D25083
Vibrate Slightly
Shake Slightly
Vibrate
Slightly
D25084
Malfunction
01–26
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INTRODUCTION
HOW TO TROUBLESHOOT ECU CONTROLLED
SYSTEMS
26
Author:
Date:
2002 CAMRY REPAIR MANUAL (RM881U)
SYMPTOM SIMULATION
HINT:
The most difficult case in troubleshooting is when no problem symptoms occurs. In such cases, a thorough
customer problem analysis must be carried out, Then simulate the same or similar conditions and environ-
ment 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 confirming the problem symptoms, he
will tend to overlook something important in the repair operation and make a wrong guess somewhere, which
will only lead to a standstill. For example, for a problem which only occurs when the engine is cold, or for
a problem which occurs due to vibration caused by the road during driving, etc., the problem can never be
determined with the engine hot condition or the vehicle at a standstill. Since vibration, heat or water penetra-
tion (moisture) is a likely cause for the problem which is difficult to reproduce, the symptom simulation tests
introduced here are effective measures in a point that the external causes are applied to the vehicle in a
stationary condition.
Important points in the symptom simulation test:
In the symptom simulation test, the problem symptoms should be confirmed, and the problem area or parts
must also be found out. To do so, narrow down the possible problem circuits according to the symptoms
before starting this test and have a hand–held tester connected beforehand. After that, carry out the symp-
tom simulation test, judging whether the circuit being tested is defective or normal and also confirming the
problem symptoms at the same time. Refer to the problem symptoms table of each system to narrow down
the possible causes of the symptom.
1.
VIBRATION METHOD: When vibration seems to be
the major cause.
(a)
PART AND SENSOR
(1)
Apply slight vibration with a finger to the part of the
sensor considered to be the problem cause and
check that the malfunction occurs.
HINT:
Applying strong vibration to relays may result in open relays.
(b)
CONNECTORS
(1)
Slightly shake the connector vertically and horizon-
tally.
(c)
WIRE HARNESS
(1)
Slightly shake the wire harness vertically and hori-
zontally.
The connector joint and fulcrum of the vibration are
the major areas to be checked thoroughly.
2.
HEAT METHOD: When the problem seems to occur
when the suspect area is heated.
(a)
Heat the component that is the possible cause of the mal-
function with a hair dryer or similar object. Check if the
malfunction occurs.
NOTICE:
Do not heat to more than 60
C (140
F) (Temperature
is limited so as not to damage the components).
Do not apply heat directly to the parts in the ECU.
