Fault detection method and system suitable for vehicle body provided with retarder

Abstract

The invention relates to a fault detection method and system suitable for a vehicle body provided with a retarder, and relates to the technical field of vehicle body fault detection. The method comprises the following steps: acquiring and detecting a vehicle body state signal of a vehicle body; vehicle body dynamic signals of a vehicle body are obtained and detected; and accessing a buffer and enabling the retarder to enter a test mode to test the function of the retarder. The fault detection system is composed of a controller, a speed signal detection unit, a signal amplifier and a power supply unit which are connected with one another to work cooperatively. According to the method, the effects of comprehensively detecting the fault of the vehicle body provided with the retarder, effectively positioning the fault position and evaluating the fault condition are achieved.

Description

Technical Field

[0001] The present application relates to the technical field of vehicle fault detection, and in particular to a fault detection method and system applicable to a vehicle body equipped with a retarder. Background Art

[0002] In modern vehicle systems, retarders are an important auxiliary braking device and are widely used in various types of vehicles (such as commercial vehicles, rail transit vehicles, etc.) to reduce the load of the main braking system under long downhill or deceleration conditions and improve driving safety. However, when the vehicle body has faults such as abnormal speed or reduced braking performance during operation, it becomes particularly difficult to quickly locate the source of the fault due to the complex coupling relationship between the retarder and the vehicle body's power system, transmission system and braking system.

[0003] At present, vehicle fault diagnosis mainly relies on traditional mechanical detection or on-board fault code reading, but these methods often fail to distinguish whether the fault is caused by the vehicle itself or the retarder. For example, when the vehicle has insufficient braking force or out-of-control speed, maintenance personnel need to check the vehicle power system and retarder system separately, which is not only time-consuming and labor-intensive, but may also lead to low maintenance efficiency due to misjudgment, and even affect driving safety. Summary of the invention

[0004] In order to improve the efficiency of fault detection, the present application provides a fault detection method applicable to a vehicle body equipped with a retarder.

[0005] On the one hand, the present application provides a fault detection method applicable to a vehicle body equipped with a retarder, which adopts the following technical solution: A fault detection method applicable to a vehicle body equipped with a retarder comprises the following steps: Obtaining a vehicle body status signal of the vehicle body and performing detection; Obtaining the vehicle body dynamic signal and performing detection; The function of the retarder is tested by engaging the buffer and placing the retarder into a test mode.

[0006] By adopting the above technical solution, a comprehensive fault detection can be carried out on a vehicle body equipped with a retarder. By first detecting the vehicle body status signal, it can be preliminarily determined whether the basic state of the vehicle body is normal from aspects such as power supply voltage, brake light function and gear control. Then, the vehicle body dynamic signal can be detected to further analyze the dynamic performance of the vehicle body during operation and to troubleshoot potential fault hazards. Finally, the retarder is put into test mode by using a simulator to test the gear function, which can accurately locate the fault point of the retarder system and ensure the safe and reliable operation of the vehicle body and its retarder system.

[0007] Preferably, obtaining and detecting a vehicle state signal of the vehicle body includes: Obtain the ignition switch signal for verification, and the verification of the ignition switch signal includes detecting the supply voltage and determining whether to allow the retarder to start; Obtain the brake light control signal for detection, and the detection of the brake light control signal includes detecting whether the brake light emits light normally; And obtain the gear control signal for detection, and the detection of the gear control signal includes switching different gears of the vehicle body and detecting the voltage at the corresponding gear port of the controller.

[0008] By adopting the above technical solution, comprehensively detect the vehicle body state signals. Verifying the ignition switch signal can initially judge whether the basic power supply state of the vehicle body is normal from the dimension of the supply voltage. Detecting the brake light control signal can determine whether the brake light function is normal. Detecting the gear control signal can troubleshoot potential problems in gear control, and realize initially judging whether the basic state of the vehicle body is normal from multiple dimensions.

[0009] Preferably, obtaining the vehicle body dynamic signal of the vehicle body and detecting it includes: When the vehicle body is in a stopped state, detect the voltage at the speed signal acquisition end of the controller; When the vehicle body starts and is lifted to a predetermined speed, detect the voltage at the speed signal acquisition end of the controller again.

[0010] By adopting the above technical solution, detecting the vehicle body dynamic signal can detect the voltage at the speed signal acquisition end of the controller respectively when the vehicle body is in a stopped state and when it starts and is lifted to a predetermined speed, analyze the dynamic performance of the vehicle body during operation, troubleshoot potential fault hazards, help accurately locate the fault points of the vehicle body and its retarder system, and ensure safe and reliable operation.

[0011] Preferably, it also includes detecting whether there is a pulse signal on the speed signal line; if the controller detects a pulse signal, it is determined that the speed signal line on the vehicle body is normal, but the signal transmission may be interfered; if the controller does not detect a pulse signal, it is determined that the speed signal line is faulty.

[0012] By adopting the above technical solution, by detecting whether there is a square wave pulse on the speed signal line, it is possible to analyze the dynamic performance of the vehicle body during operation from another dimension.

[0013] Preferably, it also includes detecting whether the vehicle body communication line receives a CAN message after the vehicle body starts. If the CAN message is received, send a normal vehicle body communication function signal; if the CAN message is not received, send a vehicle body communication function abnormal signal.

[0014] By adopting the above technical solution, the detection of the vehicle body communication signal is realized.

[0015] Preferably, connect the buffer and put the retarder into the test mode. Testing the functions of the retarder includes the step of pre-testing the basic functions of the buffer, and the pre-testing of the basic functions of the buffer includes the following: Output a pre-test request signal and a simulated vehicle speed signal to the controller through the simulator. After receiving the pre-test request signal, the controller enters the buffer pre-test process; the controller then outputs start signals to the buffer start indicator light, the brake positive indicator light, and the brake negative indicator light; detect whether the buffer start indicator light, the brake positive indicator light, and the brake negative indicator light are normally lit to detect the functions of the corresponding indicator lights; The controller outputs a shutdown signal to the ABS signal lamp, and detects the function of the ABS signal lamp by detecting whether the ABS signal lamp can be normally extinguished.

[0016] By adopting the above technical solution, pre-testing of the retarder is realized, and multiple indicator lights are detected to eliminate the interference of detection lamp failures on subsequent tests.

[0017] Preferably, connect the buffer and put the retarder into the test mode. Testing the functions of the retarder further includes the step of performing a four-gear automatic test on the buffer, and the step of performing a four-gear automatic test on the buffer includes the following: Output a four-gear automatic test request signal and a simulated vehicle speed signal to the controller through the simulator. After receiving the four-gear automatic test request signal, the controller enters the buffer four-gear automatic test process; the controller sequentially outputs start signals to the first gear, the second gear, the third gear, the fourth gear, the brake positive, and the brake negative, and observes whether the buffer start indicator light, the brake positive indicator light, and the brake negative indicator light are lit; if the above indicator lights are all normally lit, it means that the functions of the buffer start, the brake positive, and the brake negative are all okay; if one or more of the above indicator lights cannot be normally lit, it means that the function corresponding to the indicator light that cannot be lit is problematic; The controller outputs a shutdown signal to the ABS function module. If the ABS signal lamp goes out, it means that the ABS function module is normal; if the ABS signal lamp does not go out, it means that the ABS function module is malfunctioning.

[0018] By adopting the above technical solution, the automatic gear functions of the retarder after entering the test mode can be tested, and at the same time, the status of the ABS function module is judged by outputting a shutdown signal to the ABS signal lamp, which helps to accurately locate the fault points of the retarder system and ensure the safe and reliable operation of the vehicle body and its retarder system.

[0019] Preferably, it further includes testing the communication signal of the retarder and observing whether the gear indicator light is normally lit.

[0020] By adopting the above technical solution, the detection of the communication signal of the buffer is realized.

[0021] On the other hand, a fault detection system applicable to a vehicle body equipped with a retarder provided by the present application adopts the following technical solution: A fault detection system applicable to a vehicle body equipped with a retarder includes a controller, a speed signal detection unit, a signal amplifier, and a power supply unit; the output end of the power supply unit is electrically connected to the power supply ends of the controller, the speed signal detection unit, and the signal amplifier; both the speed signal detection unit and the signal amplifier are signal-connected to the controller; the fault detection system is electrically connected to the vehicle body through a first through-wall plug connector and to the retarder through a second through-wall plug connector.

[0022] By adopting the above technical solution, power can be provided for the fault detection system, the detection and transmission of speed signals and gear control signals can be realized, and the connection with the vehicle body and the retarder can be achieved, so as to comprehensively and accurately detect the faults of the vehicle body equipped with a retarder and its retarder system.

[0023] Preferably, the speed signal detection unit includes a PWM amplifier, an optoelectronic isolation module, and a square wave generator. The input end of the PWM amplifier receives the speed signal, the output end of the PWM amplifier is electrically connected to the speed signal acquisition end of the controller through the optoelectronic isolation module, and the square wave generator is used to input a PWM square wave signal to the PWM amplifier.

[0024] By adopting the above technical solution, after the speed signal is amplified by the PWM amplifier, it is transmitted to the speed signal acquisition end of the controller through the optoelectronic isolation module to avoid signal interference; the square wave generator inputs a PWM square wave signal to the PWM amplifier to facilitate the accurate detection of the speed signal and realize the effective detection of the vehicle body speed signal.

[0025] In summary, the present application includes at least one of the following beneficial technical effects: 1. Through comprehensive detection of various signals of the vehicle body and targeted testing of the retarder in combination with a simulator, accurate fault diagnosis of the vehicle body and its retarder system is realized; 2. It can preliminarily judge whether the basic state of the vehicle body is normal from multiple dimensions such as supply voltage, brake light function, and gear control, and realize the comprehensive evaluation of the overall state of the vehicle; 3. Conduct special tests on the functions of each gear of the retarder, accurately locate the fault points of the retarder system, and solve the problems that the traditional method lacks special detection means and systematic detection procedures for the retarder. Description of the Drawings

[0026] Figure 1It is a schematic flowchart of Embodiment 1 of the present application; Figure 2 It is a principle block diagram of Embodiment 2 of the present application; Figure 3 It is a circuit diagram of the first through-wall docking connector in Embodiment 2 of the present application; Figure 4 It is a circuit diagram of the second through-wall docking connector in Embodiment 2 of the present application; Figure 5 It is a circuit diagram of the power supply unit in Embodiment 2 of the present application; Figure 6 It is a circuit diagram of the speed signal detection unit in Embodiment 2 of the present application; Figure 7 It is a circuit diagram of the signal amplifier in Embodiment 2 of the present application; Figure 8 It is a circuit diagram of a part of the controller in Embodiment 2 of the present application; Figure 9 It is a circuit diagram of another part of the controller in Embodiment 2 of the present application. Detailed implementation manners

[0027] The following further elaborates on the present application in conjunction with the attached Figure 1 - attached Figure 9 to further elaborate on the present application.

[0028] Embodiment 1: The embodiment of the present application discloses a fault detection method applicable to a vehicle body equipped with a retarder.

[0029] Referring to Figure 1 , a fault detection method applicable to a vehicle body equipped with a retarder includes the following steps: S1: Obtain the vehicle body state signal of the vehicle body and perform detection.

[0030] S2: Obtain the vehicle body dynamic signal of the vehicle body and perform detection.

[0031] S3: Connect to the buffer and make the retarder enter the test mode to test the functions of the retarder.

[0032] Specifically, in step S1, obtaining the vehicle body state signal of the vehicle body and performing detection includes the following steps: S11, obtain the ignition switch signal of the vehicle body for verification.

[0033] Turn on the electric door lock, and at this time, the controller receives the real-time power supply voltage value. The vehicle body is usually set with a normal power supply voltage value and a rated power supply voltage value. In this embodiment, the normal power supply voltage value is set to 22V, and the rated power supply voltage value is set to 18V. If the detected real-time power supply voltage value is higher than the normal power supply voltage value, the controller outputs a normal power supply signal at this time, allowing the retarder and the vehicle body system to be started. If the detected real-time power supply voltage value is between the normal power supply voltage value and the rated power supply voltage value, the controller outputs a low voltage signal at this time, restricting the use of the high gear of the retarder and triggering an alarm. If the detected real-time power supply voltage value is less than the rated power supply voltage value, the controller outputs a fault signal at this time, cutting off the retarder and triggering a safe parking process.

[0034] S12. Obtain the brake light control signal for detection.

[0035] The power supply outputs a power supply voltage to the positive brake light control port of the controller. After receiving the power supply voltage, the controller controls the brake light to emit light. If the brake light can emit light normally, it is determined that the brake light is normal; if the brake light cannot emit light normally, it is determined that the brake light control line is grounded.

[0036] S13. Connect the gear power supply terminal, switch the different gears of the vehicle body and detect whether there is an abnormality in the function of the corresponding gear port of the controller.

[0037] The power supply outputs a power supply voltage to the gear power supply port of the controller, and then sequentially toggle multiple gear switches on the vehicle. The multiple gear switches include the first gear, the second gear, the third gear, and the fourth gear. Detect the voltage of the control terminal on the controller for outputting the corresponding gear signal. If the corresponding control terminal is at a high level, it is determined to be normal; if one or more of the control terminals are at a low level, it is determined that there is an abnormality in the gear control line.

[0038] In step S2, obtain the vehicle body dynamic signal of the vehicle body and perform detection, including the following steps: S21: The vehicle body enters the stop state, and detect the voltage value of the controller speed signal acquisition terminal. If the controller speed signal acquisition terminal is at a high level, it is determined that the signal line is short-circuited to the power supply. If the controller speed signal acquisition terminal is at a low level, go to step S22.

[0039] S22: Start the vehicle body, increase the speed of the vehicle body to more than 5kM / h, and then detect the voltage value of the controller speed signal acquisition terminal. If the controller speed signal acquisition terminal is at a high level at this time, it is determined that the speed signal is normal; if the controller speed signal acquisition terminal is still at a low level, go to step S23.

[0040] S23: Detect whether there is a square wave pulse signal on the speed signal line through the controller. If the controller detects a pulse signal, it is determined that the speed signal line is normal, but the signal transmission may be interfered. If the controller does not detect a pulse signal, it is determined that the speed signal line has a fault.

[0041] S24: Start the vehicle engine to make the bus enter the active state. Start the vehicle to detect the communication line and check whether a CAN message is received. If a CAN message is received, send a normal signal for the vehicle body communication function; if a CAN message is not received, send an abnormal signal for the vehicle body communication function.

[0042] In step S3, connect the buffer and make the retarder enter the test mode to test the functions of the retarder, including the following steps: S31: Perform pre-test gears for the basic functions of the buffer, including the following sub-steps: S311: Connect the simulator to the controller signal through a plug. At this time, the retarder enters the test mode and is not linked to the actual vehicle speed. The simulator outputs a pre-test request signal and a simulated vehicle speed signal to the controller. After receiving the pre-test request signal, the controller enters the buffer pre-test process.

[0043] S312: The controller outputs a start signal to the buffer start indicator light, the brake positive indicator light, and the brake negative indicator light. If the buffer start indicator light, the brake positive indicator light, and the brake negative indicator light are all normally powered, it means that the lighting functions of the buffer start indicator light, the brake positive indicator light, and the brake negative indicator light are all okay. If one or more of the buffer start indicator light, the brake positive indicator light, and the brake negative indicator light cannot be normally lit, it means that the lighting function of the corresponding indicator light is problematic.

[0044] S313: The controller outputs a turn-off signal to the ABS signal light. If the ABS signal light goes out, it means that the ABS signal light is normal; if the ABS signal light does not go out, it means that the signal line of the ABS signal light is short-circuited.

[0045] S32: Perform four-gear automatic testing on the buffer, including the following sub-steps: S321: The simulator outputs a four-gear automatic test request signal and a simulated vehicle speed signal to the controller. After receiving the four-gear automatic test request signal, the controller enters the buffer four-gear automatic test process.

[0046] S322: The controller outputs start signals to the first gear, the second gear, the third gear, the fourth gear, the brake positive and the brake negative in turn, and observes whether the buffer start indicator light, the brake positive indicator light and the brake negative indicator light are on. If the above indicator lights are all on normally, it means that there are no problems with the functions of the buffer start, the brake positive and the brake negative. If one or more of the above indicator lights cannot be lit normally, it means that there is a problem with the function corresponding to the indicator light that cannot be lit.

[0047] S323: The controller outputs a shutdown signal to the ABS function module. If the ABS signal light is off, it means that the ABS function module is normal; if the ABS signal light is not off, it means that the ABS function module is abnormal.

[0048] S33: The controller analyzes the retarder communication signal and outputs the analysis result.

[0049] Turn on the test mode, select the corresponding baud rate, and then the controller receives the simulated speed signal and sends the speed message. Then press the first gear button, the second gear button, the third gear button and the fourth gear button in sequence, and observe whether the corresponding gear indicator light, the brake positive indicator light and the brake negative indicator light are lit normally. If they can light up normally, it means that the buffer communication function is normal; if they cannot light up normally, it means that there is a problem with the buffer communication function. And. Since different versions of controllers correspond to different vehicles and have different baud rates, select the corresponding baud rate according to the specific situation.

[0050] Embodiment 1 of the present application is a method for fault detection of a vehicle body with a retarder installed. The implementation principle is as follows: through comprehensive detection of various signals of the vehicle body, targeted testing of the retarder in combination with a simulator, accurate fault diagnosis of the vehicle body and its retarder system is realized. Specifically, the vehicle body state signal is first detected, including electric door lock signal verification, brake light control signal detection and gear function detection, and the basic state of the vehicle body is initially judged to be normal from multiple dimensions such as power supply voltage, brake light function and gear control. Subsequently, the vehicle body dynamic signal is detected, covering the speed signal acquisition terminal voltage detection under the vehicle body stop state and low-speed running state, as well as speed signal pulse detection and vehicle body communication signal detection, and the dynamic performance of the vehicle body during operation is further analyzed to troubleshoot potential faults. Finally, the simulator is connected to the vehicle body controller signal to make the retarder enter the test mode, and the various gear functions of the retarder are specially tested, including the analysis of the indicator light function, ABS signal light state and retarder communication signal, so as to accurately locate the fault point of the retarder system and ensure the safe and reliable operation of the vehicle body and its retarder system.

[0051] Embodiment 2: The embodiment of the present application discloses a fault detection system suitable for a vehicle body equipped with a retarder.

[0052] Reference Figure 2 , a fault detection system applicable to a vehicle body equipped with a retarder includes a controller, a speed signal detection unit, a signal amplifier, and a power supply unit. The output terminal of the power supply unit is electrically connected to the power supply terminals of the controller, the speed signal detection unit, and the signal amplifier, and both the speed signal detection unit and the signal amplifier are signal-connected to the controller. Refer to Figure 3 , the fault detection system realizes electrical connection with the vehicle body through a first through-wall pluggable connector. Refer to Figure 4 , the fault detection system realizes electrical connection with the retarder through a second through-wall pluggable connector.

[0053] Refer to Figure 5 , the power supply unit includes a third through-wall pluggable connector. The 4th pin of the third through-wall pluggable connector is electrically connected to the positive terminal of the battery, the 5th pin of the third through-wall pluggable connector is electrically connected to the negative terminal of the battery, and the connection pin corresponding to the 4th pin in the third through-wall pluggable connector is used to output the power supply DC. The connection pin corresponding to the 5th pin in the third through-wall pluggable connector is grounded. In this embodiment, the output voltage value of the power supply DC is 24V.

[0054] Refer to Figure 6 , the speed signal detection unit includes a PWM amplifier, an opto-isolation module, and a square wave generator. The speed signal is input to the PWM amplifier, and the output terminal of the PWM amplifier is electrically connected to the speed signal acquisition terminal of the controller through the opto-isolation module. The square wave generator is used to output a PWM square wave, and the output terminal of the square wave generator is electrically connected to the PWM receiving terminal of the signal amplifier. The original vehicle speed signal is first input to the PWM amplifier for amplitude adjustment. In this embodiment, the PWM amplifier adopts a rail-to-rail output architecture and can process input signals in a wide range of 0 - 30V. The amplified signal is electrically isolated through the opto-isolation module, effectively blocking the common-mode interference that may be introduced by the vehicle electrical system.

[0055] The speed signal detection unit processes the speed signal through the PWM amplifier and the opto-isolation module in sequence and then transmits it to the controller. At the same time, it outputs a PWM square wave to the signal amplifier through the square wave generator, so that the speed signal can be accurately detected and transmitted to the controller for analysis.

[0056] Refer to Figure 7, the signal amplifier is set as a 24V / PLC signal amplifier, and the four gear control lines of the vehicle body are all connected to the input end of the signal amplifier, and the output end of the signal amplifier is electrically connected to the gear signal receiving end of the controller. The combined logic and effect of the signal amplifier is to receive the signals of the vehicle body gear control lines, convert them and then transmit them to the controller, so that the controller can accurately identify the gear signals. Since the vehicle body gear signals need to be matched with the controller to be correctly processed, the signal amplifier plays a bridging role, ensuring the accurate transmission and processing of the gear signals.

[0057] Refer to Figure 8 and Figure 9 , the controller (GX-3U) can be connected to the buffer simulator and the whole vehicle system to implement the above-mentioned estimation and detection method. In addition, the controller is also electrically connected with an RS485 communication module. The RS485 communication module built in the controller supports the Modbus RTU protocol, and the baud rate can be adjusted adaptively.

[0058] The above are all the preferred embodiments of this application. The protection scope of this application is not limited by this. Therefore, all equivalent changes made according to the structure, shape, and principle of this application shall be covered within the protection scope of this application.

Claims

1. A fault detection method applicable to a vehicle body equipped with a retarder, characterized in that: Including the following steps: Obtain the vehicle body status signal of the vehicle body and perform detection; Obtain the vehicle body dynamic signal of the vehicle body and perform detection; Connect to the buffer and make the retarder enter the test mode to test the function of the retarder, and further include the step of performing a four-gear automatic test on the buffer. The step of performing a four-gear automatic test on the buffer includes the following: Output a four-gear automatic test request signal and a simulated vehicle speed signal to the controller through the simulator. After receiving the four-gear automatic test request signal, the controller enters the four-gear automatic test process of the buffer; the controller sequentially outputs start signals to the first gear, the second gear, the third gear, the fourth gear, brake positive, and brake negative, and observes whether the buffer start indicator light, the brake positive indicator light, and the brake negative indicator light are lit; if the above indicator lights are all lit normally, it indicates that the functions of the buffer start, brake positive, and brake negative are all okay; if one or more of the above indicator lights cannot be lit normally, it indicates that there is a problem with the function corresponding to the unlit indicator light; The controller outputs a shutdown signal to the ABS function module. If the ABS signal light goes out, it indicates that the ABS function module is normal; if the ABS signal light does not go out, it indicates that the ABS function module is malfunctioning.

2. The fault detection method for a vehicle body equipped with a retarder according to claim 1, characterized in that: Obtaining the vehicle body status signal of the vehicle body and performing detection includes: Obtain the ignition switch signal for verification. The ignition switch signal verification includes detecting the power supply voltage and determining whether to allow the retarder to start; Obtain the brake light control signal for detection. The brake light control signal detection includes detecting whether the brake light is emitting light normally; And obtain the gear control signal for detection. The gear control signal detection includes switching different gears of the vehicle body and detecting the voltage of the corresponding gear port of the controller.

3. A fault detection method for a vehicle body equipped with a retarder according to claim 1, characterized in that: Obtaining the vehicle body dynamic signal of the vehicle body and performing detection includes: When the vehicle body is in a stopped state, detect the voltage at the speed signal acquisition end of the controller; When the vehicle body starts and is raised to a predetermined speed, detect the voltage at the speed signal acquisition end of the controller again.

4. A fault detection method for a vehicle body equipped with a retarder according to claim 3, characterized in that: It also includes detecting whether there is a pulse signal on the speed signal line; if the controller detects a pulse signal, it is determined that the speed signal line on the vehicle body is normal, but the signal transmission may be interfered; if the controller does not detect a pulse signal, it is determined that the speed signal line is faulty.

5. The fault detection method for a vehicle body equipped with a retarder according to claim 3, characterized in that: It also includes detecting whether the vehicle body communication line receives a CAN message after the vehicle body starts. If the CAN message is received, a vehicle body communication function normal signal is sent; if the CAN message is not received, a vehicle body communication function abnormal signal is sent.

6. The fault detection method for a vehicle body equipped with a retarder according to claim 1, characterized in that: Connect to the buffer and make the retarder enter the test mode. Testing the function of the retarder includes the step of performing a preliminary test on the basic function of the buffer, and the preliminary test on the basic function of the buffer includes the following: Output a pre-test request signal and a simulated vehicle speed signal to the controller through the simulator. After receiving the pre-test request signal, the controller enters the buffer pre-test process; the controller then outputs start signals to the buffer start indicator light, the brake positive indicator light, and the brake negative indicator light; detect whether the buffer start indicator light, the brake positive indicator light, and the brake negative indicator light are normally lit to detect the functions of the corresponding indicator lights. The controller outputs a turn-off signal to the ABS signal lamp, and detects the function of the ABS signal lamp by detecting whether the ABS signal lamp can be normally turned off.

7. A fault detection method for a vehicle body equipped with a retarder according to claim 6, characterized in that: It also includes testing the retarder communication signal and observing whether the gear position indicator light is normally lit.

8. A fault detection system applicable to a vehicle body equipped with a retarder, applicable to the fault detection method described in any one of claims 1-7, characterized in that: It includes a controller, a speed signal detection unit, a signal amplifier, and a power supply unit; the output end of the power supply unit is electrically connected to the power supply ends of the controller, the speed signal detection unit, and the signal amplifier; both the speed signal detection unit and the signal amplifier are signal-connected to the controller; the fault detection system is electrically connected to the vehicle body through a first through-wall plug connector and is electrically connected to the retarder through a second through-wall plug connector.

9. A fault detection system for a vehicle body equipped with a retarder according to claim 8, characterized in that: The speed signal detection unit includes a PWM amplifier, an opto-isolation module, and a square wave generator. The input end of the PWM amplifier receives the speed signal, the output end of the PWM amplifier is electrically connected to the speed signal acquisition end of the controller through the opto-isolation module, and the square wave generator is used to input a PWM square wave signal to the PWM amplifier.

Images