U.S. patent application number 11/699556 was filed with the patent office on 2007-08-02 for failure diagnostic apparatus and method of storing failure information.
This patent application is currently assigned to Toyota Jidosha Kabushiki Kaisha. Invention is credited to Hiroki Morozumi.
Application Number | 20070180318 11/699556 |
Document ID | / |
Family ID | 38323571 |
Filed Date | 2007-08-02 |
United States Patent
Application |
20070180318 |
Kind Code |
A1 |
Morozumi; Hiroki |
August 2, 2007 |
Failure diagnostic apparatus and method of storing failure
information
Abstract
A failure diagnostic apparatus determines the environment in
which the condition of a vehicle is examined and selects an
appropriate storage location for information regarding the
condition of the vehicle. In particular, the failure diagnostic
apparatus includes a vehicle-condition diagnostic portion, a
plurality of failure-information storage portions, a
diagnostic-environment determination portion, and a storage
selection portion. When the vehicle-condition diagnostic portion
determines that a failure has occurred, the diagnostic-environment
determination portion determines the environment in which the
condition of the vehicle is examined. Then, based on the diagnostic
environment determined by the diagnostic-environment determination
portion, the storage selection portion selects at least one storage
portion of the plurality of failure-information storage portions to
store information regarding the failure.
Inventors: |
Morozumi; Hiroki;
(Toyota-shi, JP) |
Correspondence
Address: |
FINNEGAN, HENDERSON, FARABOW, GARRETT & DUNNER;LLP
901 NEW YORK AVENUE, NW
WASHINGTON
DC
20001-4413
US
|
Assignee: |
Toyota Jidosha Kabushiki
Kaisha
|
Family ID: |
38323571 |
Appl. No.: |
11/699556 |
Filed: |
January 30, 2007 |
Current U.S.
Class: |
714/23 |
Current CPC
Class: |
G07C 5/085 20130101;
G05B 23/0264 20130101; G07C 5/0808 20130101; G07C 2205/02
20130101 |
Class at
Publication: |
714/23 |
International
Class: |
G06F 11/00 20060101
G06F011/00 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 2, 2006 |
JP |
2006-026228 |
Claims
1. A failure diagnostic apparatus, comprising: a vehicle-condition
diagnostic portion that examines the condition of the vehicle to
determine whether a failure has occurred; a plurality of
failure-information storage portions in which, when the
vehicle-condition diagnostic portion determines that a failure has
occurred, information about the failure is stored; a
diagnostic-environment determination portion that determines a
diagnostic environment in which the vehicle-condition diagnostic
portion examines the condition of the vehicle; and a storage
selection portion that selects at least one storage portion of the
plurality of failure-information storage portions to store the
information about the failure, based on the diagnostic environment
determined by the diagnostic-environment determination portion.
2. The failure diagnostic apparatus according to claim 1, wherein
the plurality of failure-information storage portions includes a
volatile storage portion in which the information about the failure
is temporarily stored, and a non-volatile storage portion in which
the information about the failure is permanently stored.
3. The failure diagnostic apparatus according to claim 2, wherein
the storage selection portion prohibits the information about the
failure from being stored in the non-volatile storage portion when
the diagnostic-environment determination portion determines that
the diagnostic environment is a predetermined environment.
4. The failure diagnostic apparatus according to claim 3, wherein
the predetermined environment is a factory or a repair shop.
5. The failure diagnostic apparatus according to claim 1, wherein
the diagnostic-environment determination portion determines whether
the vehicle-condition diagnostic portion examines the condition of
the vehicle when a user is using the vehicle, or the
vehicle-condition diagnostic portion examines the condition of the
vehicle at a factory or a repair shop.
6. The failure diagnostic apparatus according to claim 1, further
comprising: an information determination portion that determines
whether the information about the failure is first information that
is temporarily needed, or second information that is permanently
needed, wherein the plurality of failure-information storage
portions includes a first non-volatile storage portion and a second
non-volatile storage portion; if the information determination
portion determines that the information about the failure is the
first information, the storage selection portion selects the first
non-volatile storage portion; and if the information determination
portion determines that the information about the failure is the
second information, the storage selection portion selects the
second non-volatile storage portion.
7. A failure diagnostic apparatus, comprising: a
failure-determination portion that determines whether a failure has
occurred in the vehicle; a vehicle-environment determination
portion; an information determination portion; and a plurality of
failure-information storage portions, wherein, when the
failure-determination portion determines that the failure has
occurred, the vehicle-environment determination portion determines
an environment around the vehicle and the information determination
portion determines whether information about the failure is first
information that is temporarily needed, or second information that
is permanently needed, based on the determined environment around
the vehicle; and the first information and the second information
are stored in different portions in the plurality of
failure-information storage portions.
8. The failure diagnostic apparatus according to claim 7, wherein
the plurality of failure-information storage portions includes a
volatile storage portion and a non-volatile storage portion, the
first information is stored in the volatile storage portion, and
the second information is stored in the non-volatile storage
portion.
9. A method of storing information about a failure that has
occurred in a vehicle, comprising: examining a condition of a
vehicle to determine whether a failure has occurred; determining a
diagnostic environment in which the condition of the vehicle is
examined; and selecting, when it is determined that a failure has
occurred, a storage location to store information about the
failure, based on the determined diagnostic environment.
Description
INCORPORATION BY REFERENCE
[0001] The disclosure of Japanese Patent Application No. 2006-26228
filed on Feb. 2, 2006 including the specification, drawings and
abstract is incorporated herein by reference in its entirety.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The invention relates to a failure diagnostic apparatus and
a method of storing information failure. More particularly, the
invention relates to a failure diagnostic apparatus and a method of
storing failure information that easily determine the environment
in which the condition of a vehicle is examined.
[0004] 2. Description of the Related Art
[0005] Recently, it has been made mandatory to provide an On-Board
Diagnostic-II (hereinafter, referred to as "OBD-II") system in
vehicles such as automobiles, to prevent air pollution. The OBD-II
system provides a warning to a driver if a failure occurs in an
exhaust gas control device. In the OBD-II system, information
regarding a failure is stored in non-volatile memory of an
Electronic Control Unit (hereinafter, referred to as "ECU").
[0006] More specifically, in the OBD-II system, a Diagnostic
Trouble Code (hereinafter, referred to as "DTC"), which contains
information about a failure, is stored in the non-volatile memory.
The DTC stored in the non-volatile memory is later retrieved using
a scan tool so that the cause of the failure can be determined. The
scan tool is a device dedicated to retrieving the DTC. After the
cause of the failure is determined, and the cause of the failure is
corrected by appropriate repair, the DTC stored in the non-volatile
memory is erased using the erase function of the scan tool.
[0007] Japanese Utility Model Application Publication No. 2-49772
describes an airbag system that includes volatile memory and
non-volatile memory provided in an ECU. The volatile memory or the
non-volatile memory is appropriately selected to store the
information about a failure that occurs in, for example, a
collision detection portion in the airbag system. The response
speed of the volatile memory is high, and the volatile memory is
suitable for temporarily retaining records. Therefore, information
that is frequently updated is stored in the volatile memory. For
example, if a failure time is updated every one second or every one
minute, the information on the failure time is stored in the
volatile memory. In contrast, the non-volatile memory is suitable
for permanently retaining records. Therefore, the information that
is not updated frequently is stored in the non-volatile memory. For
example, if the failure time is updated once every hour, the
failure time is stored in the non-volatile memory.
[0008] Emission regulations tend to be tightened to take further
measures against air pollution. Therefore, further requirements for
the OBD-II system will be set. Particularly, it will be required to
prohibit the DTC stored in the non-volatile memory from being
erased by the scan tool, to more reliably retain the DTC.
[0009] In the system described in the above-described publication,
the DTC about a failure is stored in the non-volatile memory.
Therefore, even if a failure occurs, for example, in an assembly
process when a vehicle is manufactured at a factory, the DTC about
the failure is stored in the non-volatile memory in the same way as
the DTC about the failure that occurred when a driver used the
vehicle. Accordingly, if the DTC is prohibited from being erased in
the OBD-II, the DTC about the failure that occurred when the
vehicle was manufactured at the factory cannot be erased. In this
case, when the DTC is retrieved using the scan tool, it cannot be
determined whether the DTC was stored due to a failure that
occurred when the vehicle was manufactured at the factory, or due
to a failure that occurred when a driver used the vehicle.
SUMMARY OF THE INVENTION
[0010] The invention provides a failure diagnostic apparatus that
easily determines the environment in which the condition of a
vehicle is examined.
[0011] A first aspect of the invention relates to a failure
diagnostic apparatus that includes a vehicle-condition diagnostic
portion, a plurality of failure-information storage portions, a
diagnostic-environment determination portion, and a storage
selection portion. The vehicle-condition diagnostic portion
examines the condition of a vehicle to determine whether a failure
has occurred. In the plurality of failure-information storage
portions, when the vehicle-condition diagnostic portion determines
that a failure has occurred, information about the failure is
stored. The diagnostic-environment determination portion determines
the diagnostic environment in which the vehicle-condition
diagnostic portion examines the condition of the vehicle. The
storage selection portion selects at least one storage portion of
the plurality of failure-information storage portions, based on the
diagnostic environment determined by the diagnostic-environment
determination portion.
[0012] In the first aspect, the plurality of failure-information
storage portions may include a volatile storage portion, and a
non-volatile storage portion. The information about the failure is
temporarily stored in the volatile storage portion. The information
about the failure is permanently stored in the non-volatile storage
portion.
[0013] In the above aspect, when the diagnostic-environment
determination portion determines that the diagnostic environment is
a predetermined environment, the storage selection portion may
prohibit the information about the failure from being stored in the
non-volatile storage portion.
[0014] A second aspect relates to a method of storing failure
information. The method includes examining the condition of a
vehicle to determine whether a failure has occurred; determining
the diagnostic environment in which the condition of the vehicle is
examined; and selecting, when it is determined that a failure has
occurred, a storage location to store information about the
failure, based on the determined diagnostic environment.
[0015] Thus, the invention provides the failure diagnostic
apparatus that easily determines the environment in which the
condition of the vehicle is examined.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] The foregoing and further objects, features and advantages
of the invention will become apparent from the following
description of example embodiments with reference to the
accompanying drawings, wherein like numerals are used to represent
like elements and wherein:
[0017] FIG. 1 is a diagram showing an example of the configuration
of a failure diagnostic apparatus according to the invention;
[0018] FIG. 2 is a flowchart showing a process of storing failure
information in the failure diagnostic apparatus according to the
invention; and
[0019] FIG. 3 is a flowchart showing another process of storing
failure information in the failure diagnostic apparatus according
to the invention.
DETAILED DESCRIPTION OF THE EXAMPLE EMBODIMENTS
[0020] Hereinafter, each of embodiments of the invention will be
described with reference to the accompanying drawings.
[0021] FIG. 1 shows an example configuration of a failure
diagnostic apparatus. The failure diagnostic apparatus 1 includes a
volatile storage portion 10, a non-volatile storage portion 11, a
vehicle-condition diagnostic portion 12, a diagnostic-environment
determination portion 13, and a storage selection portion 14. The
failure diagnostic apparatus is connected to a scan tool 2 via a
communication line such as CAN (Controller Area Network).
[0022] The failure diagnostic apparatus 1 may be provided in at
least one ECU. Alternatively, the failure diagnostic apparatus 1
may be independent of any ECU, and may control at least one ECU via
the communication line such as CAN.
[0023] In the volatile storage portion 10, information about a
failure or an abnormality that occurs in a vehicle (hereinafter,
the information will be referred to as "failure information") is
temporarily stored. For example, the volatile storage portion 10
may be semiconductor memory such as DRAM (Dynamic Random Access
Memory). When supply of electric power to the volatile storage
portion 10 is stopped, records are not retained in the volatile
storage portion 10. In the context of this description, the phrase
"records are not retained in the volatile storage portion 10" does
not include the erasure of the records on purpose from the volatile
storage portion 10.
[0024] In the non-volatile storage portion 11, failure information
is permanently stored. For example, the non-volatile storage
portion 11 may be semiconductor memory such as flash memory. Even
when supply of electric power to the non-volatile storage portion
11 is stopped, records are retained in the non-volatile storage
portion 11.
[0025] The vehicle-condition diagnostic portion 12 examines the
condition of the vehicle. The vehicle-condition diagnostic portion
12 receives signals from, for example, an oxygen sensor, a coolant
temperature sensor, an airflow sensor, and a vacuum sensor. The
oxygen sensor measures the concentration of oxygen in the air
supplied into a combustion chamber. The coolant temperature sensor
measures the temperature of coolant used to cool an engine. The
airflow sensor measures the flow amount of air supplied into the
combustion chamber. The vacuum sensor measures the degree of vacuum
in an inlet manifold. The vehicle-condition diagnostic portion 12
examines, for example, the combustion of fuel based on the signals,
and determines whether a failure has occurred in the engine, and
whether the combustion is abnormal.
[0026] The vehicle-condition diagnostic portion 12 usually examines
the condition of the vehicle when the vehicle is actually in use,
for example, when the vehicle is moving. The vehicle-condition
diagnostic portion 12 is also used to examine the condition of the
vehicle, for example, at a test that is conducted at a factory
before the vehicle is shipped. Further, the vehicle-condition
diagnostic portion 12 is used to examine the condition of the
vehicle for troubleshooting, for example, in a repair shop.
[0027] The diagnostic-environment determination portion 13
determines the environment in which the condition of the vehicle is
examined (hereinafter, referred to as "diagnostic environment").
For example, the diagnostic-environment determination portion 13
determines whether the condition of the vehicle is examined at the
factory before the vehicle is shipped, or the condition of the
vehicle is examined for troubleshooting in the repair shop after
the vehicle has been shipped, or the condition of the vehicle is
examined when the vehicle is actually in use, for example, when the
vehicle is driven on a road.
[0028] The failure diagnostic apparatus 1 operates in a plurality
of diagnostic modes, such as a factory-inspection mode and a
monitoring mode. When the failure diagnostic apparatus 1 operates
in the factory-inspection mode, the vehicle is presumed to be at
the factory or the repair shop. When the failure diagnostic
apparatus 1 operates in the monitoring mode, the vehicle is
actually in use, for example, the vehicle is being driven on a
road. The information about the plurality of diagnostic modes may
be stored in the non-volatile storage portion 11. The
diagnostic-environment determination portion 13 may retrieve the
information about the diagnostic modes from the non-volatile
storage portion 11, and may determine the diagnostic environment
based on the information. The failure diagnostic apparatus 1 may
change the diagnostic modes, add other diagnostic modes, or remove
one or more of the diagnostic modes, using a predetermined device
such as the scan tool 2.
[0029] In the failure diagnostic apparatus 1, the value of a
factory-inspection completion flag may be stored in the
non-volatile storage portion 11. The value of the
factory-inspection completion flag indicates whether a factory
inspection has been completed. In this case, the
diagnostic-environment determination portion 13 retrieves the value
of the factory-inspection completion flag from the non-volatile
storage portion 11, and determines the diagnostic environment based
on the value of the factory-inspection completion flag. In the
failure diagnostic apparatus 1, the value of the factory-inspection
completion flag can be changed using a predetermined device such as
the scan tool 2. The failure diagnostic device 1 may prohibit the
factory-inspection completion flag from being set to "off", which
indicates that the factory inspection has not been completed, after
the flag is set to "on", which indicates that the factory
inspection has been completed. Thus, the value of the
factory-inspection completion flag cannot be easily changed. This
prevents a decrease in the reliability in the determination of the
diagnostic environment.
[0030] In the failure diagnostic apparatus 1, when the number of
times that the power source of the failure diagnostic apparatus 1
is turned on/off is less than a predetermined number of times, the
factory-inspection completion flag may be set to "off". Once the
number of times that the power source is turned on/off has reached
or exceeds the predetermined number of times, the
factory-inspection completion flag may be set to "on". If a failure
occurs immediately after the vehicle is first delivered to the
user, the failure is usually due to, for example, an error in the
installation of a component. By setting the factory-inspection
completion flag based on the number of times that the power source
is turned on/off as described above, a failure that occurs
immediately after the vehicle is first delivered to the user is
regarded as a failure that occurs in the test conducted at the
factory before the vehicle is shipped.
[0031] The storage selection portion 14 selects the storage portion
in which to store the failure information detected by the
vehicle-condition diagnostic portion 12, based on the diagnostic
environment determined by the diagnostic-environment determination
portion 13. For example, if the diagnostic-environment
determination portion 13 determines that the condition of the
vehicle is examined at the factory, the storage selection portion
14 selects the volatile storage portion 10, and prohibits the
failure information from being stored in the non-volatile storage
portion 11. Thus, for example, if a failure due to an error in the
installation of a component is detected at the factory before the
vehicle is shipped, the storage selection portion 14 prevents the
information about the failure from being permanently stored in the
non-volatile storage portion 11.
[0032] If the diagnostic-environment determination portion 13
determines that the condition of the vehicle is examined when the
vehicle is moving, the storage selection portion 14 selects both of
the volatile storage portion 10 and the non-volatile storage
portion 11. For example, all the pieces of failure information
transmitted from the sensors are stored in the volatile storage
portion 10. Then, only the necessary pieces of failure information
are stored in the non-volatile storage portion 11. Thus, the
process of storing the failure information is efficiently
performed. Also, the pieces of failure information, which need to
be analyzed later by the scan tool 2, are reliably stored.
[0033] If the diagnostic-environment determination portion 13
determines that the condition of the vehicle is examined when the
vehicle is running, the same failure information may be stored in
both of the non-volatile storage portion 11 and the volatile
storage portion 10. In this case, by storing the failure
information in both of the volatile storage portion 10 and the
non-volatile storage portion 11, the information can be more
reliably stored in the failure diagnostic apparatus 1.
[0034] If the diagnostic-environment determination portion 13
determines that the condition of the vehicle is examined before the
vehicle is shipped, the storage selection portion 14 may select
only the volatile storage portion 10. If the diagnostic-environment
determination portion 13 determines that the condition of the
vehicle is examined after the vehicle is shipped, the storage
selection portion 14 may select only the non-volatile storage
portion 11. In this case, because the information is not stored in
the volatile storage portion 10 after the vehicle is shipped, the
process of storing the information is simplified. Also, because all
the pieces of the failure information transmitted from the sensors
are stored in the non-volatile storage portion 11, the detailed
failure information, which needs to be analyzed later using the
scan tool 2, can be reliably stored in the failure diagnostic
apparatus 1.
[0035] The scan tool 2 retrieves the failure information stored in
the failure diagnostic apparatus 1. For example, the scan tool 2
retrieves the failure information stored in the volatile storage
portion 10 or the non-volatile storage portion 11 in real time. The
scan tool 2 also retrieves the failure information stored in the
non-volatile storage portion 11 later.
[0036] The phrase "the scan tool 2 retrieves the failure
information in real time" signifies that the scan tool 2 retrieves
the newest failure information when electric power is supplied to
the failure diagnostic apparatus 1 and the failure diagnostic
apparatus 1 receives the signals from the sensors. The phrase "the
scan tool 2 retrieves the failure information later" signifies that
the scan tool 2 retrieves the failure information that was stored
in the non-volatile storage portion 11 in times past, after the
power source of the failure diagnostic apparatus 1 is turned off.
The failure information stored in the non-volatile storage portion
11 is retained even after the power source of the failure
diagnostic apparatus 1 is turned off.
[0037] With this configuration, in the failure diagnostic apparatus
1, the storage portion in which to store the failure information is
selected based on the diagnostic environment. That is, the failure
information is stored in at least one of the volatile storage
portion 10 and the non-volatile storage portion 11, based on the
diagnostic environment. Thus, the environment in which the failure
information is generated can be determined later, using the scan
tool 2.
[0038] Also, in the failure diagnostic apparatus 1, the failure
information generated, for example, at the factory, is not stored
nor retained in the non-volatile storage portion 11. This prevents
the failure information generated at the factory from being
confused with the failure information generated when the vehicle is
in use, in the process of determining the cause of the failure
later. Thus, the cause of the failure can be more reliably
determined later.
[0039] Also, in the failure diagnostic apparatus 1, the failure
information generated, for example, at the factory, is prevented
from being stored in the non-volatile storage portion 11. This
avoids the situation in which the failure information generated at
the factory is retained in the non-volatile storage portion 11, and
the vehicle is regarded as having a failure history after the
vehicle is shipped.
[0040] Next, the flow of the process of storing the failure
information in the volatile storage portion 10 and the non-volatile
storage portion 11 (i.e., failure-information storage portions) in
the failure diagnostic apparatus 1 will be described with reference
to FIG. 2.
[0041] First, the vehicle-condition diagnostic portion 12 examines
the condition of the vehicle to determine whether a failure has
occurred (step S1: vehicle-condition examination step).
[0042] If the vehicle-condition diagnostic portion 12 determines
that no failure has occurred (NO in step S1), the process ends in
the failure diagnostic apparatus 1. If the vehicle-condition
diagnostic portion 12 determines that a failure has occurred (YES
in step S1), the diagnostic-environment determination portion 13
retrieves the information about the diagnostic modes from the
non-volatile storage portion 11, and determines the diagnostic
environment (step S2: diagnostic-environment determination
step).
[0043] If the diagnostic-environment determination portion 13
determines that the monitoring mode is selected, and the condition
of the vehicle is currently examined while the vehicle is moving,
for example, while the vehicle is being driven on a road (YES in
step S2), the storage selection portion 14 selects both of the
volatile storage portion 10 and the non-volatile storage portion 11
so that the failure information is stored in both of the storage
portions 10 and 11 (step S3: storage selection step).
[0044] If the diagnostic-environment determination portion 13
determines that the factory-inspection mode is selected, and the
condition of the vehicle is currently examined at the factory
before the vehicle is shipped, or the repair shop (NO in step S2),
the storage selection portion 14 selects only the volatile storage
portion 10 so that the failure information is stored in the
volatile storage portion 10 (step S4: storage selection step).
[0045] With this configuration, in the failure diagnostic apparatus
1, if the condition of the vehicle is examined at the factory or
the repair shop to determine whether a failure has been corrected,
and the failure information is generated at the factory or the
repair shop, the failure information is stored in the volatile
storage portion 10. If the failure information is generated when
the vehicle is in use in an ordinary manner, the failure
information is stored in the non-volatile storage portion 11. This
prevents the failure information generated at the factory or the
repair shop from being confused with the failure information
generated when the vehicle is used in the ordinary manner. Thus,
the accuracy of analyzing the failure information is improved.
[0046] In the failure diagnostic apparatus 1, only the failure
information generated in a predetermined environment is stored in
the non-volatile storage portion 11, without erasing unnecessary
information in the non-volatile storage portion 11 using the scan
tool 2.
[0047] Also, in the failure diagnostic apparatus 1, when the power
source is turned off, the failure information stored in the
volatile storage portion 10 is not retained.
[0048] Next, the flow of another process of storing the failure
information in the volatile storage portion 10 and the non-volatile
storage portion 11 (i.e., the failure-information storage portions)
in the failure diagnostic apparatus 1 will be described.
[0049] In the process shown in FIG. 3, the diagnostic-environment
determination step (step S12) differs from the
diagnostic-environment determination step (step 2) in the process
shown in FIG. 2. Other steps in the process shown in FIG. 3 are the
same as those in the process shown in FIG. 2. Therefore, the
description will focus on step S12.
[0050] If the vehicle-condition diagnostic portion 12 determines
that the failure has occurred (YES in step S11), the
diagnostic-environment determination portion 13 retrieves, from the
non-volatile storage portion 11, the value of the
factory-inspection completion flag that indicates whether a factory
inspection has been completed, thereby determining the diagnostic
environment (step S12: diagnostic-environment determination
step).
[0051] If the value of the factory-inspection completion flag is
"on" (ON in step S12), the storage selection portion 14 selects
both of the volatile storage portion 10 and the non-volatile
storage portion 11 so that the failure information is stored in
both of the storage portion 10 and 11 (step S13: storage selection
step).
[0052] If the value of the factory-inspection completion flag is
"off" (OFF in step S12), the storage selection portion 14 selects
only the volatile storage portion 10 so that the failure
information is stored in only the volatile storage portion 10 (step
S14: storage selection step).
[0053] With this configuration, in the failure diagnostic apparatus
1, the failure information generated before a certain time point is
stored in only the volatile storage portion 10, and the failure
information generated after the certain time point is stored in
both of the storage portions 10 and 11. This prevents the failure
information generated before the certain time point from being
confused with the failure information generated after the certain
time point. Thus, the accuracy of analyzing the failure information
is improved.
[0054] Although example embodiments of the invention have been
described in detail, the invention is not limited to the
above-described embodiments. Various modifications and changes may
be made to the above-described embodiments without departing from
the scope of the invention.
[0055] For example, in the above-described embodiments, the
failure-diagnostic apparatus 1 includes two failure-information
storage portions, the volatile storage portion 10 and the
non-volatile storage portion 11. At least one of the volatile
storage portion 10 and the non-volatile storage portion 11 is
selected based on the diagnostic environment, and the failure
information is stored in the selected storage portion. However, the
failure diagnostic apparatus 1 may include only the non-volatile
storage portion 11. In this case, at least one of locations in the
non-volatile storage portion 11 is selected based on the diagnostic
environment, and the failure information is stored in the at least
one selected location. With this configuration, the diagnostic
environments can be classified into two or more groups, and the
failure information generated in different groups of environments
can be stored in different locations. Therefore, the volatile
storage portion 10 can be omitted. Even when the failure diagnostic
apparatus 1 includes both of the volatile storage portion 10 and
the non-volatile storage portion 11, failure information may be
stored in at least one location in the non-volatile storage portion
11 based on the diagnostic environment.
* * * * *