Page 28 - Workshop Manual - Aumark (BJ1051)

01-22
Introduction-How to Troubleshoot the Vehicle
Symptom simulation check

Tips:
• The most difficult situation you may encounter in trouble diagnosis and troubleshooting is
that no faults are found. In such a case, you must perform a thorough analysis to customer
complaints, and then simulate the vehicle and environmental conditions when the
malfunction occurred. A maintenance technician, no matter how experienced and skilled
he/she it, will certainly overlook some important information in maintenance operations and
make wrong guesses which will do nothing but leading to a stagnant situation if he/she does
not identify symptoms during trouble diagnosis and troubleshooting. For example, those
problems that may only occur when engine is cold or that are caused by bumpy roads during
vehicle travel will never be found when the engine is hot or the vehicle is stationary.
Vibration, overheat, and water leak (dampness), etc. are also common causes of troubles but
they are difficult to be reproduced, so a symptom simulation check method is described here
for obtaining effective check results by simulating external factors with vehicle parked.
• Key points in symptom simulation:
• First, you must identify symptoms and locate faulty sections or parts. To achieve this, you
should connect a hand-held diagnostic tester first and minimize troubleshooting scope of
the faulty circuit according to symptoms before the symptom simulation check.
• Then, conduct a symptom simulation test to judge whether the circuit tested is
damaged or not and, at the same time, to identify symptoms. Browse symptoms
01 charts of systems in order to narrow scope of possible causes of this symptom.
gentle rocking 1. Vibration method: Used when vibration is
the first cause of the trouble.
(a) Parts and sensors
• Gently rock the suspected sensor with
your fingers and check if the trouble
occurs.
Tip:
Gently rocking a relay may result in its
open.
(b) Connectors
• Gently rock the connector both
horizontally and vertically.
(c) Harnesses
• Gently rock the harness both
horizontally and vertically. Joints of
gentle rocking harnesses and connectors are the main
areas where require careful check.

gentle rocking

2. Heating method: The trouble will always
occur after a suspected area is heated.
(a) Heat the suspected part with such articles as a
blower and check if the trouble occurs.
Notices:
• Never allow heating temperature to
exceed 60℃. Be sure to limit heating
temperature so as to avoid damage to
the part.
• Never heat any part in the control
module directly.

Page 28