Method for determining creeping quiescent current faults

Abstract

Method (400) for determining a quiescent current threshold value (210) for an electrical system of a vehicle (100), the method (400) comprising - Determining (401) a plurality of quiescent current data sets (310) of a corresponding plurality of vehicles (100); wherein a quiescent current data set (310) of a vehicle (100) comprises a quiescent current measured value of the vehicle (100) and a value for one or more vehicle parameters (301) of the vehicle (100); - Determining (402) a plurality of classes (311, 312, 313) by cluster analysis of the plurality of idle current data sets (310); wherein a class (311, 312, 313) comprises a vehicle group (331, 332, 333) described by one or more values for one or more vehicle parameters (301), and a class idle current (321, 323, 333) for the vehicle group (331, 332, 333); and - determining (403) a quiescent current threshold value (210) based on at least one of the class quiescent currents (321, 323, 333) of the plurality of classes (311, 312, 313).

Description

[0001] The invention relates to a method and a corresponding device for detecting a faulty quiescent current behavior of a vehicle.

[0002] Vehicles (especially road and / or motor vehicles, such as passenger cars, trucks, or motorcycles) typically include a battery for storing electrical energy. Electrical energy from the battery powers selected electrical loads (e.g., an anti-theft alarm system or a keyless entry function of the vehicle) even when the vehicle is at rest. Therefore, the battery also provides a so-called quiescent current when the vehicle is at rest.

[0003] An increased quiescent current can cause the battery level to drop so low after a longer or shorter period of inactivity that the vehicle may no longer be able to start. For this reason, it is advantageous to reliably detect a situation in which an abnormally increased quiescent current is present in order to initiate countermeasures at an early stage.

[0004] According to the prior art, a method for determining the open-circuit voltage of a motor vehicle battery is known from document DE 10 2007 031 304 A1, in which the open-circuit voltage is determined in a rest phase of the motor vehicle from battery voltage, battery current and battery temperature values recorded at time intervals.

[0005] DE 10 2007 026 165 A1 deals with a switching device for an on-board power supply system of a motor vehicle for electrically connecting a plurality of consumers of the motor vehicle to at least one electrical energy source, wherein the switching device has at least one electric motor-driven switch.

[0006] DE 103 26 594 A1 relates to a method for testing the quiescent current in a vehicle and to an associated device in which the current measurement is carried out inductively using a measuring device and the measurement data is transmitted wirelessly from the measuring device to a test system for evaluation.

[0007] DE 10 2008 061 304 A1 deals with the transmission of vehicle-relevant data of a vehicle via mobile communication, in which an ignition key radio technology is used in addition to WLAN-based communication in a vehicle to communicate with other vehicles.

[0008] DE 10 2006 043 419 A1 describes a method and a current measuring device for determining a quiescent current of an on-board electrical system of a motor vehicle during vehicle manufacture or vehicle maintenance, wherein the determination of the quiescent current of the on-board electrical system of the motor vehicle during manufacture or maintenance takes place in several steps.

[0009] This document therefore deals with the technical task of reliably detecting the presence of a quiescent current fault.

[0010] The object is achieved by the independent claims. Advantageous embodiments are described, inter alia, in the dependent claims.

[0011] According to one aspect, a method for determining a quiescent current threshold value for an electrical system of a vehicle (e.g., for a road vehicle, such as a passenger car, a truck, or a motorcycle) is described. The quiescent current threshold value can be used to detect a quiescent current fault. The electrical system of a vehicle typically comprises a storage device for electrical energy (e.g., a rechargeable battery). The storage device can provide electrical energy to one or more electrical consumers of the electrical system. The quiescent current of the vehicle typically comprises (or corresponds to) the current required to operate one or more electrical consumers of the vehicle when the vehicle is at rest (in particular, when an engine of the vehicle is switched off and / or when a vehicle is locked).Examples of electrical consumers that cause a quiescent current are an anti-theft alarm system and / or a keyless entry function (also known as “comfort access”) of the vehicle.

[0012] The method comprises determining a plurality of idle current data sets from a corresponding plurality of vehicles. The vehicles are typically different vehicles. The different vehicles may have different properties and / or operating states. The properties and / or operating states of a vehicle can be described using one or more vehicle parameters.

[0013] The quiescent current data set of a vehicle can, in particular, include a quiescent current measured value of the vehicle and at least one value for one or more vehicle parameters. The quiescent current measured value can be detected by a sensor (e.g., a battery sensor) of the vehicle.

[0014] The one or more vehicle parameters of a vehicle can describe one or more properties and / or states of the vehicle. The values for the one or more vehicle parameters can be stored in a memory unit of the vehicle and thus provided together with the quiescent current measured value of the vehicle as a quiescent current data set. For example, the one or more vehicle parameters can include information about one or more of: a manufacturer of the vehicle, a type of vehicle, a series of the vehicle, an equipment of the vehicle (e.g. the presence of a keyless entry function), an ambient temperature of the vehicle (e.g. an average ambient temperature), a humidity in an environment of the vehicle (e.g. an average humidity) and / or a region (e.g. a cold region or a hot region) in which the vehicle is operated.

[0015] This allows a large number of quiescent current data sets to be determined during operation of a large number of vehicles. With a relatively large number of quiescent current data sets and / or a relatively broad differentiation of vehicles, a statistically relevant overview of the quiescent currents of vehicles can be provided.

[0016] The method further comprises determining a plurality of classes by cluster analysis of the plurality of quiescent current data sets. In other words, a classifier can be determined based on the plurality of quiescent current data sets. A cluster algorithm and / or a classification method and / or a machine learning method can be used for this purpose. One class of the plurality of classes comprises a vehicle group that is described by one or more values for one or more vehicle parameters, and a class quiescent current for the vehicle group. Typically, the cluster analysis summarizes measured values into different classes. The vehicle group of a class can be determined from the values of the one or more vehicle parameters of the quiescent current data sets. Furthermore, the class quiescent current of the class (e.g., as the mean value of the quiescent current measured values) can be determined from the quiescent current measured values of the quiescent current data sets.

[0017] When determining the classifier, cluster analysis can consider one or more conditions. In particular, a predefined number of classes can be specified. Alternatively or additionally, a predefined difference between the quiescent currents of different classes (i.e., a predefined distance between the classes) can be specified. This allows the classifier to be adapted to the specific conditions of a set of vehicles under investigation.

[0018] The method further comprises determining a quiescent current threshold based on at least one of the class quiescent currents of the plurality of classes. In particular, the determination may comprise multiplying a class quiescent current by a predefined factor. The predefined factor can be used to adjust the sensitivity of a method for detecting a quiescent current fault.

[0019] The described method enables the precise and differentiated determination of quiescent current thresholds for different vehicles. Based on the quiescent current thresholds determined in this way, the presence of a quiescent current fault in a vehicle's electrical system can be reliably detected.

[0020] According to a further aspect, a method for detecting a quiescent current fault in an electrical system of a first vehicle is described. The method comprises determining one or more first values of one or more vehicle parameters of the first vehicle. Properties and / or states of the first vehicle can be described based on the first values of the one or more vehicle parameters.

[0021] Furthermore, a classifier with a plurality of classes can be provided. The classifier can have been determined using the methods described in this document. A class of the classifier can comprise a vehicle group described by one or more values of one or more vehicle parameters. Furthermore, a class can comprise a class quiescent current for the corresponding vehicle group. The classifier can be configured to assign a respective class quiescent current to a vehicle group. In other words, for a vehicle that falls into a specific vehicle group, the classifier can provide the expected quiescent current of that vehicle (as the class quiescent current of the specific vehicle group).

[0022] The method further comprises determining a first vehicle group of the first vehicle based on the classifier and on the one or more first values of the one or more vehicle parameters of the first vehicle. In particular, the first vehicle can be assigned to a first vehicle group based on the one or more first values of the one or more vehicle parameters. In this case, the vehicle group of the classifier whose values of the one or more vehicle parameters are closest to the first values (possibly on average) can be selected.

[0023] The method also includes determining a first quiescent current threshold for the first vehicle based on the class quiescent current of the first vehicle group. In particular, the class quiescent current of the first vehicle group can be multiplied by a predefined factor.

[0024] The method further includes detecting a quiescent current fault of the first vehicle based on the first quiescent current threshold. For this purpose, a current quiescent current of the first vehicle can be determined. The current quiescent current can then be compared with the first quiescent current threshold. A current quiescent current that reaches or exceeds the first quiescent current threshold can be an indication of the presence of a quiescent current fault.

[0025] As already explained above, determining the quiescent current threshold using a classifier can ensure that quiescent current faults can be reliably detected.

[0026] The method may further include initiating a measure to rectify the quiescent current fault if a quiescent current fault has been detected. Examples of measures include setting an error log entry and / or issuing an error message and / or notifying the vehicle owner and / or the workshop via a telecommunications service.

[0027] According to a further aspect, a control unit for a vehicle is described. The control unit can be configured to carry out a method described in this document. Alternatively or additionally, the control unit can be configured to determine an indicator for a quiescent current of an electrical system of the vehicle (e.g., based on a sensor of the vehicle). The control unit can further be configured to transmit the determined indicator for the quiescent current via a communication unit (in particular via a wireless communication unit) of the vehicle to a unit outside the vehicle. In particular, the indicator for the quiescent current can be provided as a quiescent current data record for determining a classifier. The control unit can thus contribute to providing quiescent current data records from the operation of the vehicle to a central unit for determining the classifier.

[0028] The control unit can further be configured to receive a quiescent current threshold (e.g., via a wireless communication unit of the vehicle). Based on the quiescent current threshold, the presence of a quiescent current fault can then be detected. Thus, quiescent current thresholds can be updated and provided based on an updated classifier, if necessary. This enables improved detection of quiescent current faults.

[0029] According to a further aspect, a vehicle (e.g. a passenger car, a truck or a motorcycle) is described which comprises a control unit described in this document.

[0030] According to another aspect, a software (SW) program is described. The SW program can be configured to be executed on a processor (e.g., on a control unit of a vehicle) and thereby to carry out a method described in this document.

[0031] According to a further aspect, a storage medium is described. The storage medium may comprise a software program configured to be executed on a processor and thereby to carry out a method described in this document.

[0032] It should be noted that the methods, devices, and systems described in this document can be used alone or in combination with other methods, devices, and systems described in this document. Furthermore, any aspects of the methods, devices, and systems described in this document can be combined in a variety of ways. In particular, the features of the claims can be combined in a variety of ways.

[0033] The invention will be described in more detail below with reference to exemplary embodiments. Fig.1 a block diagram of selected components of a vehicle; Fig. 2 shows an example of the quiescent current of a vehicle; Fig. 3 an exemplary cluster analysis of quiescent current data sets; and Fig. 4 a flowchart of an exemplary method for determining a quiescent current threshold.

[0034] As stated at the beginning, this document deals with the detection of an erroneously excessive quiescent current. In this context, Fig. 1 shows a block diagram of exemplary components of a vehicle 100. In particular, Fig.1 a storage device 101 for electrical energy (in particular a rechargeable battery, such as a low-voltage battery, e.g., with an operating voltage of approximately 12V). One terminal of the storage device 101 is typically connected to a ground 102 of the vehicle 100. A current 110 is provided for one or more electrical consumers 104 of the vehicle 100 via another terminal of the storage device 101. When the vehicle 100 is in a standby state, the storage device 101 provides a standby current 110.

[0035] The vehicle 100 further comprises a sensor 103 (e.g., a so-called "intelligent battery sensor, IBS"), which is configured to acquire measurement data regarding a state of the storage device 101. The measurement data may, in particular, include information (e.g., an indicator) regarding the quiescent current 110. In Fig.For this purpose, Figure 1 shows an exemplary connection between battery sensor 103 and the negative terminal of storage device 101. If necessary, sensor 103 can also be connected to the positive terminal of storage device 101 (not shown). Furthermore, the measurement data can include information regarding a temperature of storage device 101 and / or regarding a fill level of storage device 101.

[0036] Furthermore, the vehicle 100 includes a control unit 105 configured to receive and process the measurement data from the sensor 103. In particular, the control unit 105 can be configured to compare the quiescent current indicator 110 with a quiescent current threshold. This comparison can provide an indication that an erroneously elevated quiescent current is present. In particular, an indication of a quiescent current fault can be present if the quiescent current indicator 110 reaches or exceeds the quiescent current threshold.

[0037] Fig.2 shows an exemplary curve of the quiescent current 110 of a vehicle 100 over time 201. The illustrated curve of the quiescent current 110 has current peaks at which the quiescent current 110 exceeds the predefined quiescent current threshold 210. The control unit 105 can be configured to detect intervals 202 in which the quiescent current 110 exceeds the quiescent current threshold 210. Furthermore, the control unit 105 can be configured to determine a cumulative fault current 120 and / or a cumulative fault energy 120. For this purpose, the actual quiescent current 110 in the intervals 202 (or the electrical energy provided in the intervals 202) can be cumulated. A quiescent current fault can be detected when the cumulative quiescent current 120 (or the cumulative energy 120) reaches or exceeds a threshold value 220. By taking the cumulative quiescent current 120 into account, the robustness of the detection of a quiescent current fault can be increased.In particular, it can be avoided that a one-time exceeding of the quiescent current threshold 210 (e.g. due to a punctual effect) leads to the detection of a quiescent current error.

[0038] The control unit 105 may be configured to initiate measures (e.g., the output of an error message) when the cumulative quiescent current 120 reaches or exceeds the threshold value 220, and / or when the quiescent current 110 reaches or exceeds the quiescent current threshold value 210.

[0039] As explained above, exceeding the quiescent current threshold 210 can be interpreted as an indication of the presence of a quiescent current fault. The reliability of this indicator for the presence of a quiescent current fault depends in particular on the level of the quiescent current threshold 210. To avoid false detections, the quiescent current threshold 210 should be above the largest possible quiescent current (including component and / or measurement tolerances) that is possible in vehicles 100 under normal conditions. On the other hand, a high quiescent current threshold 210 means that only significant quiescent current faults can be detected, where the quiescent current 110 exceeds the relatively high quiescent current threshold 210.

[0040] For this reason, gradual quiescent current violations (e.g., a quiescent current of 30 mA instead of the regular 10 mA) are usually not detected at all or only after a prolonged battery discharge. This can lead to battery failures and / or severe discharge with possible pre-damage to memory 101.

[0041] This document describes a method for accurately determining a quiescent current threshold 210 for a vehicle 100.

[0042] This can increase the reliability of detecting a quiescent current fault.

[0043] Fig. 4 shows a flowchart of an exemplary method 400 for determining a quiescent current threshold 210. The method 400 is described with reference to Fig.3. The method 400 comprises determining 401 a plurality of quiescent current data sets 310. The quiescent current data sets 310 can be determined for a plurality of different vehicles 100. The vehicles 100 can be configured to record the respective quiescent currents 110 during operation via the sensor 103. The recorded quiescent currents 110 can then be provided to a central unit (e.g., a server) as quiescent current data sets 310. For example, the quiescent current data set(s) 310 of a vehicle 100 can be transmitted from the vehicle 100 to the central unit via a wireless communication network. Alternatively or additionally, the quiescent current data set(s) 310 can be stored in a memory unit of the vehicle 100. The quiescent current data set(s) 310 can then be read out as needed (e.g., during maintenance of the vehicle 100) and provided to the central unit.

[0044] Determining 401 the plurality of quiescent current data sets 310 may comprise collecting field data from a plurality of vehicles 100. The plurality of quiescent current data sets 310 may thus comprise actually measured quiescent currents 110 (referred to in this document as quiescent current measured values). The quiescent currents 110 may be detected by the sensor 103 during one or more (e.g., all) idle phases of a vehicle 100. The detected quiescent currents 110 may, if necessary, be averaged over time 201 to determine an average quiescent current 110. When the vehicle 100 is started up, the determined quiescent current(s) 110 may be stored in the memory unit and / or transmitted to the central unit.

[0045] A quiescent current measurement value can be associated with one or more vehicle parameters 301. The one or more vehicle parameters 301 of a quiescent current measurement value typically include one or more properties of the vehicle 100 for which the quiescent current measurement value was determined. The one or more vehicle parameters 301 can, for example, include one or more of the following parameters: • a vehicle type (described e.g. by a manufacturer name, a model name, a year of manufacture, a type designation, etc.); • the presence of one or more special equipment on the vehicle 100; and / or • a country / region in which the vehicle 100 is operated. This can particularly affect the ambient temperature, the air humidity, the use of road salt, etc.

[0046] A quiescent current data set 310 of the plurality of quiescent current data sets 310 can thus comprise a vector of data, wherein the vector comprises, as vector components, a quiescent current measured value and values of one or more vehicle parameters 301. The quiescent current measured value represents a measured quiescent current 110 of a vehicle 100, and the values of the one or more vehicle parameters 301 represent properties or states of the vehicle 100 for which the quiescent current measured value was determined.

[0047] The method 400 further comprises determining 402 classes 311, 312, 313 based on the plurality of quiescent current data sets 310. A class 311, 312, 313 comprises quiescent current data sets 310 that include similar quiescent current measured values and similar characteristics (ie, values) of the one or more vehicle parameters 301. The classes 311, 312, 313 can be determined from the plurality of quiescent current data sets 310, for example, using a cluster algorithm and / or a classification analysis (e.g., using a minimal tree method).

[0048] A class 311, 312, 313 can be described in particular by a vehicle group 331, 332, 333, wherein the vehicle group 331, 332, 333 comprises one or more values of the one or more vehicle parameters 301 of vehicles 100 that have similar quiescent currents 110. In other words, a vehicle group 331, 332, 333 describes the properties or states of vehicles 100 that have similar quiescent currents 110. Furthermore, a class 311, 312, 313 includes a class quiescent current 321, 322, 323. The class quiescent current 321, 322, 323 can be determined on the basis of the quiescent current measured values of the quiescent current data sets 310 that fall into the corresponding class 311, 312, 313 (e.g., as the mean value of the quiescent current measured values).

[0049] The method 400 can thus comprise generating 402 a classifier based on the plurality of idle current data sets 310. The classifier is configured to assign a specific vehicle 100 to a vehicle group 331, 332, 333. A vehicle group 331, 332, 333 can be described in particular by a specific characteristic (i.e., by specific values) of one or more vehicle parameters 301. The specific vehicle 100 can be assigned to a specific vehicle group 331, 332, 333 depending on its values for the one or more vehicle parameters 301. A vehicle group 331, 332, 333 is associated with a corresponding class idle current 321, 322, 323 via the class 311, 312, 313. The class quiescent current 321, 322, 323 of the vehicle group 331, 332, 333 to which the specific vehicle 100 is assigned can then be used to determine the quiescent current threshold value 110 for the specific vehicle 100.

[0050] Classes 311, 312, 313 can be determined such that the class quiescent currents 321, 322, 323 have a predefined distance value (a predefined quiescent current difference) from one another. The predefined distance value can be taken into account during cluster formation, i.e., during the formation of classes 311, 312, 313. Furthermore, a number of classes 311, 312, 313 can be specified during cluster formation.

[0051] As explained above, a class 311, 312, 313 is described by a corresponding vehicle group 331, 332, 333. Example vehicle groups 331, 332, 333 are shown in Table 1. As can be seen from Table 1, a vehicle group 331, 332, 333 can include multiple values for a vehicle parameter 301. Furthermore, a vehicle group 331, 332, 333 can apply to all instances of a vehicle parameter 301, if necessary. Table 1 Vehicle group type Special equipment Country / Region 1 small car small amount 2 small car high Compact car 3 off-road vehicle Hot country 4 off-road vehicle Coldland 5 Keyless entry function

[0052] The method 400 may further comprise determining 403 a quiescent current threshold 210 based on the plurality of classes 311, 312, 313, in particular based on the class quiescent currents 321, 322, 323. For example, the quiescent current threshold 210 for a class 311, 312, 313 may be determined by multiplying the corresponding class quiescent current 321, 322, 323 by a safety factor (e.g., by a factor of two).

[0053] The quiescent current threshold values 210 determined in this way can be used in vehicles 100 to detect an indication of the presence of a quiescent current fault. For this purpose, a vehicle 100 can be assigned to a vehicle group 331, 332, 333 using the values of one or more vehicle parameters 301 of the vehicle 100. The corresponding cash register quiescent current 321, 322, 323 then results from the vehicle group 331, 332, 333, from which the quiescent current threshold value 210 for the vehicle 100 can be determined. This quiescent current threshold value 210 can then be stored in a memory unit of the vehicle 100 and used by the control unit 105 to determine an indication of the presence of a quiescent current fault.

[0054] The method 400 makes it possible to precisely determine quiescent current threshold values 210 for different vehicle types. The quiescent current threshold values 210 can be adapted to the actual equipment and / or the actual operating situation of a vehicle 100. Thus, quiescent current errors can be reliably detected. Furthermore, by continuously capturing quiescent current data sets 310, the quiescent current threshold values 210 can be continuously adjusted.

[0055] As already explained above, the control unit 105 can be configured to initiate measures if a quiescent current error has been detected based on the measured quiescent current 110 (e.g., if the quiescent current threshold value 210 is exceeded once or repeatedly). For example, quiescent current errors can already be detected in the factory and suitable countermeasures implemented before the vehicle is delivered to the customer. Alternatively or additionally, continuous monitoring can take place during operation of a vehicle 100. Upon detection of a quiescent current error, an error log entry can be made, a message can be output to a user of the vehicle 100, and / or a message can be sent (e.g., to a maintenance service or the vehicle owner).

[0056] The present invention is not limited to the embodiments shown. In particular, it should be noted that the description and figures are intended only to illustrate the principle of the proposed methods, devices, and systems.

Claims

[1] Method (400) for determining a quiescent current threshold value (210) for an electrical system of a vehicle (100), the method (400) comprising - Determining (401) a plurality of quiescent current data sets (310) of a corresponding plurality of vehicles (100); wherein a quiescent current data set (310) of a vehicle (100) comprises a quiescent current measured value of the vehicle (100) and a value for one or more vehicle parameters (301) of the vehicle (100); - Determining (402) a plurality of classes (311, 312, 313) by cluster analysis of the plurality of idle current data sets (310); wherein a class (311, 312, 313) comprises a vehicle group (331, 332, 333) described by one or more values for one or more vehicle parameters (301), and a class idle current (321, 323, 333) for the vehicle group (331, 332, 333); and - determining (403) a quiescent current threshold value (210) based on at least one of the class quiescent currents (321, 323, 333) of the plurality of classes (311, 312, 313). [2] Method (400) according to claim 1, wherein the one or more vehicle parameters (301) of a vehicle (100) - describe one or more properties of the vehicle (100); and / or - Information about one or more of: a manufacturer of the vehicle (100), a type of the vehicle (100), a series of the vehicle (100), an equipment of the vehicle (100), an ambient temperature of the vehicle (100), a humidity in an environment of the vehicle (100) and / or a region in which the vehicle (100) is operated. [3] Method (400) according to one of the preceding claims, wherein the determining (403) comprises multiplying a class quiescent current (321, 323, 333) by a predefined factor. [4] Method (400) according to one of the preceding claims, wherein the cluster analysis takes into account one or more of the following conditions: - a predefined number of classes (311, 312, 313); and / or - a predefined difference between the class quiescent currents (321, 323, 333) of different classes (311, 312, 313). [5] Method (400) according to one of the preceding claims, wherein the quiescent current (110) of a vehicle (100) comprises the current required for the operation of one or more electrical consumers (104) of the vehicle (100) in a rest state of the vehicle (100). [6] Method for detecting a quiescent current fault of an electrical system of a first vehicle (100), the method comprising - determining one or more first values of one or more vehicle parameters (301) of the first vehicle (100); - Providing a classifier having a plurality of classes (311, 312, 313); wherein a class (311, 312, 313) comprises a vehicle group (331, 332, 333) described by one or more values of one or more vehicle parameters (301), and a class quiescent current (321, 323, 333) for the vehicle group (331, 332, 333); - determining a first vehicle group (331, 332, 333) of the first vehicle (100) on the basis of the classifier and on the basis of the one or more first values of the one or more vehicle parameters (301) of the first vehicle (100); - determining a first quiescent current threshold value (210) for the first vehicle (100) based on the class quiescent current (321, 323, 333) of the first vehicle group (331, 332, 333); and - Detecting a quiescent current fault of the first vehicle (100) based on the first quiescent current threshold value (210). [7] The method of claim 6, wherein detecting a quiescent current fault comprises - determining a current quiescent current (110) of the first vehicle (100); and - Comparing the current quiescent current (110) with the first quiescent current threshold (210). [8] A method according to any one of claims 6 to 7, wherein the method further comprises initiating an action to rectify the quiescent current fault if a quiescent current fault has been detected. [9] Control unit (105) for a vehicle (100), wherein the control unit (105) is arranged - to detect an indicator for a quiescent current (110) of an electrical system of the vehicle (100); and - transmitting the detected quiescent current indicator (110) to a unit outside the vehicle (100) via a wireless communication unit of the vehicle (100). [10] Control unit (105) according to claim 9, wherein the control unit (105) is further configured - to receive a quiescent current threshold (210); and - to detect the presence of a quiescent current fault based on the quiescent current threshold value (210).

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