult case in troubleshooting is when there are no problem symptoms occurring. In such\
cases,
a thorough customer problem analysis must be carried out, then simulate \
the same or similar conditions and
environment in which the problem occurred in the customer’s vehicle. No matter how much experience a
technician has, or how skilled he may be, if he proceeds to troubleshoot without c\
onfirming the problem
symptoms he will tend to overlook something important in the repair operation an\
d make a wrong guess
somewhere, which will only lead to a standstill. For example, for a problem which only occurs \
when the en-
gine is cold, or for a problem which occurs due to vibration caused by the road during\
driving, etc., the prob-
lem can never be determined so long as the symptoms are confirmed with t\
he engine hot condition or the
vehicle at a standstill. Since vibration, heat or water penetration (moisture) is l\
ikely cause for problem which
is difficult to reproduce, the symptom simulation tests introduced here are ef\
fective measures in that the ex-
ternal causes are applied to the vehicle in a stopped condition.
Important Points in the Symptom Simulation Test:
In the symptom simulation test, the problem symptoms should of course be c\
onfirmed, but the problem area
or parts must also be found out. To do this, narrow down the possible problem circuits according to the symp-
toms before starting this test and connect a tester beforehand. After that, \
carry out the symptom simulation
test, judging whether the circuit being tested is defective or normal and also confirming the \
problem symp-
toms at the same time. Refer to the problem symptoms table for each syst\
em to narrow down the possible
causes of the symptom.
FI2331
FI2332
FI2330
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B02389B02390
HEAT METHOD: When the problem seems to occur when the suspect area is heated.
2
NOTICE: 3 WATER SPRINKLING METHOD:
(1)
(2)
4 OTHER: When a malfunction seems to occur when electrical load is excessive. When the malfunction seems to occur on a rainy day or in a
high
−humidity condition.
Heat the component that is the likely cause of the malfunction
with a hair dryer or similar object. Check to see if the
malfunction
occurs.
Sprinkle water onto the vehicle and check to see if the malfunc-
tion occurs.
Turn on all electrical loads including the heater blower, head
lights, rear window defogger, etc. and check to see if the mal-
function occurs. ON
HINT:
If a vehicle is subject to water leakage, the leaked water may
contaminate
the ECU. When testing a vehicle with a water leak-
age problem, special caution must be taken.
Malfunc-
tion
Do not heat to more than 60 °C (140° F). (Temperature
is limited not to damage the components.)
Do not apply heat directly to parts in the ECU.
(1)
(2)
Never sprinkle water directly into the engine compart-
ment, but indirectly change the temperature and hu-
midity by applying water spray onto the radiator front
surface.
Never apply water directly onto the electronic compo-
nents.
NOTICE:
−
INTRODUCTION HOW TO TROUBLESHOOT ECU CONTROLLED
SYSTEMSIN−23
1996 LAND CRUISER (RM451U)
FI2334
FI6649
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 DTC No.
Indicates the diagnostic trouble code.
 Page or Instructions
Indicates the page where the inspection procedure
for each circuit is to be found, or gives instructions
for checking and repairs. Detection Item
Indicates the system of the problem or
contents of the problem.  Trouble Area
Indicates the suspect area of the
problem.
Mass
Air Flow Circuit MalfunctionDetection Item
 Open or short in mass air flow meter circuit
 Mass air flow meter
 ECM
DTC No.
(See page)
Trouble Area
MIL* MemoryP0100
(DI−24)
P0101
(DI−28)
P0115
(DI−33)  Open or short in intake air temp. sensor
circuit
 Intake air temp. sensor
 ECM
Intake Air Temp. Circuit
Malfunction
P0110
(DI−29)
 Open or short in engine coolant temp. sensor circuit
 Engine coolant temp. sensor
 ECM
Throttle/ Pedal Position Sensor/Switch
”A” Circuit MalfunctionEngine Coolant Temp.
Circuit Malfunction
 Open or short in throttle position sensor circuit
 Throttle position sensor
 ECM
HINT:
Parameters listed in the chart may not be exactly the same as your readi\
ng due to the type of instrument or other
factors.
If a malfunction code is displayed during the DTC check mode, check the circ\
uit for the code listed in the table
below. For details of each code, turn to the page referred to under the ”See\
page” for the respective ”DTC No.”
in the DTC chart.
Mass Air Flow Circuit
Range/ Performance Problem Mass air flow meter
 Throttle position sensor
Throttle/
Pedal Position Sensor/ Switch
”A” Circuit Range / Performance Prob-
lem
P0116
(DI−37)
Engine Coolant Temp.
Circuit
Range/ Performance Problem Engine coolant temp. sensor
 Cooling system
SAE CONTROLLED
DIAGNOSTIC TROUBLE CODE CHART
IN−24−
INTRODUCTION HOW TO TROUBLESHOOT ECU CONTROLLED
SYSTEMS
1996 LAND CRUISER (RM451U)
4. DIAGNOSTIC TROUBLE CODE CHART
The inspection procedure is shown in the table below. This ta ble permits efficient and accurate troubleshoot-
ing using the diagnostic trouble codes displayed in the diagnostic trouble code check. Proceed with trouble-
shooting in accordance with the inspection procedure given in the diagnostic cha\
rt corresponding to the
diagnostic trouble codes displayed. The engine diagnostic trouble code chart is sho\
wn below as an example.
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−
INTRODUCTION HOW TO TROUBLESHOOT ECU CONTROLLED
SYSTEMSIN−25
1996 LAND CRUISER (RM451U)
5. PROBLEM SYMPTOMS TABLE
The suspected circuits or parts for each problem symptom are shown in th\
e table below. Use this table to
troubleshoot the problem when a ”Normal” code is displayed in the \
diagnostic trouble code check but the
problem is still occurring. Numbers in the table indicate the inspection order in which the circuits or parts
should be checked.
HINT:
When the problem is not detected by the diagnostic system even though the pr\
oblem symptom is present,
it is considered that the problem is occurring outside the detection ran\
ge of the diagnostic system, or that
the problem is occurring in a system other than the diagnostic system.
Symptom
Suspected AreaSee page
Engine does not crank (Does not start)
No initial combustion (Does not start)
No complete combustion (Does not start) 1. Starter and starter relay
1. ECM power source circuit
2. Fuel pump control circuit
3. ECM
1. Starter signal circuit
2. Fuel pump control circuit 1. Fuel pump control circuit
DI−147
DI−151
IN−29
PROBLEM SYMPTOMS TABLE
1. Compression
2. Fuel pump control circuit 1. A/C signal circuit
2. Fuel pump control circuit 1. A/C signal circuit (Compressor circuit)
2. ECM power source circuit 1. Starter signal circuit
2. Fuel pump control circuit1. Starter signal circuit
2. Fuel pump control circuit
3. Compression
idling)
High engine idle speed (Poor idling) Hot engine
Cold engine (Difficult to start) Engine cranks normally (Difficult to start)
AC−88 DI−144
DI−151
EM−3 DI−151
 Problem Symptom Page
Indicates the page where the flow chart for each circuit
is located.
 Circuit Inspection, Inspection Order
Indicates the circuit which needs to be checked for each problem
symptom. Check in the order indicated by the numbers.
 Circuit or Part Name
Indicates the circuit or part which needs to be checked.
ST−2
ST−17
DI−144
DI−151
DI−144
DI−151
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V08423
Knock Sensor 1
GR ECM
KNK E1
12
E6
WIRING DIAGRAM
Wiring Diagram
This shows a wiring diagram of the circuit.
Use this diagram together with ELECTRICAL
WIRING DIAGRAM to thoroughly understand the
circuit.
Wire colors are indicated by an alphabetical code.
B = Black, L = Blue, R = Red, BR = Brown,
LG = Light Green, V = Violet, G = Green,
O = Orange, W = White, GR = Gray, P = Pink,
Y = Yellow, SB = Sky Blue
The first letter indicates the basic wire color and
the second letter indicates the color of the stripe.
DTC P0325Knock Sensor 1 Circuit Malfunction
CIRCUIT DESCRIPTION
Knock sensor is fitted to the cylinder block to detect engine knocking. This sensor c\
ontains a piezoelectric element which
generates a voltage when it becomes deformed, which occurs when the cyli\
nder block vibrates due to knocking. If engine
knocking occurs, ignition timing is retarded to suppress it.
DTC No. DTC Detection Condition Trouble Area
P0325 No knock sensor 1 signal to ECM with engine speed,
1,200 rpm or more.  Open or short in knock sensor1 circuit
 Knock sensor 1 (looseness)
 ECM
If the ECM detects the above diagnosis conditions, it operates the fall sa\
fe function in which the corrective retard angle
value is set to the maximum value.
 Diagnostic Trouble Code No. and Detection Item
 Circuit Description
The major role and operation, etc. of the circuit
and its component parts are explained.
 Indicates the diagnostic trouble code, diagnostic
trouble code set parameter and suspect area of
the problem.

IN−26
−
INTRODUCTION HOW TO TROUBLESHOOT ECU CONTROLLED
SYSTEMS
1996 LAND CRUISER (RM451U)
6. CIRCUIT INSPECTION
How to read and use each page is shown below.
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