JP2014120228A - Fault diagnosis device and stop lamp switch with the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fault diagnosis device in which fault diagnosis can be performed by a switch single body, and a stop lamp switch with the same.SOLUTION: The fault diagnosis device comprises: a first sensor which outputs a first signal (stop lamp signal Vs) of which the output level is switched from OFF to ON at a first switching position of a mobile section (magnet in the present embodiment); a second sensor which outputs a second signal (cruise cancel signal Vc) of which the output level is switched from ON to OFF at a second switching position defining an initial position of the magnet as an origin and separated further than the first switching position; a third sensor which outputs a third signal (stroke detection signal Vk) by detecting switching of the first signal (stop lamp signal Vs) and the second signal (cruise cancel signal Vc), respectively; and a fault diagnosis section for diagnosing a fault in the first, second or third sensor on the basis of the first to third signals (Vs, Vc, Vk).

Description

  The present invention relates to a failure diagnosis apparatus and a stop lamp switch including the same.

  2. Description of the Related Art Conventionally, a switch used for turning off a stop lamp, controlling lighting, and the like, and a switch device using the same are mainly known when operating a brake pedal of an automobile (see Patent Document 1).

  In this switch device, a first sensor is provided on a surface facing a magnet mounted on a moving body, a second sensor is provided below this, and the control means detects the magnetism of the magnet using these two sensors. . When a failure occurs in any one of the sensors, this is detected by an ON / OFF signal from the sensor. Thereby, it is supposed that the switch which can detect a failure with a simple structure, and a switch apparatus using the same can be obtained.

JP 2009-123480 A

  However, in this failure diagnosis by the conventional switch device, when a sensor fails, an OFF signal or an ON signal is output regardless of the movement of the magnet. Therefore, if the position of the magnet is not known, it is determined whether or not it is a failure. It was difficult to judge with a single switch. In addition, failure diagnosis is possible using an ECU (Electric Control Unit), but it is difficult to determine which sensor has failed with a signal from a single switch. There was a problem that the vehicle had to travel in a state of being extinguished or lit.

  Accordingly, an object of the present invention is to provide a failure diagnosis device capable of performing failure diagnosis with a single switch and a stop lamp switch having the failure diagnosis device.

[1] In order to achieve the above object, the present invention is based on a first sensor that outputs a first signal whose output level is switched at a first switching position of the moving unit, and an initial position of the moving unit. , A second sensor that outputs a second signal whose output level is switched at a second switching position that is distant from the first switching position, and switching between the first signal and the second signal. A third sensor that detects and outputs a third signal; and a failure diagnosis unit that diagnoses a failure of the first, second, or third sensor based on the first to third signals; There is provided a failure diagnosis apparatus characterized by comprising:

[2] The first signal of the first sensor and the second signal of the second sensor are switching signals of different phases having an equivalence section between the first and second switching positions. There may be a failure diagnosis apparatus according to the above [1], which is characterized.

[3] The third sensor includes a section from an initial position of the moving unit to the first switching position of the first sensor, the equivalency section, and the second sensor of the second sensor. The failure diagnosis apparatus according to [1] or [2] above, wherein the section after the switching position is output as three values.

[4] In order to achieve the above object, the present invention provides a stop lamp switch including the failure diagnosis device according to any one of [1] to [3].

  According to the present invention, it is possible to provide a failure diagnosis device capable of performing failure diagnosis with a single switch and a stop lamp switch having the failure diagnosis device.

FIG. 1 is an overall block diagram including a vehicle failure diagnosis device equipped with a brake device having a stop lamp switch according to the present embodiment. FIG. 2 is a cross-sectional view of a main part of the stop lamp switch according to this embodiment. FIG. 3 shows the relationship between the signals output from the first sensor, the second sensor, and the third sensor and the switching of the magnet position (moving body position) in the stop lamp switch according to the present embodiment. It is a figure. FIG. 4A is a block diagram of a failure diagnosis unit of the failure diagnosis apparatus according to the present embodiment, and FIG. 4B is a list showing the operation conditions. FIG. 5 is a flowchart of failure diagnosis of the failure diagnosis apparatus according to the present embodiment.

[Embodiment]
(Configuration of failure diagnosis device 1 and stop lamp switch 3)
FIG. 1 is an overall block diagram including a vehicle failure diagnosis apparatus 1 equipped with a brake device 2 having a stop lamp switch 3 according to the present embodiment. The stop lamp switch 3 mainly lights the stop lamp 70 based on the first signal (stop lamp signal Vs) output at the first operation position L1 of the magnet 32 for brake operation (brake pedal 20). Further, the cruise control function is canceled based on the second signal (cruise cancel signal Vc) output from the initial position of the magnet 32 at the second operation position L2 that is distant from the first operation position L1 ( Stop).

  The failure diagnosis apparatus 1 outputs a first signal (stop lamp signal Vs) at which the output level is switched from OFF to ON at a first switching position L1 of the moving unit (magnet 20 in the present embodiment). 34 and a second signal (cruise cancel signal Vc) whose output level is switched from ON to OFF at a second switching position L2 that is distant from the first switching position L1 with the initial position of the magnet 20 as a base point. The second sensor 35 detects the switching between the first signal (stop lamp signal Vs) and the second signal (cruise cancel signal Vc), and outputs a third signal (stroke detection signal Vk). 3 sensors 36 and the first, second, or third sensor (34, 35, or 36) based on the first to third signals (Vs, Vc, Vk). Is schematically configured to have a failure diagnosis unit 200 for diagnosing the disabled, the.

  The brake device 2 is, for example, a foot brake mounted on a vehicle that is operated by a passenger's foot. The brake device 2 is schematically configured to include, for example, a brake pedal 20 that is operated by an occupant's foot and a stop lamp switch 3 that outputs a signal corresponding to the movement distance of the brake pedal 20 by the operation. For example, one end of the brake pedal 20 is rotatably supported by the vehicle, the other end is bent toward the occupant, and a plate on which a foot is placed is provided at the other end. The stop lamp switch 3 will be described later.

  The ignition switch 4 can be turned OFF (operation position for turning off the power), ACC (operation position where some electronic devices can be used), ON (operation that can use all electronic devices) by inserting a key into the cylinder and rotating it, for example. Position), START (operation position for starting the engine), etc., and an ignition signal corresponding to the operation position is output.

  The cruise control switch 5 is, for example, a switch that turns on or off a cruise control function mounted on the vehicle. The cruise control function is a function of controlling the drive unit 8 so as to keep the vehicle at a set speed without operating an accelerator pedal, for example.

  The battery 6 supplies electric power to an electronic device of the vehicle. For example, the failure diagnosis apparatus 1 operates with electric power supplied from the battery 6 while being operated to an operation position other than when the ignition switch 4 is in the OFF state. The failure diagnosis device 1 is configured to light the stop lamp 70 when the brake device 2 is operated regardless of the operation position of the ignition switch 4.

  The stop lamp unit 7 is configured to turn on or off the stop lamps 70 arranged in front and rear of the vehicle, for example, according to the operation of the brake device 2.

  The drive unit 8 includes, for example, an engine that generates driving force, and a transmission that converts the driving force of the engine to a predetermined ratio and transmits it to the wheels. The drive unit 8 is controlled by, for example, the vehicle ECU 10 and the cruise control unit 9.

  For example, the cruise control unit 9 is configured to control the drive unit 8 in order to perform a cruise control function. The cruise control unit 9 maintains a predetermined speed based on, for example, a cruise signal output when the cruise control switch 5 is operated, and the cruise control switch 5 is turned off or the brake pedal 20 is operated. Thus, a drive signal for controlling the drive unit 8 is output so as to end the traveling at a constant speed.

  The vehicle speed sensor 9a is configured to detect the speed of the vehicle and output vehicle speed information corresponding to the speed to the vehicle ECU 10, for example.

  The vehicle ECU 10 includes, for example, a central processing unit (CPU) 100, a random access memory (RAM) 101, a read only memory (ROM) 102, and the like. The CPU 100 is, for example, a semiconductor element that performs a predetermined process by reading a program stored in the ROM 102 and executing the program. The RAM 101 is a semiconductor element that temporarily stores calculation results and the like in predetermined processing performed by the CPU 100, for example. The ROM 102 is a semiconductor element that stores programs executed by the CPU 100, for example.

(Configuration of stop lamp switch 3)
FIG. 2 is a cross-sectional view of a main part of the stop lamp switch 3 according to the present embodiment. FIG. 3 shows switching of signals output from the first sensor 34, the second sensor 35, and the third sensor 36 and the magnet position (moving body position) in the stop lamp switch 3 according to the present embodiment. It is the figure shown about the relationship. FIG. 2 shows, for example, the state where the moving member 31 of the stop lamp switch 3 is pushed into the main body 30, that is, the initial position of the moving member 31 before the brake pedal 20 is operated.

  The stop lamp switch 3 is attached to the vehicle such that the tip 311 of the moving member 31 contacts the brake pedal 20, for example. Further, the stop lamp switch 3 is moved, for example, in the direction of the arrow A from the right side to the left side of the paper surface shown in FIG. The stop lamp 70 is turned on. Further, the stop lamp switch 3 is applied with a force in the direction opposite to the arrow A direction from the brake pedal 20, for example.

  For example, as shown in FIG. 2, the stop lamp switch 3 includes a box-shaped main body 30, a moving member 31 movably provided with respect to the main body 30, and a magnetic field generating member provided on the moving member 31. Magnet 32, elastic member 33 that applies elastic force to moving member 31, first sensor 34, second sensor 35, third sensor 36, and connector portion 38 provided in main body 30. In general, it is structured.

  For example, the main body 30 has a cylindrical portion 301 at one end and a connector portion 38 at the other end. Further, the main body 30 has, for example, a partition portion 302 that forms a surface orthogonal to the moving direction (arrow A direction) of the moving member 31 in the main body 30, and partitions the inside of the main body 30 and the connector portion 38. .

  The cylindrical portion 301 has, for example, a through hole, and the rod 310 of the moving member 31 is inserted into the through hole, and the distal end portion 311 of the rod 310 protrudes from the distal end of the cylindrical portion 301. The rod 310 is in contact with the brake pedal 20 and moves according to the operation position of the brake pedal 20.

  The moving member 31 is schematically configured to include, for example, the rod 310 having a shape corresponding to the shape of the through hole of the cylindrical portion 301 and a stopper 312 formed at the end of the rod 310.

  For example, the stopper 312 does not contact the first sensor 34, the second sensor 35, and the third sensor 36 during movement, and has a shape that is larger than the through hole of the cylindrical portion 301. ing. For example, a magnet 32 is attached to the surface of the stopper 312 opposite to the surface on which the rod 310 is formed. Further, for example, an elastic member 33 is provided between the opposite surface and the partition portion 302. Therefore, the moving member 31 receives, for example, the elastic force from the elastic member 33 in the left direction (arrow A direction) from the right side of the sheet of FIG. That is, when the occupant performs a brake operation, the moving member 31 moves in the direction of arrow A by the urging force of the elastic member 33 as the brake pedal 20 moves. Further, after the occupant finishes the brake operation, the moving member 31 is configured to return to the initial position shown in FIG. 2 as the brake pedal 20 moves in the direction opposite to the arrow A direction.

  The magnet 32 is a permanent magnet such as neodymium, for example. The magnet 32 may be an electromagnet. The elastic member 33 is, for example, a coil spring.

  The first sensor 34, the second sensor 35, and the third sensor 36 are magnetic sensors that output, as signals, changes in the magnetic field generated by the magnet 32, for example. That is, the stop lamp switch 3 can detect the movement of the moving member 31 that moves together with the brake pedal 20 in a non-contact manner. As this magnetic sensor, a magnetoresistive sensor (MagneticResistance Sensor), a Hall sensor, etc. are used, for example. As shown in FIG. 3, the first sensor 34 and the second sensor 35 use MR sensors, and output ON and OFF. The third sensor 36 uses a Hall sensor, and outputs three values of outputs 0, 1, and 2 with two threshold values. The first sensor 34, the second sensor 35, and the third sensor 36 are not limited to magnetic sensors, and may be optical sensors, mechanical switches, or the like.

  As shown in FIG. 2, the first sensor 34, the second sensor 35, and the third sensor 36 are provided on a substrate 37 provided in the main body 30, for example.

  As shown in FIG. 2, the first sensor 34 and the second sensor 35 are arranged at intervals of ΔL in the direction in which the magnet 32 moves via the brake pedal 20 and the moving member 31.

  In addition, the third sensor 36 is disposed at an intermediate portion between the first sensor 34 and the second sensor 35 so as to detect the switching between the first sensor 34 and the second sensor 35.

As shown in FIG. 3, the first sensor 34 outputs a stop lamp signal Vs that switches the stop lamp 70 from the OFF state to the ON state at the operation position of the movement distance L ₁ from the initial position of the magnet 32. That is, for example, the first sensor 34 outputs Hi as the stop lamp signal Vs when the stop lamp 70 is turned on, and outputs Lo as the stop lamp signal Vs when the stop lamp 70 is turned off. It is configured as follows. Here, OFF of the stop lamp signal Vs shown in FIG. 3 indicates that a Lo stop lamp signal Vs for turning off the stop lamp 70 is output, and ON means that the stop lamp 70 is turned on. The Hi stop lamp signal Vs is output.

As shown in FIG. 3, the second sensor 35 outputs a cruise cancel signal Vc (Lo) for stopping the cruise control function at the operation position at the movement distance L ₂ from the initial position of the magnet 32. That is, for example, the second sensor 35 outputs Hi as the cruise cancel signal Vc when maintaining the cruise control function, and Lo as the cruise cancel signal Vc when stopping (cancelling) the cruise control function. Is configured to output. Here, the OFF of the cruise cancel signal Vc shown in FIG. 3 indicates that the Lo cruise cancel signal Vc for turning the cruise control function OFF is being output, and ON means that the cruise control function is ON. This shows that the Hi cruise cancel signal Vc to be maintained is output.

As shown in FIG. 3, the movement distance L ₁ is the distance that the magnet 32 has moved from the initial position when the brake pedal 20 is operated to the first operation position necessary for lighting the stop lamp 70. Is shown. The moving distance L _2, the brake pedal 20 is, when operated in the second operating position required to stop the cruise control function, indicates the distance which the magnet 32 is moved from the initial position.

As shown in FIG. 3, the third sensor 36 switches the stop lamp signal Vs from the OFF state to the ON state at the operation position of the movement distance L ₁ from the initial position of the magnet 32, and the movement distance L of the magnet 32. _The switching of the cruise cancel signal Vc from the ON state to the OFF state at the operation position ₂ is detected. That is, the third sensor 36 outputs three values: output ₁ from the initial position of the magnet 32 in the section Δ1 of the movement distance L1, output 0 in the equivalence section ΔL, and output _{2 in} the section Δ2 after the movement distance L2. A stroke detection signal Vk is generated. Note that the equivalency section ΔL is a section in which the stop lamp signal Vs and the cruise cancel signal Vc both output the Hi signal.

  FIG. 4A is a block diagram of the failure diagnosis unit 200 of the failure diagnosis apparatus according to the present embodiment, and FIG. 4B is a list showing the operating conditions.

  The first sensor 34 is connected to the writing circuit 1 (210), the writing circuit 2 (211), and the determination circuit 3 (250), and outputs a stop lamp signal Vs to each of them. The second sensor 35 is connected to the write circuit 3 (212), the write circuit 4 (213), and the determination circuit 3 (250), and outputs a cruise cancel signal Vc to each. The third sensor 36 is connected to the output switching detection circuit 240 and the determination circuit 3 (250), and outputs a stroke detection signal Vk to each.

  The write circuit 1 (210) is connected to the memory 1 (220), and the memory 1 (220) is connected to the determination circuit 1 (230). Similarly, the write circuit 2 (211) is connected to the memory 2 (221), and the memory 2 (221) is connected to the determination circuit 1 (230).

  The write circuit 3 (212) is connected to the memory 3 (222), and the memory 3 (222) is connected to the determination circuit 2 (231). Similarly, the write circuit 4 (213) is connected to the memory 4 (223), and the memory 4 (223) is connected to the determination circuit 2 (231).

  The output switching detection circuit 240 is connected to the write circuit 2 (211), the write circuit 3 (212), the determination circuit 1 (230), and the determination circuit 2 (231), and outputs an output C to each.

  The determination circuit 1 (230) is connected to the writing circuit 1 (210) and the determination circuit 3 (250), and outputs an output A to each. The determination circuit 2 (231) is connected to the write circuit 4 (213) and the determination circuit 3 (250), and outputs an output B to each of them.

  FIG. 5 is a flowchart of failure diagnosis of the failure diagnosis apparatus 1 according to the present embodiment. Hereinafter, based on this flowchart, operation | movement of the failure diagnosis apparatus 1 which concerns on this Embodiment is demonstrated.

  When the operation of the failure diagnosis device 1 starts, the failure diagnosis unit 200 writes the stop lamp signal Vs of the first sensor 34 to the memory 1 (220) by the writing circuit 1 (210) (Step 1).

  Similarly, the cruise cancel signal Vc of the second sensor 34 is written into the memory 4 (223) by the writing circuit 4 (213) (Step 2).

  The output switching detection circuit 240 determines whether the output C is ON. When the output C is ON, the process proceeds to Step 4, and when the output C is not ON, the determination of Step 3 is repeated (Step 3). As shown in FIG. 4B, the output C is ON when the output 1 is switched to the output 2 or when the output 2 is switched to the output 1.

  The stop ramp signal Vs of the first sensor 34 is written to the memory 2 (221) by the writing circuit 2 (211). Further, the cruise cancel signal Vc of the second sensor 34 is written into the memory 3 (222) by the writing circuit 3 (212) (Step 4).

  The determination circuit 1 (230) determines whether the contents of the memory 1 (220) and the memory 2 (221) match. If they match, go to Step 6. If they do not match, the first sensor 34 is operating normally, so the process returns to Step 1 and the failure diagnosis of the first sensor 34 is repeated. Further, since the first sensor 34 is operating normally, the process proceeds to Step 10 and proceeds to failure diagnosis of the third sensor 36 (Step 5).

  When the contents of the memory 1 (220) and the memory 2 (221) are matched by the determination circuit 1 (230), it is determined that the first sensor 34 is out of order. This is because the contents of the memory 2 (221) are signals when the output C is turned on, and the contents of the memory 1 (220) and the memory 2 (221) are reversed in normal operation. Thereby, the output 3 is turned ON, a failure signal is issued, and the determination is completed (Step 9) (Step 6).

  Similarly, the determination circuit 2 (231) determines whether the contents of the memory 3 (222) and the memory 4 (223) match. If they match, go to Step 8. If they do not match, the second sensor 35 is operating normally, so the process returns to Step 2 and the failure diagnosis of the second sensor 35 is repeated. Further, since the second sensor 35 is operating normally, the process proceeds to Step 10 and proceeds to failure diagnosis of the third sensor 36 (Step 7).

  When the contents of the memory 3 (222) and the memory 4 (223) are matched by the determination circuit 2 (231), it is determined that the second sensor 35 is out of order. This is because the contents of the memory 3 (222) are signals when the output C is turned on, and the contents of the memory 3 (222) and the memory 4 (223) are reversed in normal operation. Thereby, the output 4 is turned ON, a failure signal is issued, and the determination is completed (Step 9) (Step 8).

  The determination circuit 3 (250) determines whether or not the value of the third sensor 36 is output 1. When the value of the third sensor 36 is output 1, the process proceeds to Step 11, and when the value of the third sensor 36 is not output 1, the process proceeds to Step 12 (Step 10).

  The determination circuit 3 (250) determines whether the first sensor 34 is OFF and the second sensor 35 is ON. In the case of Yes, all the first to third sensors are determined as normal operations and are ended (Step 15) (Step 11). This is because, as shown in FIG. 3, when the stroke detection signal Vk is in the section Δ1, the state in which the first sensor 34 is OFF and the second sensor 35 is ON is a normal operation. In the case of No, it progresses to Step14.

  The determination circuit 3 (250) determines whether the value of the third sensor 36 is output 2. When the value of the third sensor 36 is output 2, the process proceeds to Step 13, and when the value of the third sensor 36 is not output 2, the determination is ended (Step 15) (Step 12). In the case of No in Step 12, since the stroke detection signal Vk is in the same value section ΔL and the stop lamp signal Vs and the cruise cancel signal Vc are both in the ON state output Hi signal according to FIG. Therefore, the determination is finished.

  The determination circuit 3 (250) determines whether the first sensor 34 is ON and the second sensor 35 is OFF. In the case of Yes, the determination is finished (Step 16) as normal operation for all the first to third sensors (Step 13). This is because, according to FIG. 3, when the stroke detection signal Vk is in the section Δ2, the state in which the first sensor 34 is ON and the second sensor 35 is OFF is a normal operation. In the case of No, it progresses to Step14.

  From Step 11 and Step 13, in the determination circuit 3 (250), the third sensor 36 is determined to be faulty. Thereby, the output 3 and the output 4 are turned ON, a failure signal is issued, and the determination is completed (Step 15) (Step 14).

  The above-described series of failure diagnosis is repeatedly executed until an interruption / stop interrupt signal is input to the failure diagnosis unit 200.

(Effect of embodiment)
The present embodiment has the following effects.
(1) Since the failure diagnosis apparatus 1 and the stop lamp switch 3 according to the present embodiment are configured to have the failure diagnosis unit 200 on the stop lamp switch 3 side, it is necessary to rely on the vehicle-side ECU for failure determination. There is no. Thereby, it becomes possible to improve the reliability.
(2) Similarly, since the failure diagnosis unit 200 is provided on the stop lamp switch 3 side and it is not necessary to rely on the vehicle-side ECU for failure determination, it is not necessary to design determination software for each ECU, thereby reducing development man-hours. Has the effect of being connected.
(3) Even when the stop lamp switch fails, it is possible to determine which sensor has failed. As a result, it is possible to determine whether the stop lamp 70 is turned off or turned on, and the user can ride to the dealer with peace of mind without falling into a malfunction.
(4) By providing the third sensor 36, an accurate failure diagnosis can be performed with a simple configuration. Although the determination cannot be made in the equivalency section ΔL, the brake pedal 20 is not operated at a position corresponding to this section, and the brake pedal 20 is depressed or returned. Therefore, it is possible to perform fault diagnosis without any practical problem during driving of the vehicle.

  As mentioned above, although embodiment of this invention was described, these embodiment is only an example and does not limit the invention which concerns on a claim. These novel embodiments can be implemented in various other forms, and various omissions, replacements, changes, and the like can be made without departing from the scope of the present invention. In addition, not all the combinations of features described in these embodiments are essential to the means for solving the problems of the invention. Furthermore, these embodiments are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 1 ... Fault diagnosis device, 2 ... Brake device, 3 ... Stop lamp switch, 4 ... Ignition switch, 5 ... Cruise control switch, 6 ... Battery, 7 ... Stop lamp part, 8 ... Drive part, 9 ... Cruise control part, 9a ... Vehicle speed sensor, 10 ... Vehicle ECU, 20 ... Brake pedal, 30 ... Main body, 31 ... Moving member, 32 ... Magnet, 33 ... Elastic member, 34 ... First sensor, 35 ... Second sensor, 36 ... Third 38 ... Connector portion, 37 ... Substrate, 70 ... Stop lamp 100 ... CPU, 101 ... RAM, 102 ... ROM,
200 ... Fault diagnosis unit, 210 ... Write circuit 1, 211 ... Write circuit 2, 212 ... Write circuit 3, 213 ... Write circuit 4, 220 ... Memory 1, 221 ... Memory 2, 222 ... Memory 3, 223 ... Memory 4, 230: determination circuit 1, 231: determination circuit 2, 240: output switching detection circuit, 250: determination circuit 3
301 ... cylindrical portion 302 ... partitioning portion 310 ... rod 311 ... tip portion 312 ... stopper 360 ... terminal

Claims (4)

A first sensor that outputs a first signal whose output level is switched at a first switching position of the moving unit;
A second sensor that outputs a second signal whose output level is switched at a second switching position that is based on the initial position of the moving unit and is separated from the first switching position;
A third sensor for detecting a switching between the first signal and the second signal and outputting a third signal;
A failure diagnosis unit for diagnosing a failure of the first, second, or third sensor based on the first to third signals;
A failure diagnosis apparatus comprising:   The first signal of the first sensor and the second signal of the second sensor are different phase switching signals having an equivalence interval between the first and second switching positions. The failure diagnosis apparatus according to claim 1, wherein the apparatus is a failure diagnosis apparatus.   The third sensor includes a section from an initial position of the moving unit to the first switching position of the first sensor, the equivalency section, and a section after the second switching position of the second sensor. The fault diagnosis apparatus according to claim 1, wherein the fault diagnosis apparatus outputs three values.   A stop lamp switch comprising the failure diagnosis device according to any one of claims 1 to 3.

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