1996 TOYOTA LAND CRUISER Cruise control

−
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
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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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Z17007
Fig. 4Sensor 21 A
C
1
1
22B5V
5V
5V
0V
Z17008
Fig. 5
2
1 A
C
1
1
2 2
BSHORT
Z17009
Fig. 6
21 A
C
1
1
22
BSensor ECU
−
INTRODUCTION HOW TO TROUBLESHOOT ECU CONTROLLED
SYSTEMSIN−31
1996 LAND CRUISER (RM451U)
(b) Check the voltage.
In a circuit in which voltage is applied (to the ECU connec-
tor terminal), an open circuit can be checked for by con-
ducting a voltage check.As shown in Fig. 4, with each connector still con-
nected, measure the voltage between body ground
and terminal 1 of connector ”A” at the ECU 5V out-
put terminal, terminal 1 of connector ”B”, and termi-
nal 1 of connector ”C”, in that order.
If the results are:
5V: Between Terminal 1 of connector ”A” and Body Ground
5V: Between Terminal 1 of connector ”B” and Body Ground
0V: Between Terminal 1 of connector ”C” and Body Ground
Then it is found out that there is an open circuit in the wire har-
ness between terminal 1 of ”B” and terminal 1 of ”C”.
7. CHECK SHORT CIRCUIT
If the wire harness is ground shorted as in Fig. 5, locate the sec-
tion by conducting a ”continuity check with ground”.
Check the continuity with ground. (1) Disconnect connectors ”A” and ”C” and measurethe resistance between terminal 1 and 2 of connec-
tor ”A” and body ground.
In the case of Fig. 6:
Between terminal 1 of connector ”A” and body
ground → Continuity (short)
Between terminal 2 of connector ”A” and body
ground → No continuity
Therefore, it is found out that there is a short circuit
between terminal 1 of connector ”A” and terminal 1
of connector ”C”.
BE4066
BE4067
BE4068
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Z17808
Fig. 7Sensor 21 A
B1
C
1
1
221 2
B2
ECU
IN0383
Example
Ground
IN0384
Ground
Ground
ECU Side
W/H Side
IN−32
−
INTRODUCTION HOW TO TROUBLESHOOT ECU CONTROLLED
SYSTEMS
1996 LAND CRUISER (RM451U)
(2) Disconnect connector ”B” and measure the resis-
tance between terminal 1 of connector ”A” and body
ground, and terminal 1 of connector ”B2” and body
ground.
In the case of Fig. 7:
Between terminal 1 of connector ”A” and body
ground → No continuity
Between terminal 1 of connector ”B2” and body
ground → Continuity (short)
Therefore, it is found out that there is a short circuit
between terminal 1 of connector ”B2” and terminal
1 of connector ”C”.
8. CHECK AND REPLACE ECU
First check the ECU ground circuit. If it is faulty, repair it. If it is
normal, the ECU could be faulty, so replace the ECU with a nor-
mal functioning one and check that the symptoms appear.
(1) Measure the resistance between the ECU groundterminal and the body ground.
Resistance: 1 Ω or less
(2) Disconnect the ECU connector, check the ground terminals on the ECU side and the wire harness
side for bend and check the contact pressure.
o
D~~~D~~~
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