OBDII wire harness connection detection device and automobile diagnosis equipment

Abstract

The application relates to an OBDII wire harness connection detection device and an automobile diagnosis equipment. The OBDII wire harness connection detection device adopts a data acquisition module to acquire a first data signal of an OBDII wire harness power supply pin and second data signals of each data pin of the OBDII wire harness, then a control module obtains the first data signal and the second data signals, if the voltage of the first data signal reaches a working voltage threshold value, it is indicated that the automobile diagnosis instrument 103 has been connected to an automobile electronic control system, at this time, the control module can determine the connection detection result of the OBDII wire harness according to the signal waveforms of the second data signals, so whether the OBDII wire harness itself has a fault or whether there is a problem of poor contact between the OBDII wire harness and the automobile electronic control system can be known, thereby leading to abnormal connection of the diagnosis instrument and the automobile electronic control system. The connection detection device is simple in structure and convenient for users to carry and use.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of automobile diagnosis, in particular to an OBDII wire harness connection detection device and an automobile diagnosis equipment. BACKGROUND

[0002] In automobile diagnosis, the OBDII (On-Board Diagnostics) interface is used for connection with the automobile. The diagnosis instrument needs to be connected with the automobile through a wire harness. The connection through the wire harness may be poor due to improper insertion during insertion, or the wire harness itself may have a problem, which finally leads to the failure of the diagnosis instrument to normally communicate with the automobile. However, in this case, the user cannot perceive it, which affects the user's use.

[0003] The traditional scheme for measuring the continuity of the wire harness is based on the detection of the factory wire harness by using a specific fixture. It is inconvenient for the user to detect it by himself. SUMMARY

[0004] The present application provides an OBDII wire harness connection detection device which can facilitate the user to detect the continuity of the wire harness

[0005] An OBDII wire harness connection detection device, the device comprises:

[0006] A data acquisition module connected with a target end of an OBDII wire harness connected with the automobile diagnosis instrument, for acquiring a first data signal of a power pin of the OBDII wire harness and a second data signal of a data pin of the OBDII wire harness;

[0007] A control module connected with the data acquisition module, for acquiring the first data signal and the second data signal, and determining a connection detection result of the OBDII wire harness according to a signal waveform of each second data signal if a voltage of the first data signal reaches a working voltage threshold.

[0008] In some embodiments, the control module is further configured to:

[0009] determine a single-wire signal and a differential signal pair in each second data signal according to a voltage of each second data signal, and obtain a bus signal of each single-wire signal and each differential signal pair;

[0010] if a waveform slope of all bus signals is within a preset slope range, it is determined that the OBDII wire harness is normally connected with the automobile electronic control system.

[0011] In some embodiments, the device further comprises:

[0012] A data sending module connected with the target end and the control module, respectively;

[0013] The control module is further configured to:

[0014] If the slope of the waveform of the bus signal is maintained at 0, the control module controls the data sending module to send a pre-stored data signal to the target end, so that the data acquisition module acquires a new second data signal;

[0015] According to the voltage of each new second data signal, the single-wire signal and the differential signal pair are determined, a new bus signal of each single-wire signal and each differential signal pair is obtained, and the connection detection result of the OBDII wire harness is determined according to the signal waveform of each new bus signal.

[0016] In some embodiments, the control module is further configured to determine that the OBDII wire harness is normally connected with the automobile electronic control system if the slope of the waveform of all new bus signals is within the preset slope range.

[0017] In some embodiments, the control module is further configured to determine that the OBDII wire harness is abnormally connected with the automobile electronic control system if the slope of the waveform of a new bus signal is out of the preset slope range.

[0018] In some embodiments, the device further comprises:

[0019] An impedance module connected with the target end, the data acquisition module and the control module respectively;

[0020] The control module is further configured to:

[0021] If the slope of the waveform of the bus signal is out of the preset slope range and is not maintained at 0, the control module controls the impedance module to access the conductive path where the OBDII wire harness and the automobile electronic control system are located.

[0022] After the impedance module is accessed, if the slope of the waveform of all bus signals is within the preset slope range, it is determined that the OBDII wire harness is normally connected with the automobile electronic control system.

[0023] In some embodiments, the control module is further configured to determine that the OBDII wire harness is abnormally connected with the automobile electronic control system if the slope of the waveform of the bus signal is out of the preset slope range after the impedance module is accessed.

[0024] In some embodiments, the device further comprises:

[0025] A grounding module connected with the target end and the control module respectively;

[0026] The control module is further configured to control the grounding module to access the conductive path between the data pin and the automobile electronic control system when the second data signal is not acquired.

[0027] In some embodiments, the device further comprises:

[0028] A display module, connected to the control module, is configured to acquire and display the connection detection result.

[0029] An automobile diagnosis device, comprising:

[0030] An automobile diagnosis instrument;

[0031] and the OBDII harness connection detection device of any one of the above embodiments.

[0032] The OBDII harness connection detection device acquires the first data signal of the OBDII harness power pin and the second data signal of each data pin of the OBDII harness by using the data acquisition module, and then the control module acquires the first data signal and the second data signal. If the voltage of the first data signal reaches the working voltage threshold value, it indicates that the automobile diagnosis instrument has been connected to the automobile electronic control system. At this time, the control module can determine the connection detection result of the OBDII harness according to the signal waveform of each second data signal. In this way, it can be known whether there is a fault in the OBDII harness itself, or there is a problem of poor contact between the OBDII harness and the automobile electronic control system, thereby causing the automobile diagnosis instrument to be abnormally connected to the automobile electronic control system. The connection detection device has a simple structure, and is convenient for users to carry and use. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 A structural block diagram of the OBDII harness connection detection device of an embodiment of the present application;

[0034] Figure 2 A structural block diagram of the OBDII harness connection detection device of another embodiment of the present application;

[0035] Figure 3 A structural block diagram of the OBDII harness connection detection device of another embodiment of the present application;

[0036] Figure 4 A structural block diagram of the OBDII harness connection detection device of another embodiment of the present application;

[0037] Figure 5 A structural block diagram of the OBDII harness connection detection device of another embodiment of the present application;

[0038] Figure 6 A structural block diagram of the OBDII harness connection detection device of another embodiment of the present application. EMBODIMENTS

[0039] It should be understood that the specific embodiments described herein are merely exemplary and do not limit the application.

[0040] The technical solutions in the embodiments of the present application will be clearly and completely described with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative effort fall within the scope of protection of the present application.

[0041] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present application are merely used to explain the relative positional relationship, movement condition, etc. between components in a certain posture (as shown in the drawings), and if the certain posture changes, the directional indications also change accordingly. The connection can be direct connection or indirect connection.

[0042] In addition, the description such as "first", "second" and the like in the present application is only for the purpose of description, and cannot be understood as indicating or implying the relative importance of the indicated technical features or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first", "second" can be explicitly or implicitly included. In addition, the technical solutions of each embodiment can be combined with each other, but it must be based on the realization of a person of ordinary skill in the art, and when the combination of technical solutions is contradictory or cannot be realized, it should be considered that the combination of technical solutions does not exist, and is not within the scope of protection claimed by the present application.

[0043] Figure 1 An embodiment of the OBDII wire harness connection detection device 100 is shown in the structural schematic diagram as shown in the figure. Figure 1 The automobile diagnostic instrument 103 is connected with the automobile electronic control system 101 through the OBDII wire harness 102, so as to read the working data in the automobile electronic control system 101, to perform automobile fault diagnosis. The target end of the OBDII wire harness 102 is the end of the OBDII wire harness 102 connected with the automobile diagnostic instrument 103. The OBDII wire harness connection detection device 100 comprises a data acquisition module 110 and a control module 120. The data acquisition module 110 is connected with the target end of the OBDII wire harness 102 connected with the automobile diagnostic instrument 103, and is used to acquire the first data signal of the power pin of the OBDII wire harness 102 and the second data signal of each data pin of the OBDII wire harness 102. The control module 120 is connected with the data acquisition module 110, and is used to acquire the first data signal and the second data signal. If the voltage of the first data signal reaches the working voltage threshold value, the connection detection result of the OBDII wire harness 102 is determined according to the signal waveforms of the second data signals.

[0044] The OBDII wire harness 102 generally has 16 pins, generally including power supply pins, ground pins and data pins, the working principle and function of each pin being set by the manufacturer when produced. According to the international general OBD pin definition, pin 4 and pin 6 are ground pins, pin 16 is a power supply pin, and the rest are data pins. Among them, pin 4 is used to connect the chassis ground, pin 6 is used to connect the signal ground, and pin 16 is used to connect the constant power supply.

[0045] The working voltage threshold value can be the voltage value of the signal on the power supply pin of the OBDII wire harness 102 when the automobile diagnostic instrument 103 is normally connected to the automobile electronic control system 101, which can be, for example, 3V. By first comparing the voltage of the first data signal and the working voltage threshold value, it can be determined whether the automobile diagnostic instrument 103 is connected to the automobile electronic control system 101 through the OBDII wire harness 102. If the voltage of the first data signal reaches the working voltage threshold value, it indicates that the automobile diagnostic instrument 103 has been connected to the automobile electronic control system 101 through the OBDII wire harness 102, at which point the connection detection result is determined according to the signal waveform of the second data signal. Conversely, if the voltage of the first data signal does not reach the working voltage threshold value, it indicates that the automobile diagnostic instrument 103 is not connected to the automobile electronic control system 101, at which point it is not necessary to determine the connection detection result according to the signal waveform of the second data signal. In this way, by first determining whether the automobile diagnostic instrument 103 is connected to the automobile electronic control system 101, and then determining whether the connection has a fault, the detection efficiency can be improved.

[0046] The connection detection result includes two results of connection normal and connection abnormal. The connection normal indicates that the OBDII harness 102 is connected normally, and the data transmitted by the OBDII harness 102 is valid data. At this time, the connection between the automobile diagnostic instrument 103 and the automobile electronic control system 101 is fault-free. The connection abnormal indicates that the OBDII harness 102 is connected abnormally, and the data transmitted by the OBDII harness 102 is invalid data. At this time, the connection between the automobile diagnostic instrument 103 and the automobile electronic control system 101 is faulty. The fault reason can be at least one of the following: not using the CAN communication protocol, the OBDII harness 102 itself has a fault, and the connection between the OBDII harness 102 and the automobile electronic control system 101 is poor, etc. The connection detection result determined according to the signal waveform can be the connection detection result determined according to the characteristic parameter of the signal waveform. When the connection is abnormal, the signal received by the automobile diagnostic instrument 103 will be different from the signal sent by the automobile electronic control system 101. The characteristic parameter can be determined according to the difference between the normal signal when the connection is normal and the fault signal when the connection is abnormal. In an embodiment, the control module 120 can also directly determine the connection detection result according to the waveform slope of the second data signal. If the waveform slopes of all the second data signals are within the preset slope range, it is determined that the OBDII harness 102 is connected normally, and the automobile diagnostic instrument 103 is connected fault-free with the automobile electronic control system 101. Otherwise, it is determined to be abnormal.

[0047] The OBDII harness connection detection device 100 described above uses the data acquisition module 110 to acquire the first data signal of the power supply pin of the OBDII harness 102 and the second data signal of each data pin of the OBDII harness 102, and then the control module 120 acquires the first data signal and the second data signal. If the voltage of the first data signal reaches the working voltage threshold value, it indicates that the automobile diagnostic instrument 103 has been connected to the automobile electronic control system 101. At this time, the control module 120 can determine the connection detection result of the OBDII harness 102 according to the signal waveform of each second data signal. In this way, it can be known whether there is a fault in the OBDII harness 102 itself or there is a problem of poor contact between the OBDII harness 102 and the automobile electronic control system 101, thereby causing the connection between the automobile diagnostic instrument 103 and the automobile electronic control system 101 to be abnormal. The connection detection device 100 has a simple structure and is convenient for users to carry and use.

[0048] In an embodiment, the control module 120 is also used to determine single-line signals and differential signal pairs in each second data signal according to the voltage of each second data signal, and obtain bus signals of each single-line signal and each differential signal pair. If the waveform slopes of all the bus signals are within the preset slope range, it is determined that the OBDII harness 102 is connected normally.

[0049] The OBDII wire harness 102 can include a single-wire CAN bus, a low-speed fault-tolerant CAN bus, and a high-speed CAN bus. The low-speed fault-tolerant CAN bus and the high-speed CAN bus use differential twisted pairs for transmission. The two data pins of the differential twisted pair can be used as a group. The combination can be: pin 6 and pin 14, pin 3 and pin 11, pin 3 and pin 8, pin 1 and pin 9, pin 12 and pin 13, or pin 2 and pin 10. The differential twisted pair is used to transmit a differential signal pair. The two second data signals in the differential signal pair have equal voltage amplitudes and opposite phases. Therefore, the control signal can determine the differential signal pair in each second data signal according to the voltage of each second data signal, and then perform differential signal processing on the differential signal pair to obtain the bus signal. The single-wire CAN bus transmits a single-wire signal through a single wire. When the second data signal is a single-wire signal, the second data signal can be directly used as the bus signal. In this way, single-wire signals and differential signal pairs are first screened out to obtain their bus signals, respectively. Since only two second data signals in the differential signal pair can be converted into one bus signal, the number of signals that need to be subjected to waveform slope judgment is reduced, thereby improving the efficiency of connection detection and reducing the workload of the control module 120.

[0050] It can be understood that the control module 120 will determine the waveform slope of all bus signals, thereby ensuring that all data pins of the OBDII wire harness 102 are normally connected, and avoiding the situation that the insertion of the OBDII wire harness 102 into the automobile electronic control system 101 results in the normal connection of some channels.

[0051] The waveform slope of the bus signal can be the slope of the falling edge of the bus signal. The waveform of the bus signal collected when the connection is normal is a square wave, and the slope is high. When the connection is abnormal, the waveform of the bus signal collected may be a sawtooth wave, and the slope has a large difference. Therefore, whether the OBDII wire harness 102 is normally connected can be determined according to the slope range in which the waveform slope of the bus signal falls. The preset slope range is the waveform slope of the bus signal transmitted under the normal connection condition.

[0052] In one embodiment, the apparatus further includes a data sending module 130, as shown in Figure 2 The data sending module 130 is connected to the target end and the control module 120, respectively. The control module 120 is further configured to: if the waveform slope of the bus signal is maintained at 0, control the data sending module 130 to send the pre-stored data signal to the target end, so that the data acquisition module 110 collects new second data signals; determine the single-wire signal and the differential signal pair according to the voltage of each new second data signal, obtain new bus signals of each single-wire signal and each differential signal pair, and determine the connection detection result of the OBDII wire harness 102 according to the signal waveform of each new bus signal.

[0053] It can be understood that the control module 120 can analyze the polling of each bus signal, and when the waveform slope of the bus signal is maintained as 0, it indicates that there is no waveform of the bus signal at this time. In order to exclude the case that the automobile electronic control system 101 does not send a signal through the OBDII wire harness 102, the control module 120 can control the data sending module 130 to send a pre-stored data signal to the target end, so that the pre-stored data signal is transmitted on the OBDII wire harness 102. The data acquisition module 110 can acquire a new second data signal and further send it to the control module 120. After the control module 120 obtains the new bus signal according to the new second data signal, the control module 120 can analyze the signal waveform of the new bus signal, and further determine whether the OBDII wire harness 102 is connected normally.

[0054] The determination of the connection detection result according to the signal waveform of the new bus signal can be similar to the first specific embodiment described above, that is, the connection detection result is determined according to the characteristic parameters of the signal waveform.

[0055] By setting the data sending module 130, when the control module 120 determines that there is no waveform of the bus signal, the data sending module 130 sends a pre-set data signal, thereby excluding the case that the data acquisition module 110 does not acquire the waveform of the second data signal due to the automobile electronic control system 101 not sending a signal through the OBDII wire harness 102, and improving the accuracy of the connection detection.

[0056] In one embodiment, the control module 120 is further configured to determine that the OBDII wire harness 102 is connected normally if the slope of the waveform of all new bus signals is within a pre-set slope range.

[0057] The slope of the waveform of the new bus signal can be the slope of the falling edge of the waveform of the new bus signal. If the slope of the waveform of the new bus signal is within a pre-set slope range, it indicates that the bus signal on the OBDII wire harness 102 has no waveform because the automobile electronic control system 101 does not send a signal, and the OBDII wire harness 102 can be determined to be connected normally.

[0058] In one embodiment, the control module 120 is further configured to determine that the OBDII wire harness 102 is connected abnormally if the slope of the waveform of the new bus signal exceeds the pre-set slope range.

[0059] It can be understood that if there is a new bus signal waveform slope outside the preset slope range, it indicates that the bus signal on the OBDII harness 102 does not have a waveform, which is not caused by the automobile electronic control system 101 not sending a signal. At this time, it can be determined that the OBDII harness 102 is connected abnormally. Among them, the control module 120 can poll the waveform slope of each new bus signal to determine that if there is a bus signal waveform slope that exceeds the preset slope range, it is directly determined that the harness is connected abnormally with the automobile electronic control system 101, without the need to continue to determine the remaining bus signals, so as to improve the efficiency of the connection detection.

[0060] In one embodiment, the device further comprises an impedance module 140, as shown in Figure 3 The impedance module 140 is connected with the target end, the data acquisition module 110 and the control module 120 respectively; the control module 120 is further used for: if there is a bus signal waveform slope that exceeds the preset slope range and is not maintained at 0, controlling the impedance module 140 to access the conductive path where the OBDII harness 102 and the automobile electronic control system 101 are located; after the impedance module 140 is accessed, if the waveform slopes of all bus signals are within the preset slope range, it is determined that the OBDII harness 102 is connected normally.

[0061] It can be understood that if there is a bus signal waveform slope that exceeds the preset slope range and is not maintained at 0, it indicates that the bus signal has a waveform, and there is signal transmission on the OBDII harness 102, but the transmitted signal is abnormal. When the automobile electronic control system 101 is built-in in the automobile, it will access the automobile end impedance to ensure the effective transmission of data. When the automobile electronic control system 101 does not access the automobile end impedance, the waveform of the signal on the OBDII harness 102 is no longer a square wave, so the signal will also be abnormal when the automobile end impedance is not accessed. At this time, if the connection detection result is still determined according to the signal waveform, a misjudgment may occur. Therefore, in order to exclude the deviation of the signal transmitted on the OBDII harness 102 due to the non-access of the automobile end impedance, the control module 120 can control the impedance module 140 to access the conductive path where the OBDII harness 102 and the automobile electronic control system 101 are located when it is determined that there is a bus signal waveform slope that exceeds the preset slope range and is not maintained at 0.

[0062] When the impedance module 140 accesses the conductive path where the OBDII harness 102 and the automobile electronic control system 101 are located, the bus signals on the OBDII harness 102 will change. At this time, if the waveform slopes of all bus signals are within the preset slope range, it indicates that the bus signal waveform slope that exceeds the preset slope range is caused by the non-access of the automobile end impedance. When the impedance module 140 accesses the conductive path, the waveform slope falls within the preset slope range, so the control module 120 will determine that the OBDII harness 102 is connected normally in this case.

[0063] In one embodiment, the control module 120 is further configured to determine that the OBDII harness 102 is connected abnormally if the slope of the waveform of the bus signal exceeds the preset slope range after the impedance module 140 is connected to the OBDII harness 102.

[0064] It can be understood that if the slope of the waveform of the bus signal exceeds the preset slope range after the impedance module 140 is connected to the OBDII harness 102 and the conductive path where the automobile control system 101 is located, it indicates that the slope of the waveform of the bus signal exceeds the preset slope range due to the impedance at the automobile end, and thus the control module 120 determines that the OBDII harness 102 is connected abnormally in this case.

[0065] In one embodiment, the connection detection device 100 further comprises a grounding module 150, as shown in Figure 4 The grounding module 150 is connected to each data pin and the control module 120, respectively; and the control module 120 is further configured to control the grounding module 150 to connect the data pin to the conductive path where the automobile control system 101 is located in the absence of the second data signal.

[0066] The grounding module 150 is configured to connect to the ground. It can be understood that the automobile diagnostic instrument 103 has a driving voltage to maintain its operation, and the driving voltage is usually 2.5V. In order to avoid the interference of the driving voltage on the voltage on the OBDII harness 102, so that it cannot be determined whether the signal collected by the data collection module 110 is the signal of the automobile diagnostic instrument 103 or the signal at the automobile end, the data pin can be connected to the weak pull-down ground, so as to remove the interference of the automobile diagnostic instrument 103, so that the data pin enters a stable state, and when the data collection module 110 starts to collect the second data signal, the control module 120 needs to disconnect the data pin from the ground.

[0067] In one embodiment, the device further comprises a display module 160, as shown in Figure 5 The display module 160 is connected to the control module 120 and is configured to acquire and display the connection detection result.

[0068] The display module 160 can include an LCD lamp or an LED lamp, and can represent different connection detection results by emitting different light signals.

[0069] The embodiment of the present application further provides a connection detection device 100, as shown in Figure 6As shown, it comprises a data acquisition module 110, a control module 120, a data sending module 130, an impedance module 140, a grounding module 150 and a display module 160. The first end of the data acquisition module 110, the first end of the data sending module 130, the first end of the impedance module 140 and the first end of the grounding module 150 are connected with the target end of the OBDII wire harness 102 respectively, the target end of the OBDII wire harness 102 being the end of the OBDII wire harness 102 connected with the automobile diagnostic instrument 103, the second end of the data acquisition module 110, the second end of the data sending module 130, the second end of the impedance module 140 and the second end of the grounding module 150 are connected with the control module 120 respectively, and the control module 120 is further connected with the display module 160.

[0070] The data acquisition module 110 is used to acquire the first data signal of the power pin of the OBDII wire harness 102 and the second data signal of the data pin of the OBDII wire harness 102; the control module 120 is used to acquire the first data signal and the second data signal, if the voltage of the first data signal reaches the working voltage threshold value, then determine the single-wire signal and the differential signal pair in each second data signal according to the voltage of each second data signal, to obtain the bus signal of each single-wire signal and each differential signal pair; if the waveform slope of all bus signals is within the preset slope range, then determine that the OBDII wire harness 102 is connected normally.

[0071] The control module 120 is further used to control the impedance module 140 to access the conductive path where the OBDII wire harness 102 and the automobile electronic control system 101 are located, if the waveform slope of the bus signal exceeds the preset slope range and is not maintained as 0; after the impedance module 140 is accessed, if the waveform slope of all bus signals is within the preset slope range, then determine that the OBDII wire harness 102 is connected normally; after the impedance module 140 is accessed, if the waveform slope of the bus signal exceeds the preset slope range, then determine that the OBDII wire harness 102 is connected abnormally.

[0072] The control module 120 is further used to control the data sending module 130 to send the pre-stored data signal to the target end, if the waveform slope of the bus signal is maintained as 0, so that the data acquisition module 110 acquires the new second data signal; determine the single-wire signal and the differential signal pair according to the voltage of each new second data signal, to obtain the new bus signal of each single-wire signal and each differential signal pair, if the waveform slope of all new bus signals is within the preset slope range, then determine that the OBDII wire harness 102 is connected normally; if the waveform slope of the new bus signal exceeds the preset slope range, then determine that the OBDII wire harness 102 is connected abnormally.

[0073] The control module 120 is further used to control the grounding module 150 to access the conductive path where the data pin and the automobile electronic control system 101 are located, if the second data signal is not acquired.

[0074] The display module 160 is configured to acquire and display the connection detection result.

[0075] The working principle and beneficial effects of the OBDII wire harness connection detection device 100 embodiment can refer to the working principle and beneficial effects of the OBDII wire harness connection detection device 100 described above, and will not be repeated here.

[0076] The application further provides an automobile diagnosis device, which comprises the automobile diagnosis instrument 103 and the OBDII wire harness connection detection device 100 of any one of the above embodiments.

[0077] The automobile diagnosis device not only meets the automobile diagnosis function, but also extends the wire harness detection function, has the wire harness fault detection capability in the automobile diagnosis scene, and improves the practicability of the device.

[0078] The above is only the preferred embodiment of the application, and does not limit the patent scope of the application. Any equivalent structure or equivalent process transformation using the content of the specification and drawings, or direct or indirect application in other related technical fields, is also included in the patent protection scope of the application.

Claims

1. An OBD II harness connection detection device, characterized by, The device comprises: a data acquisition module connected to a target end of an OBDII wire harness connected to an automobile diagnostic instrument, for acquiring a first data signal of a power pin of the OBDII wire harness and a second data signal of a data pin of the OBDII wire harness; a control module connected to the data acquisition module, for acquiring the first data signal and the second data signal, determining single-wire signals and differential signal pairs in each second data signal according to voltages of the second data signals if a voltage of the first data signal reaches a working voltage threshold, obtaining bus signals of each single-wire signal and each differential signal pair, and determining that the OBDII wire harness is connected normally if waveforms of all the bus signals are within a preset slope range; an impedance module connected to the target end, the data acquisition module and the control module respectively; the control module is further configured to control the impedance module to access a conductive path of the OBDII wire harness and an automobile electronic control system if a waveform slope of the bus signal exceeds the preset slope range and is not maintained at 0, and determine that the OBDII wire harness is connected normally if the waveform slopes of all the bus signals are within the preset slope range after the impedance module is accessed.

2. The OBD II harness connection detection device of claim 1, wherein, The OBDII wire harness comprises single-wire CAN bus, low-speed fault-tolerant CAN bus and high-speed CAN bus.

3. The OBD II harness connection detection device of claim 1, wherein, The device further comprises: a data sending module connected to the target end and the control module respectively; the control module is further configured to: control the data sending module to send pre-stored data signals to the target end if the waveform slope of the bus signal is maintained at 0, so that the data acquisition module acquires new second data signals; determine the single-wire signals and the differential signal pairs according to voltages of the new second data signals, obtain new bus signals of each single-wire signal and each differential signal pair, and determine a connection detection result of the OBDII wire harness according to signal waveforms of the new bus signals.

4. The OBD II harness connection detection device of claim 3, wherein, the control module is further configured to determine that the OBDII wire harness is connected normally if the waveform slopes of all the new bus signals are within the preset slope range.

5. The OBD II harness connection detection device of claim 4, wherein, the control module is further configured to determine that the OBDII wire harness is connected abnormally if the waveform slope of the new bus signal exceeds the preset slope range.

6. The OBD II harness connection detection device of claim 1, wherein, the control module is further configured to determine that the OBDII wire harness is connected abnormally if the waveform slope of the bus signal exceeds the preset slope range after the impedance module is accessed.

7. The OBD II harness connection detection device of claim 1, wherein, The device further comprises: a grounding module connected to the target end and the control module respectively; the control module is further configured to control the grounding module to access a conductive path of the data pin and an automobile electronic control system if the second data signal is not acquired.

8. The OBD II harness connection detection device of claim 1, wherein, The device further comprises: a display module connected to the control module, for acquiring and displaying the connection detection result.

9. The OBD II harness connection detection device of claim 8, wherein, The display module comprises an LCD lamp or an LED lamp; the display module is further used for representing different connection detection results by emitting different light signal information through the LCD lamp or the LED lamp.

10. An automobile diagnosis device characterized by comprising: Comprise: An automobile diagnostic instrument; And the OBDII wire harness connection detection device of any one of claims 1 to 9.

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