JPH10220571A - Control method and control device for automatic transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To judge the failure of a detecting means accurately and positively by judging the failure of the detecting means for detecting the rotation of a rotating member from the input state of electric signals in a gear speed stage where the electric signals are inputted to at least two shift control solenoids. SOLUTION: At the time of detecting the failure of an input rotation sensor 21 serving as a detecting means, in case of confirming a gear speed stage to be the second gear speed by an electronic control unit 30, whether there is input from the input rotation sensor 21 while there is four-pulse input from an output rotation sensor 22 is checked. In the negative case, 1 is added to failure detecting counter (n) in a counter, and whether (n) is 500 is checked. In case of reaching 500, the failure is determined. A judging means 6 judges the failure of the input rotation sensor 21 from the corresponding relation between a detection signal of the input rotation sensor 21 and the input state of electric signals to shift control solenoids 41, 42 monitored by a monitoring means 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a shift control solenoid for controlling the speed change of at least two shift control solenoids, a detecting means for detecting a rotation of a rotating member as a detected means in an automatic transmission, and In a control method and a control device for an automatic transmission in which the rotating member does not rotate at a shift speed at which no electric signal is input, the electric control at a shift speed at which an electrical signal is input to at least two shift control solenoids. The present invention relates to a control method and a control device for an automatic transmission that determines a failure of the detection unit accurately and reliably by determining a failure of the detection unit based on a signal input state.

[0002]

2. Description of the Related Art A conventional method and apparatus for controlling an automatic transmission is a method for detecting a failure of an input rotation sensor mounted on the outer periphery of a CO clutch. One of the solenoids shown in FIG. In the first to third speeds, if there is no output from the input rotation sensor despite the output from the output rotation sensor of the automatic transmission to the computer, it is determined that the input rotation sensor has failed. Was to do.

[0003]

The above-described conventional method and apparatus for controlling an automatic transmission are characterized in that the output from the input rotation sensor and the output from the output rotation sensor of the automatic transmission at the first to third speeds. There is a problem that a failure of the input rotation sensor cannot be detected accurately only by comparing outputs.

[0004] The above-mentioned problem is caused when one of the two solenoids S1 and S2 for controlling the shift stops functioning due to an electrical failure or a mechanical failure or the like, and the shift speed commanded by the computer and the actual automatic transmission. Is different from that of the first gear.

That is, for example, when the solenoid S1 is turned off due to a failure of the solenoid S1 in the first speed when the solenoid S1 is turned on and the solenoid S2 is turned off at the computer commanded gear, the solenoid S1 and the solenoid S2 are turned off. Since the speed is high and the CO clutch does not rotate, the output from the input rotation sensor cannot be obtained regardless of the failure of the solenoid S1, so the computer erroneously determines that the input rotation sensor has failed. Resulting in.

Similarly, at the third gear position when the solenoid S1 is turned off and the solenoid S2 is turned on at the third command speed, the solenoid S2 is turned off due to a failure of the solenoid S2.
When the solenoid 2 is turned off, the solenoid S1 and the solenoid S2 are in the off state of the fourth speed, and the CO clutch does not rotate. Therefore, the output from the input rotation sensor is not actually obtained regardless of the failure of the solenoid S1. Therefore, as described above, the computer erroneously determines that the input rotation sensor has failed.

Therefore, the inventor of the present invention has proposed that at least two shift control solenoids control a shift, a detecting means detects a rotation of a rotating member as a detected means in the automatic transmission, and any of the shift control solenoids. In a control method for an automatic transmission in which the rotating member does not rotate at a shift speed where an electric signal is not input, an input state of the electric signal at a shift speed at which an electrical signal is input to at least two shift control solenoids The present invention focuses on the first technical idea of the present invention to determine the failure of the detection means, and monitors the input state of an electric signal from the computer to the shift control solenoid, thereby detecting the detection signal and the monitoring. The failure of the detection means is determined based on the correspondence with the input state of the electric signal to the shift control solenoid. Focuses on the second technical idea of the invention, further research and development a result of intensive, have reached the present invention to achieve the object of determining the failure of accurately and reliably the detecting means.

[0008]

According to a first aspect of the present invention, there is provided a method of controlling an automatic transmission, wherein at least two shift control solenoids control a shift, and a detecting unit detects an automatic shift. In a method for controlling an automatic transmission in which the rotation member is not rotated at a gear position in which an electric signal is not input to any of the transmission control solenoids, the rotation of the rotation member as detected means in the machine is detected. A failure of the detection means is determined based on an input state of the electric signal at a gear at which an electric signal is input to the shift control solenoid.

The present invention (the second invention described in claim 2)
In the control method for an automatic transmission according to the first aspect of the present invention, a failure of the detection means is determined based on an input state of an electric signal at a second shift speed.

The present invention (the third invention described in claim 3)
In the control method for an automatic transmission according to the second aspect, the detecting means detects rotation of a friction engagement element of the automatic transmission.

The present invention (the fourth invention described in claim 4)
The control device for an automatic transmission outputs a detection means for detecting rotation of a rotating member as a detected means in the automatic transmission, and an electric signal for controlling the automatic transmission based on a detection signal from the detection means. A computer, and at least two controls for shifting based on electrical signals from the computer
A control unit for an automatic transmission comprising a plurality of shift control solenoids, wherein monitoring means for monitoring an input state of an electric signal from the computer to the shift control solenoid;
Determining means for determining a failure of the detection means based on a correspondence relationship between a detection signal from the detection means and an input state of an electric signal to the shift control solenoid monitored by the monitoring means;

The present invention (the fifth invention described in claim 5)
The control device for an automatic transmission according to the fourth aspect, wherein the determination unit is configured to detect the detection unit based on an input state of the electric signal in a gear at which an electric signal is input to at least two of the shift control solenoids. Is determined.

The present invention (the sixth invention described in claim 6)
In the control device for an automatic transmission according to the fifth aspect, the monitoring means monitors an input state of an electric signal from the computer to the shift control solenoid at a second shift speed.

The present invention (seventh invention described in claim 7)
In the control device for an automatic transmission according to the sixth aspect, the rotating member is a friction engagement element of the automatic transmission.

[0015]

According to the first aspect of the present invention, there is provided a method for controlling an automatic transmission, comprising the steps of: inputting an electric signal to at least two of the shift control solenoids at a shift speed where the electric signal is input; Since the failure of the detection means is determined, the effect of accurately and reliably determining the failure of the detection means is achieved.

According to a second aspect of the present invention, there is provided a control method for an automatic transmission according to the first aspect, wherein the electric signal is input to the two shift control solenoids at the second shift speed. Since the failure of the detection means is determined based on the input state, the effect of preventing erroneous detection of the failure of the detection means due to the failure of the solenoid is achieved.

According to a third aspect of the present invention, there is provided a control method for an automatic transmission, wherein the detecting means comprises:
Since the rotation of the friction engagement element of the automatic transmission is detected,
This has the effect of enabling failure detection of the detection means while the friction engagement element of the automatic transmission is rotating.

The control device for an automatic transmission according to the fourth aspect of the present invention is configured such that, even when one of the solenoids is electrically or mechanically broken, the rotating member as the detected means is constantly rotating. The monitoring means monitors an input state of an electrical signal from the computer to the shift control solenoid, and the determining means determines a detection signal from the detection means and an electric signal to the shift control solenoid monitored by the monitoring means. Since the failure of the detection means is determined based on the correspondence relationship with the input state of the target signal, the effect of accurately and reliably detecting the failure of the detection means is achieved.

According to a fifth aspect of the present invention, in the control device for an automatic transmission according to the fourth aspect, the judging means comprises:
Since the failure of the detecting means is determined based on the input state of the electric signal at the speed at which the electric signal is inputted to at least two of the shift control solenoids, the failure of the detecting means is accurately and reliably detected. It works.

According to a sixth aspect of the present invention, there is provided a control device for an automatic transmission according to the fifth aspect, wherein the monitoring means comprises:
Since the input state of the electric signal from the computer to the shift control solenoid is monitored at the second shift stage where the electric signal is input to the two shift control solenoids, the failure of the detection means can be accurately and reliably detected. This has the effect of detecting the

According to a seventh aspect of the present invention, there is provided the automatic transmission control device according to the sixth aspect, wherein the rotating member comprises:
Since the friction engagement element of the automatic transmission is used, it is possible to detect a failure of the detection unit when the friction engagement element of the automatic transmission is rotating.

[0022]

Embodiments of the present invention will be described below with reference to the drawings.

(First Embodiment) A control device and a control method for an automatic transmission according to a first embodiment of the present invention, as shown in FIGS. Detecting means 2 for detecting rotation, a computer 3 for outputting an electrical signal for controlling the automatic transmission based on a detection signal from the detecting means 2, and a computer 3
In a control device for an automatic transmission comprising two shift control solenoids 41 and 42 for controlling a shift based on an electric signal from the computer 3, an input state of an electric signal from the computer 3 to the shift control solenoids 41 and 42 Monitoring means 5 for monitoring the speed change control solenoid 4 monitored by the detection means 2 and the monitoring means 5
And a judgment unit 6 for judging a failure of the detection unit 2 based on a correspondence relationship with an input state of an electric signal to the first and the second 42.

The automatic transmission A comprises a solenoid valve 41, 42 for shifting, a solenoid valve 43 for a lock-up clutch, and a solenoid valve 44 for an accumulator back pressure in the hydraulic control unit 4 for the automatic transmission constituting the computer 3. Electronic control unit (EC
U) 30.

As shown in FIG. 2, a shift valve 12 operated by a shift lever 11 operates a manual valve (not shown) to set a predetermined gear position.

The electronic control unit 30 has a central processing element (CPU), storage elements (ROM, RAM) and an input / output interface as main components, and includes a vehicle speed sensor 23, a throttle opening sensor 2
4, a brake sensor 25, a pattern sensor 26, an input rotation sensor 21 for detecting rotation of a clutch CO which is a frictional engagement element as the rotating member 10 as the detection means 2, and an output rotation sensor 2.
2 etc. are connected.

The electronic control unit 30 receives various signals such as a vehicle speed V, a throttle opening θ, a brake signal, a pattern select signal, and the like, and sets each gear position according to an automatic shift mode driving state. Solenoid valve 4
1, 42 and the input shaft IS
This detects the failure of the input rotation sensor 21 based on the rotation of the output shaft OS and the rotation of the output shaft OS.

An example of the gear train in the automatic transmission A is as shown in FIG. 1. FIG. 3 shows a main circuit portion of the hydraulic control device 4 for executing a gear shift for this gear train. It is on the street.

The automatic transmission A has a second transmission section OD having a set of planetary gear mechanisms rotationally connected to a torque converter having a lock-up clutch as shown in FIG.
And a first transmission portion T for setting a plurality of forward speeds and reverse speeds by two sets of planetary gear mechanisms.

The second transmission portion OD switches between high and low stages. A carrier PCO of a planetary gear mechanism is connected to a turbine runner of the torque converter. A clutch CO and a one-way clutch FO are provided between the sun gear SO and the housing Hu, and a brake BO is provided between the sun gear SO and the housing Hu.

For hydraulic control, the input rotation sensor 21 as the detecting means 2 for detecting the rotation speed of the clutch CO as the rotating member 10 is arranged on the outer peripheral side of the clutch CO.

The sun gears S1 and S2 of each planetary gear mechanism of the first transmission portion T are provided on a common sun gear shaft SG, and the left (front side) planetary gear mechanism of the first transmission portion T in the drawing. A first clutch C1 is provided between the first clutch C1 and the sun gear shaft SG.
A second clutch C2 is provided between the ring gear RO of the second transmission portion OD and the ring gear RO.

In the first transmission portion T, the carrier PC1 of the planetary gear mechanism on the left side in the figure and the ring gear Rr on the right side (rear side) in the figure are integrally connected, and the carrier PC1 and the ring gear Rr are connected to each other. The output shaft OS is connected.

A first brake B1 which is a band brake is provided on the outer peripheral side of the clutch drum of the second clutch C2 so as to stop the rotation of the sun gear shaft SG. A second one-way clutch F2 and a third brake B3 are arranged in parallel between the carrier PC2 and the housing Hu in the planetary gear mechanism. As shown in FIGS. 2 and 3, the manual valve 100 is
The line pressure PL is adjusted by a primary regulator valve (not shown).

In the D range, the spool 101 is in the position shown in the figure, and the input port 102 is connected to the D port 10.
3 is connected. In the S range,
The spool 101 moves to the lower side of the figure and the input port 102
Communicates with the D port 103 and the S port.

In the L range, the spool 101 moves further downward to move the input port 102D port 103, S port
In the N range, the spool 101 is connected to the input port 10 and the L port 105.
2 closed, input port 102 is R port 1 in the R range
In the P range, the input port 102 is closed, and the other ports are connected to the drain port.

Shifting between first speed and second speed 1-2
The shift valve 200 includes a spool 201 having four lands as shown in FIG. 3 and a spring 202 disposed at one end thereof. A control port 203 is connected to the second solenoid valve 42, When the two solenoid valve 42 is off, a line pressure PL supplied from the line pressure oil passage 61 via the strainer 62 and the orifice 63 is generated at the control port 203.

Shifting between the second speed and the third speed 2-3
As shown in FIG. 3, the shift valve 300 includes a spool 301 having six lands and a spring 302 disposed at one end thereof. A control port 303 is connected to the first solenoid valve 41, and 1 When the solenoid valve 41 is off, the manual valve 10
The line pressure PL supplied from the zero D port 103 via the strainer 65 and the orifice 66 is generated at the control port 303.

3-4 for shifting between third speed and fourth speed
The shift valve 400 includes a spool 401 having four lands as shown in FIG. 3 and a spring 402 disposed at one end of the spool 401. The control port 403 is the control port of the above-described 1-2 shift valve 200. 20
3, is connected to the second solenoid valve 42,
The hold port 404 is used for the 2-3 shift valve 300.
Is connected to the hold output port 307 of the control circuit.

FIG. 4 shows the first solenoid valve 41 and the second solenoid valve 42 at each of the first to fourth speeds, the clutches C0 to C2, the brakes B0 to B3, and the one-way clutches F1 to F1. The operation state of each friction engagement device of F3 is shown in the table, where the mark ○ indicates ON for the solenoid valve and engagement for the friction engagement device, and the mark X indicates OFF for the solenoid valve and friction. The engagement device indicates release.

The correspondence between the detection signal from the detection means 2 (input rotation sensor 21) and the input state to the shift control solenoids 41 and 42 will be described based on this operation table.

In the first speed, the first solenoid valve 41 is turned on, the second solenoid valve 42 is turned off, and pressure oil is supplied to the clutch C0 along the hydraulic circuit shown in FIG. Therefore, since the clutch C0, which is a friction engagement element as the rotating member 10, rotates, a comparison between the input rotation sensor 21 and the output rotation sensor 22
The failure of the input rotation sensor 21 can be detected.

In the second speed, the first solenoid valve 41,
Both the second solenoid valve 42 is turned on, and pressure oil is supplied to the clutch C0 along the hydraulic circuit shown in FIG.
Therefore, since the clutch C0, which is a frictional engagement element as the rotating member 10, rotates, the failure of the input rotation sensor 21 can be detected as in the case of the first speed.

At the third speed, the first solenoid valve 41 is turned off, the second solenoid valve 42 is turned on, and pressure oil is supplied to the clutch C0 along the hydraulic circuit shown in FIG. Therefore, the clutch C0, which is a frictional engagement element as the rotating member 10, rotates, so that a failure of the input rotation sensor 21 can be detected.

In the fourth speed, the first solenoid valve 41,
Since both the second solenoid valves 42 are turned off, no pressure oil is supplied to the clutch C0, and the clutch C0 as a frictional engagement element as the rotating member 10 does not rotate. Therefore, since there is no input from the input rotation sensor 21, the failure cannot be detected.

Therefore, the first solenoid valve 41 and the second solenoid valve 41
In addition to the fourth speed in which both the solenoid valves 42 are turned off, for example, when the commanded shift speed of the electronic control unit 30 is the first speed, the first solenoid valve 41 fails and the first speed is set.
When the solenoid 41 is turned off, the electronic control unit 3
If the second solenoid 42 is turned off due to the failure of the second solenoid valve 42 when the 0th command gear is in the third speed, the automatic transmission is in the fourth speed state (the first solenoid valve 41 and the second solenoid valve 42). Both are off)
Since the clutch C0 does not rotate, an input from the input rotation sensor 21 cannot be obtained, and the failure cannot be detected.

The storage element (ROM) connected to the central processing element (CPU) of the electronic control unit 30 includes:
A determination program for detecting a failure of the detection means described below is stored in advance.

Referring to FIG. 5, a procedure for detecting a failure of the input rotation sensor 21 as the detection means will be described below with reference to FIG.

In step 101, the detecting means 2
It is checked whether the input rotation sensor 21 satisfies the condition for prohibition of failure detection.

If the condition does not correspond to the condition for prohibiting the failure detection of the detecting means, it is checked in step 102 whether the shift speed is the second speed. If the speed is the second speed, in step 103, the output rotation sensor 22 outputs four pulses. It is checked whether there is an input from the input rotation sensor 21 as the detecting means 2 while there is an input. If there is an input from the input rotation sensor 21, the failure detection counter n is reset (n = 0) in step 104.

If there is no input from the input rotation sensor 21, 1 is added to n in step 105, and it is checked whether or not n is 500 in step 106. If n is less than 500, the program returns to the beginning of the program and 500 Is reached in step 107, the failure is determined and the program is terminated.

In the control device for an automatic transmission according to the first embodiment having the above structure, the monitoring means 5 monitors the input state of the electric signal from the computer 3 to the shift control solenoids 41 and 42, and The judging means 6 detects the detection signal from the input rotation sensor 21 and the monitoring means 5
The shift control solenoids 41 and 42 monitored by
A failure of the input rotation sensor 21 as the detection means 2 is determined based on a correspondence relationship with an input state of an electrical signal to the input rotation sensor 21.

The control device for the automatic transmission according to the first embodiment having the above-described operation is configured to input the detection signal from the detection means 2 and the electric signal to the transmission control solenoids 41 and 42 monitored by the monitoring means 5. The input rotation sensor 2 as the detection means 2 is determined by the correspondence with the state.
Since the failure of the input rotation sensor 21 is determined, the failure of the input rotation sensor 21 as the detection means 2 can be detected accurately and reliably.

Further, in the control device for an automatic transmission according to the first embodiment, the monitoring means 5 may be arranged such that the monitoring means 5 controls the computer 3 in the second gear, in which an electric signal is inputted to the two shift control solenoids 41 and 42. Monitors the input state of the electric signal to the shift control solenoid from the state described above. Therefore, even if one of the solenoids is electrically or mechanically broken, the rotating member 10 as the detected means 1 is constantly rotating. , To determine the failure of the detection means 2,
This has the effect of detecting the failure of the input rotation sensor 21 more reliably.

Further, in the control device for an automatic transmission according to the first embodiment, the judgment means 6 determines whether the electric signal of the electric gear at the gear position where the electric signal is inputted to at least two of the gear change control solenoids 41 and 42 is provided. Since the failure of the detection means 2 is determined based on the input state, the effect of accurately and reliably detecting the failure of the input rotation sensor 21 is achieved.

In the control device for an automatic transmission according to the first embodiment, since the rotating member 10 is a clutch CO as a friction engagement element of the automatic transmission, one of the solenoids is electrically or mechanically operated. Even if a failure occurs, the clutch CO as the friction engagement element of the automatic transmission is constantly rotating, thereby avoiding erroneous detection of a failure of the input rotation sensor 21 caused by stopping the clutch CO. It has the effect of doing.

Further, in the control method of the automatic transmission according to the first embodiment, the input rotation sensor 21 is controlled based on an input state of the electric signal at a shift speed at which an electric signal is input to at least two shift control solenoids 41. Therefore, even if one of the solenoids fails electrically or mechanically, the input rotation sensor 2 can be accurately and reliably avoided by avoiding erroneous detection as in the conventional device.
1 is determined.

In the control method of the automatic transmission according to the first embodiment, the input signal is input to the two shift control solenoids 41 and 42 according to the input state of the electrical signal in the second shift stage. Since the failure of the rotation sensor 21 is determined, the effect of preventing erroneous detection of the failure of the input rotation sensor 21 due to the failure of the solenoid is exerted.

Further, in the control method of the automatic transmission according to the first embodiment, the input rotation sensor 21 as the detection means 2 is used as the rotation member 10 as the detection means 1 and the friction engagement element of the automatic transmission is used. Since the rotation of the (clutch CO) is detected, it is possible to detect a failure of the detection means 2 in a state where the friction engagement element of the automatic transmission is rotating, and the failure is detected. In this case, the electronic control unit 30 can promptly respond to a control change of the automatic transmission A as a fail-safe.

(Second Embodiment) The control device and the control method for an automatic transmission according to the second embodiment detect a failure of the input rotation sensor 21 as detection means described below as shown in FIG. Compared to the first embodiment, the first and second shift control solenoids 41, 42
The difference is that the function of judging the functional failure is added. The difference will be mainly described, and the same portions will be denoted by the same reference numerals and description thereof will be omitted.

The storage element (R) of the electronic control unit 30
Steps 108 to 112 are added after step 106 in the determination program of the failure detection of the input rotation sensor 21 stored in advance in the OM) as a detecting means.

That is, at step 106, it is checked whether or not n is 500 as in the first embodiment.
If it has reached 0, it is checked in step 108 whether or not there is an input from the input rotation sensor 21 when the shift stage is the first speed.

If there is an input from the input rotation sensor 21 when the speed is the first speed, it is checked in step 109 whether there is an input from the input rotation sensor 21 when the speed is the second speed. Is performed.

If there is no input from the input rotation sensor 21 when the shift stage is the second speed, it is determined in step 110 that the input rotation sensor 21 is malfunctioning.

If there is an input from the input rotation sensor when the speed is the second speed, it is determined in step 111 that the second shift control solenoid 42 is malfunctioning.

If there is an input from the input rotation sensor when the gear is the first speed, it is determined in step 112 that the first shift control solenoid 41 is malfunctioning.

The control device and the control method of the automatic transmission according to the second embodiment are similar to those of the first embodiment, except that the shift control solenoid 41, which is detected by the detection means 2 and monitored by the monitoring means 5, Since the failure of the detection means 2 is determined based on the correspondence with the input state of the electric signal to the input signal 42, the effect of accurately and reliably detecting the failure of the input rotation sensor 21 as the detection means 2 is achieved.

Further, the control device and the control method of the automatic transmission according to the second embodiment also enable determination of a functional failure of the first and second transmission control solenoids 41 and 42, thereby enabling comprehensive failure determination. This has the effect.

The above-described embodiments are exemplarily described for explanation, and the present invention is not limited to these embodiments. Those skilled in the art will recognize from the claims, the detailed description of the invention, and the drawings. Modifications and additions are possible without departing from the technical idea of the present invention.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a control device and a control method of an automatic transmission according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing a basic configuration of the first embodiment.

FIG. 3 is a hydraulic circuit diagram showing a part of the hydraulic circuit according to the first embodiment.

FIG. 4 is an explanatory diagram showing an operation state of a solenoid valve according to the first embodiment.

FIG. 5 is a chart showing a procedure for determining a failure of the detection means in the first embodiment.

FIG. 6 is a chart illustrating a procedure for determining a failure of a detection unit and a solenoid according to a second embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Detected means 10 Rotating member 2 Detecting means 3 Computer 41, 42 Shift control solenoid 5 Monitoring means 6 Judgment means

Claims (7)

[Claims] At least two shift control solenoids control a shift, a detecting means detects a rotation of a rotating member as a detected means in an automatic transmission, and an electric signal is input to any of the shift control solenoids. In a method for controlling an automatic transmission in which the rotating member does not rotate at a shift speed that is not performed, at least two shift control solenoids receive an electrical signal at a shift speed. A method for controlling an automatic transmission, comprising determining a failure. 2. The control method for an automatic transmission according to claim 1, wherein a failure of said detection means is determined based on an input state of an electric signal in a second shift speed. 3. The control method for an automatic transmission according to claim 2, wherein the detection unit detects rotation of a friction engagement element of the automatic transmission. 4. A detecting means for detecting rotation of a rotating member as a means to be detected in the automatic transmission, a computer for outputting an electric signal for controlling the automatic transmission based on a detection signal from the detecting means, A control device for an automatic transmission comprising at least two shift control solenoids for controlling a shift based on an electrical signal from a computer, wherein a monitoring means for monitoring an input state of an electrical signal from the computer to the shift control solenoid And determining means for determining a failure of the detecting means based on a correspondence relationship between a detection signal from the detecting means and an input state of an electric signal to the shift control solenoid monitored by the monitoring means. Control device for automatic transmission. 5. The method according to claim 4, wherein the determination unit determines a failure of the detection unit based on an input state of the electric signal at a gear at which an electric signal is input to at least two of the shift control solenoids. A control device for an automatic transmission, comprising: 6. The control device for an automatic transmission according to claim 5, wherein said monitoring means monitors an input state of an electric signal from said computer to said shift control solenoid in a second shift speed. 7. The control device for an automatic transmission according to claim 6, wherein the rotating member is a friction engagement element of the automatic transmission.