IN0253
WRONGCORRECT
IN0252
WRONGCORRECT
IN−6
−
INTRODUCTION REPAIR INSTRUCTIONS
6
Author: Date:
1996 LAND CRUISER (RM451U)
(k) Care must be taken when jacking up and supporting the
vehicle. Be sure to lift and support the vehicle at the prop-
er locations (See page IN−8).
Cancel the parking brake on the level place and
shift the transmission in Neutral (or N position).
When jacking up the front wheels of the vehicle at
first place stoppers behind the rear wheels.
When jacking up the rear wheels of the vehicle at
first place stoppers before the front wheels.
When either the front or rear wheels only should be
jacked up, set rigid racks and place stoppers in front
and behind the other wheels on the ground.
After the vehicle is jacked up, be sure to support it
on rigid racks . It is extremely dangerous to do any
work on a vehicle raised on a jack alone, even for
a small job that can be finished quickly.
(l) Observe the following precautions to avoid damage to the
following parts:
(1) Do not open the cover or case of the ECU unless absolutely necessary. (If the IC terminals are
touched, the IC may be destroyed by static electric-
ity.)
(2) To disconnect vacuum hoses, pull off the end, not the middle of the hose.
(3) To pull apart electrical connectors, pull on the con- nector itself, not the wires.
(4) Be careful not to drop electrical components, such
as sensors or relays. If they are dropped on a hard
floor, they should be replaced and not reused.
(5) When steam cleaning an engine, protect the elec- tronic components, air filter and emission −related
components from water.
(6) Never use an impact wrench to remove or install temperature switches or temperature sensors.
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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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