1996 TOYOTA LAND CRUISER Workshop Manual

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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V08425
LOCKKNK
E6 Connector
(a) Remove the glove compartment (See page SF− 68).
(b) Disconnect the E6 connector from the ECM.
INSPECTION PROCEDURE
Replace knock sensor.
1 Check continuity between terminal KNK of ECM connector and body ground.
OK:
Check knock sensor (See page SF−61).
Measure
the resistance between terminal KNK of the ECM connec-
tor and body ground.
Resistance: 1 MΩ or higher
Connector being checked is connected.
 Indicates the condition of the connector of ECU during the check.
PREPARATION:
CHECK:
2
Go to step 3.
OK OK
NG
 Indicates the position of the ignition switch during the check.
Check from the connector back side.
(with harness)
Ignition Switch LOCK (OFF) Ignition Switch START
LOCKIgnition Switch ONIgnition Switch ACC
START ON
ACC

 Indicates the place to check the voltage or resistance.
 Indicates the connector position to checked, from the front or back side.
Connector being checked is disconnected.
Check from the connector front side. (without harness)
In this case, care must be taken not to bend the terminals.
E6 Connector
KNK Wire Harness
E6 Connector
KNK
A00255
AB0117
A00265
Inspection Procedure
Use the inspection procedure to determine if
the circuit is normal or abnormal, and, if it is
abnormal, use it to determine whether the
problem is
located in the sensors, actuators,
wire harness or ECU.
−
INTRODUCTION HOW TO TROUBLESHOOT ECU CONTROLLED
SYSTEMSIN−27
1996 LAND CRUISER (RM451U)
(2)
(2)
~
~
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FI0048
FI0047
FI0046
IN05X−13
IN−28−
INTRODUCTION HOW TO TROUBLESHOOT ECU CONTROLLED
SYSTEMS
1996 LAND CRUISER (RM451U)
HOW TO USE THE DIAGNOSTIC
CHART AND INSPECTION
PROCEDURE
1. CONNECTOR CONNECTION AND TERMINAL IN- SPECTION
For troubleshooting, diagnostic trouble code charts or
problem symptom table are provided for each circuit with
detailed inspection procedures on the following pages.
When all the component parts, wire harnesses and con-
nectors of each circuit except the ECU are found to be
normal in troubleshooting, then it is determined that the
problem is in the ECU. Accordingly, if diagnosis is per-
formed without the problem symptoms occurring, refer to
Step 8 to replace the ECU. So always confirm that the
problem symptoms are occurring, or proceed with inspec-
tion while using the symptom simulation method.
The instructions ”Check wire harness and connector” and
”Check and replace ECU” which appear in the inspection
procedure, are common and applicable to all diagnostic
trouble codes. Follow the procedure outlined below
whenever these instructions appear.
OPEN CIRCUIT:
This could be due to a disconnected wire harness, faulty con-
tact in the connector, a connector terminal pulled out, etc.
HINT:
It is rarely the case that a wire is broken in the middle of
it. Most cases occur at the connector. In particular, care-
fully check the connectors of sensors and actuators
Faulty contact could be due to rusting of the connector
terminals, to foreign materials entering terminals or a de-
formation of connector terminals. Simply disconnecting
and reconnecting the connectors once changes the
condition of the connection and may result in a return to
normal operation. Therefore, in troubleshooting, if no ab-
normality is found in the wire harness and connector
check, but the problem disappears after the check, then
the cause is considered to be in the wire harness or con-
nectors.
SHORT CIRCUIT:
This could be due to a contact between wire harness and the
body ground or to a short circuit occurred inside the switch, etc.
HINT:
When there is a short circuit between the wire harness and body
ground, check thoroughly whether the wire harness is caught
in the body or is clamped properly.
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FI7187
IN0379
Sensor SideECU Side
IN0378
Sensor SideECU Side
IN0380
Sensor Side
ECU Side
IN0381
Pull Lightly
Looseness of Crimping
−
INTRODUCTION HOW TO TROUBLESHOOT ECU CONTROLLED
SYSTEMSIN−29
1996 LAND CRUISER (RM451U)
2. CONNECTOR HANDLING
When inserting tester probes into a connector, insert them from
the rear of the connector. When necessary, use mini test leads.
For water resistant connectors which cannot be accessed from
behind, take good care not to deform the connector terminals.
3. CONTINUITY CHECK (OPEN CIRCUIT CHECK)
(a) Disconnect the connectors at both ECU and sensor
sides.
(b) Measure the resistance between the applicable terminals of the connectors.
Resistance: 1 Ω or less
HINT:
Measure the resistance while lightly shaking the wire harness
vertically and horizontally.
4. RESISTANCE CHECK (SHORT CIRCUIT CHECK)
(a) Disconnect the connectors on both ends.
(b) Measure the resistance between the applicable terminals of the connectors and body ground. Be sure to carry out
this check on the connectors on both ends.
Resistance: 1 MΩ or higher
HINT:
Measure the resistance while lightly shaking the wire harness
vertically and horizontally.
5. VISUAL CHECK AND CONTACT PRESSURE CHECK
(a) Disconnect the connectors at both ends.
(b) Check for rust or foreign material, etc. in the terminals of the connectors.
(c) Check crimped portions for looseness or damage and check that the terminals are secured in lock portion.
HINT:
The terminals should not come out when pulled lightly from the
back.
c:::::J
o0
c::=J
o0
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Z17004
Fig. 1
OPENECU
2
Sensor
22 2 1
111 AB
C
Z17005
Fig. 2
ECU
Sensor 21 A
B
C
1
1
22
B04722
Fig. 3
ECU
Sensor
21 A
C 1
1
221
2
1 B1
B2
IN−30−
INTRODUCTION HOW TO TROUBLESHOOT ECU CONTROLLED
SYSTEMS
1996 LAND CRUISER (RM451U)
(d) Prepare a test male terminal and insert it in the female ter-
minal, then pull it out.
NOTICE:
When testing a gold −plated female terminal, always use a
gold −plated male terminal.
HINT:
When the test terminal is pulled out more easily than others,
there may be poor contact in that section.
6. CHECK OPEN CIRCUIT
For the open circuit in the wire harness in Fig. 1, perform ”(a)
Continuity Check” or ”(b) Voltage Check” to locate the section.
(a) Check the continuity. (1) Disconnect connectors ”A” and ”C” and measurethe resistance between them.
In the case of Fig. 2:
Between terminal 1 of connector ”A” and terminal 1
of connector ”C” → No continuity (open)
Between terminal 2 of connector ”A” and terminal 2
of connector ”C” → Continuity
Therefore, it is found out that there is an open circuit
between terminal 1 of connector ”A” and terminal 1
of connector ”C”.
(2) Disconnect connector ”B” and measure the resis- tance between the connectors.
In the case of Fig. 3:
Between terminal 1 of connector ”A” and terminal 1
of connector ”B1” → Continuity
Between terminal 1 of connector ”B2” and terminal
1 of connector ”C” → No continuity (open)
Therefore, it is found out that there is an open circuit
between terminal 1 of connector ”B2” and terminal
1 of connector ”C”.
BE4063
DO
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