奔驰C200轿车CAN网络故障一例

2024年1月23日发(作者：昂科拉gx汽车之家)

奔驰C200轿车CAN网络故障一例

2007-08-28 14:43 网友评论数 0 条 进入论坛 关键字:维修 奔驰 点火 尾灯

车身网络

为了克服汽车线束增多而带来的线束布置及可靠性的问题，人们开发了车载网络。随着车载网络在汽车上的普遍应用，汽车上的电子技术又跨上更高的台阶，但同时也给维修人员制造出了很多稀奇古怪的故障。有的故障使车辆众多系统“群死群伤”，有的故障使系统出现了不可思议的故障。下面笔者就结合一例车身网络故障与广大维修人员共同探讨。

一辆奔驰W203C200轿车，用户报修该车在打开点火开关时后尾灯常亮。

根据用户反映的情况，笔者用STAR诊断仪对该车的后SAM进行了诊断，结果设备显示“!”，表示该系统不能与诊断仪进行正常通讯。既然诊断仪已经不能诊断该系统，那么此时就只能根据以往的维修经验进行诊断维修。

这里要注意，奔驰W203轿车出现诊断仪不能与被诊断系统通讯的情况时，并不代表该系统彻底损坏。考虑到该车的后尾灯是由后SAM控制，笔者首先检查了后SAM的外围线路和执行控制元件，但均未发现异常。然而就在笔者检修故障的过程中，突然发现转向灯、雨刮器及危险警告灯全部失灵，同时仪表多功能显示器上也显示“显示器错误”的现象。怎么会出现这样的问题呢,这让笔者有点难以理解，因为该车的雨刮器及前转向灯都是由前SAM控制，难道前SAM也出了问题,为了确认该车的前SAM是否存在故障，笔者用STAR诊断仪对前SAM所控制元件进行了执行诊断操作，结果系统各执行元件都能按诊断仪的命令动作。另外，前SAM的故障储存器储存的故障码为“后SAM通讯中断”。

通过以上所做的元件执行功能操作的结果来看，该车前SAM的工作是完全正常的。既然前SAM可以识别STAR诊断仪所发出的各种命令，说明前SAM网络驱动器

识别电路及CPU能工作正常，同时也可以证明CPU输出指令及功率回路也是正常的。可为什么后SAM的故障会引起前SAM及仪表系统工作混乱呢,

后来笔者仔细分析了该车的网络结构特点，原来奔驰W203C200轿车的车身网络在设计时采用了差动传输方式。系统有CAN-H(高位)和CAN-L(低位)数据线，为了保证整个网络系统的安全性及可靠性，2条线在工作时的电位是相反的，如果一条数据线的电位是5V，那么另一条数据线的电位就为0V，这样两条线上的电压和是不变的。CAN-H和CAN-L是绞绕在一起的，这样可以使CAN总线对电磁干扰不敏感。因为同样的干扰在2条线上产生的影响相同，它们便会互相抵消，这样就使得网络传输的稳定性较高。另外，在差动式网络的两端设有终端电阻，它的作用是避免数据传输终了时反射回来，产生反射波破坏数据传输。一般网络覆盖系统受到干扰后会造成数据误用，干扰严重时还能导致整个系统功能异常。

由于奔驰W203轿车的车身网络在设计时把网络的2个终端分别安装在了前SAM和后SAM内部，即网络的2个终端电阻安装在这2块模块内部。如果后SAM损坏的故障点在终端电阻的电路上，便会导致终端电阻与网络产生断路，这样就会使整个车身网络的电磁兼容性变差，从而出现干扰、数据误用和功能异常等现象。

Vertically split casing pump body should not be removable and

washable. 3.8.1.4 pumps shall conform to the technical level of vertical

and horizontal documents. If there is no provision, in General, the

following requirements: the overall installation of pumps, axial

horizontal deviation of not more than 0.1/1000 horizontal deviation is

less than 0.2/1000; level the measurement flange should be on a level

surface or on the horizontal surface of the pump body. Disintegration of

the installation of the pump, the level of vertical and horizontal

deviation shall be no greater than 0.05/1000; level of horizontal split

casing, the exposed part of the shaft or base on a level work surface.

3.8.1.5 alignment, the following requirements of the pump: pump and

driven half coupling of radial displacement of the machine-side

clearance, axis tilt shall comply with the technical file requirements.

When provided, must meet the following requirements: ... Coupling

diameter d (mm) radial displacement mm two-axis tilt 0.5/10007~9 of

steam turbine-driven pumps and transport high temperature liquid pumps,

State at room temperature when aligning should be reserved in accordance

with design compensation when its temperature changes. 3.8.1.6 bearing

Assembly check that the pump bearing (thick tile), Watts and Watts

should fit tightly on the back, the interference values such as device

files should be provided as 0.02~0.04mm, bearing and axle journal and

the top layer and the shell should be good, without hierarchy, as it

emerges, the alloy surface and surface layer and surface should be

smooth, free of cracks, pores, skin, slag and scratches, and other

defects. Bearing and journal of exposure should be good, contacts within

the contact should be uniform, no square centimeter 2~4 a point, contact

point shall conform to the technical documents of, such as technical

documentation not required, you should comply with the following

requirements: when diluted oil lubrication, the tile on contact angle of

130 ?, contact

笔者按照这个分析思路，首先拔下了后SAM线束插头，然后用万用表测量了数据总线的2个插针间的电阻(终端电阻)，测试结果为无穷大。接着笔者又测量了数

据总线另一个终端电阻，它的电阻值为122Ω。至此，完全可以证明该车出现的一系列故障就是因网络终端断路引起的。在更换后,,,后，试车一切正常。

帕萨特领驭1.8T不能起动故障案例

来源: 财库股票网 日期:2010年10月09日 作者:admins

【推广商讯】 头条:明日3只黑马遭曝光 50万股民共同的选择见证免费试用:股优金融分析系统

财库股票网()是股票原创资讯聚合第一门户,为广大股民提供最权威、及时的原创股票资讯。 文章导读:进入集成在仪表内的网关控制单元J533查询故障码为:01314——发动机控制单元无通信，当前存在;01315——变速器控制单元无通信，偶发。查阅BGC发动机电路图，找到发动机控制单元线束侧插

、T121/60，和组合仪表控制单元线束侧插接器中的T32b/20、T32b/19，分别为动力系统接器中的T121/58

数据总线CAN-L和CAN-H的连接端子。

帕萨特 车型:帕萨特1.8T领驭

相关阅读:公共帕萨特热车欠好着车 用换碳罐吗帕萨特K线故障诊断案例帕萨特汽车维涵养护的题目

问题及解决体例

行驶里程:2025km

故障现象:

Vertically split casing pump body should not be removable and

washable. 3.8.1.4 pumps shall conform to the technical level of vertical

and horizontal documents. If there is no provision, in General, the

following requirements: the overall installation of pumps, axial

horizontal deviation of not more than 0.1/1000 horizontal deviation is

less than 0.2/1000; level the measurement flange should be on a level

surface or on the horizontal surface of the pump body. Disintegration of

the installation of the pump, the level of vertical and horizontal

deviation shall be no greater than 0.05/1000; level of horizontal split

casing, the exposed part of the shaft or base on a level work surface.

3.8.1.5 alignment, the following requirements of the pump: pump and

driven half coupling of radial displacement of the machine-side

clearance, axis tilt shall comply with the technical file requirements.

When provided, must meet the following requirements: ... Coupling

diameter d (mm) radial displacement mm two-axis tilt 0.5/10007~9 of

steam turbine-driven pumps and transport high temperature liquid pumps,

State at room temperature when aligning should be reserved in accordance

with design compensation when its temperature changes. 3.8.1.6 bearing

Assembly check that the pump bearing (thick tile), Watts and Watts

should fit tightly on the back, the interference values such as device

files should be provided as 0.02~0.04mm, bearing and axle journal and

the top layer and the shell should be good, without hierarchy, as it

emerges, the alloy surface and surface layer and surface should be

smooth, free of cracks, pores, skin, slag and scratches, and other

defects. Bearing and journal of exposure should be good, contacts within

the contact should be uniform, no square centimeter 2~4 a point, contact

point shall conform to the technical documents of, such as technical

documentation not required, you should comply with the following

requirements: when diluted oil lubrication, the tile on contact angle of

130 ?, contact

一辆2007年出产的上海公共帕萨特1.8T领驭自动挡轿车，搭载BGC策念头和01V手自一体5挡变速器，行驶里程2025km。车主打救援电话反映，该车在行驶中遇红灯泊车时策念头突然熄火，多次起动不能着车。救援人员赶到现场进行初步检查，在焚烧开关ON状况下，仪表板上除EPC灯和制动踏板指示灯不亮外，其他信息显示均无异常。考试考试起动策念头，策念头可以起动，但运转了约1s后，随即熄灭。再次考试考试起动，故障依旧，总体感受与策念头防盗锁止的现象近似，但防盗指示灯K117并未亮起或呈现闪

灼，于是将车拖进维修站做进一步检查。

故障分析:

毗连VAS5052故障诊断仪，进进策念头节制单元J220查询故障存储器，屏幕显示识别到1个故障码:18056——传动系统数据总线故障。而且该故障码无法断根，属非偶发故障。选择数据块功能选项，读出策念头节制单元与动力系统数据总线其他节制单元间通信的测量值，125显示组为:变速器0，组合仪表0;

126显示组为:平安气 囊0，声名J220与变速器和平安气 囊节制单元通信全数间断。

帕萨特领驭1.8T自动挡轿车动力系统CAN数据总线上的设备有策念头节制单元J220、自动变速器节制单元J217、组合仪表节制单元J285、ABS节制单元J104和平安气 囊节制单元J234，此时有需要利用VAS5052故障诊断仪进进网关节制单元J533，用网关的视角来检验整个动力系统CAN数据总线的通信状况，以确定数据总线上策念头节制单元不能通信的故障性质，即确定故障原因是数据总线受到了干扰，仍

是数据总线链路短路或局部发生了断路。AB汽车网

进进集成在仪表内的网关节制单元J533查询故障码为:01314——策念头节制单元无通信，当前存在;01315——变速器节制单元无通信，偶发。执行断根故障码的独霸，01314不能被删除。选择数据块功能选项，读取125显示组的测量值为:策念头0，变速器1;126组的测量值为:平安气 囊1。上述检查声名，网关与动力系统除策念头以外的其他节制单元通信正常，故障性质属于策念头节制单元与动力系统数

据总线之间局部断路。

从策念头可以起动运行1s的现象分析，策念头节制单元电源供给应该没有题目问题，VAS5052可以访谒策念头节制单元也可证实供电正常，由此判定策念头节制单元J220不能通信的原因有二:一是策念头节制单元与数据总线相连的外部线路间断，二是策念头节制单元J220内的CAN数据总线收发器部门损坏呈现了断路。按照上述分析可知，下一步只要检查动力系统CAN数据总线外部线路的状况就能确定故障原因。

查阅BGC策念头电路图，找到策念头节制单元线束侧插接器中的T121/58、T121/60，和组合仪表节制单元线束侧插接器中的T32b/20、T32b/19，分袂为动力系统数据总线CAN-L和CAN-H的毗连端子。拆开策念头节制单元的插接器和组合仪表节制单元的绿色插接器，测量J220插接器线束侧和J285插接器线束侧对应端子

的导通性。测量功效剖明，J220的T121/58端子和J285的T32b/20端子间的电阻为0.2Ω，J220的T121/60端子和J285的T32b/19端子间的电阻为0.5Ω，这声名J220与J285间的外部数据总线链路未Vertically split casing pump body

should not be removable and washable. 3.8.1.4 pumps shall conform to the

technical level of vertical and horizontal documents. If there is no

provision, in General, the following requirements: the overall

installation of pumps, axial horizontal deviation of not more than

0.1/1000 horizontal deviation is less than 0.2/1000; level the

measurement flange should be on a level surface or on the horizontal

surface of the pump body. Disintegration of the installation of the pump,

the level of vertical and horizontal deviation shall be no greater than

0.05/1000; level of horizontal split casing, the exposed part of the

shaft or base on a level work surface. 3.8.1.5 alignment, the following

requirements of the pump: pump and driven half coupling of radial

displacement of the machine-side clearance, axis tilt shall comply with

the technical file requirements. When provided, must meet the following

requirements: ... Coupling diameter d (mm) radial displacement mm two-axis tilt 0.5/10007~9 of steam turbine-driven pumps and transport high

temperature liquid pumps, State at room temperature when aligning should

be reserved in accordance with design compensation when its temperature

changes. 3.8.1.6 bearing Assembly check that the pump bearing (thick

tile), Watts and Watts should fit tightly on the back, the interference

values such as device files should be provided as 0.02~0.04mm, bearing

and axle journal and the top layer and the shell should be good, without

hierarchy, as it emerges, the alloy surface and surface layer and

surface should be smooth, free of cracks, pores, skin, slag and

scratches, and other defects. Bearing and journal of exposure should be

good, contacts within the contact should be uniform, no square

centimeter 2~4 a point, contact point shall conform to the technical

documents of, such as technical documentation not required, you should

comply with the following requirements: when diluted oil lubrication,

the tile on contact angle of 130 ?, contact

断路。按照上述检查得出结论，既然数据总线外部线路正常，故障原因就可以确定为策念头节制单元内的

数据总线收发器出了题目问题。

故障解除:

改换新的策念头节制单元，将焚烧开关置于ON的位置，仪表上EPC灯和制动踏板指示灯点亮。毗连VAS5052故障诊断仪再次进进网关J533，查阅数据块125显示组的测量值，显示为:策念头1，变速器1。这剖明，策念头节制单元与数据总线通信恢复正常。断根各节制单元内存储的故障码，用密码读取仪读出该车的4位防盗密码，进进指导性功能选项完成对J220的编码及J220与J285间的防盗匹配，对节气 门节制单元J338进行根基设定。完成这一系列独霸，起动策念头，策念头顺遂起动运转，路试确认策念头

在各工况下工作正常，故障彻底解除。

通过故障分析深入探讨舒适系统的信号

传递

故障, 信号, 舒适, 系统, 探讨

车型:polo1.6 两前门电动摇机，两后门手摇机

故障现象:左前门摇机开关控制其自身及右前摇机均无动作

右前门控制其自身也无动作

结论:1)修复舒适总线

2)更换左前门控制单元

3)更换舒适中央模块

故障排除时间:2009年元月4日

故障排除过程及其分析:

1)使用VAS5051进入19网关-08-130数据组，显示如下:

单线 中央1 左前门0 右前门1

数据组1区表明，舒适总线物理层处于单线联系状态中，经检查，左前门铰接处防水组件损坏，雨水严重侵蚀组合插头导致总线的腐蚀，修复断路部分后，1区显示双线，表

明总线物理层恢复正常，但摇机仍无动作。

2)对左前门线路进行了系统的检查，包括2个部分:

1}控制单元的主火线及主搭铁，线路正常。

2}进入46-08-001及002数据组检查分析各开关状态，显示各开关均无异常。

线路检查及分析表明，总线已修复，各线路也无异常，从130组3区显示0可以得出结论，左前门与舒适总线间并无数据传输，尽管总线物理层经修复是正常的，事实上左前门开关的照明也是通过总线传递信号的，但打开小灯后，开关照明并没有点亮，也正好说

明了这一点。

Vertically split casing pump body should not be removable and

washable. 3.8.1.4 pumps shall conform to the technical level of vertical

and horizontal documents. If there is no provision, in General, the

following requirements: the overall installation of pumps, axial

horizontal deviation of not more than 0.1/1000 horizontal deviation is

less than 0.2/1000; level the measurement flange should be on a level

surface or on the horizontal surface of the pump body. Disintegration of

the installation of the pump, the level of vertical and horizontal

deviation shall be no greater than 0.05/1000; level of horizontal split

casing, the exposed part of the shaft or base on a level work surface.

3.8.1.5 alignment, the following requirements of the pump: pump and

driven half coupling of radial displacement of the machine-side

clearance, axis tilt shall comply with the technical file requirements.

When provided, must meet the following requirements: ... Coupling

diameter d (mm) radial displacement mm two-axis tilt 0.5/10007~9 of

steam turbine-driven pumps and transport high temperature liquid pumps,

State at room temperature when aligning should be reserved in accordance

with design compensation when its temperature changes. 3.8.1.6 bearing

Assembly check that the pump bearing (thick tile), Watts and Watts

should fit tightly on the back, the interference values such as device

files should be provided as 0.02~0.04mm, bearing and axle journal and

the top layer and the shell should be good, without hierarchy, as it

emerges, the alloy surface and surface layer and surface should be

smooth, free of cracks, pores, skin, slag and scratches, and other

defects. Bearing and journal of exposure should be good, contacts within

the contact should be uniform, no square centimeter 2~4 a point, contact

point shall conform to the technical documents of, such as technical

documentation not required, you should comply with the following

requirements: when diluted oil lubrication, the tile on contact angle of

130 ?, contact

3)由此可以认为左前门模块已经损坏，更换左前门模块，3区显示为1，表明判断正确，

并且系统可以进行正常的数据收发，但摇机仍然无动作

4)这里出现了一个需要考虑的问题，在总线的物理层和数据链路层都没有问题的情况下，为什么仍然不传递信号呢,按照我们一般的理解，左前门和右前门如果控制其自身工作没有必要使用总线传递信号，但为什么仍然不能工作呢,这说明信号的传输通过了一个

中间模块的中转，它一定是舒适中央模块，更换舒适中央模块，故障立即排除。

5)应该非常深刻地认识到舒适中央模块的这个“中央”地位，从这个案例可以明确信号的传递过程，在舒适中央损坏的情况下，任何门的开关都无法控制其自身，同时各个门彼此都不会再有联系，任何一个开关发出的指令都必须先传递到舒适中央，再由舒适中央对信号进行分析和比较，认可的信号将返回到原来的模块，或传递到其他的模块，模块通过总线接收到这个信号后，会对其进行放大处理，推动相应的继电器，最后加到摇机电机以完成规定的动作。打个比方，左前门控制右前门的信号传递过程将是:信号请求传递到舒适中央，舒适中央接到信号后会对信号进行判别，如果这是右前门也传输过来一个请求信号，或者是上升或者是下降信号，那么将会以最后一个到达的请求信号为准，如果左前和右前两个信号同时到达，那么摇机将无动作，这个现象我已经试验过了，有兴趣的同行可以验

证一下。

6)对总线理解比较深入的朋友可能会说，舒适总线下的各个模块应该是平等的关系，也就是说，信号应该是可以从左前门直接传递到右前门的，但我们在处理舒适中央和各个门的关系时，应该按照LIN总线的主从关系去理解才是正确的，也就是说，各个门的请求信号的最终执行与否将取决于舒适中央，认识到这一点是很有必要的，这正是我发这个帖子

的原因，它有助于我们采用更为准确和便捷的诊断方式迅速地解决问题。

透过事物的现象看本质是所有维修人员永恒的主题，特发此贴与大家共勉。

由于没有POLO的电路图文件，特发PASSAT2.8V6的舒适系统电路图给大家，它的系统其实和POLO是一样的，而且更为完善，有兴趣的朋友可结合我的案例看看，对大家一

定是有帮助的。

Vertically split casing pump body should not be removable and

washable. 3.8.1.4 pumps shall conform to the technical level of vertical

and horizontal documents. If there is no provision, in General, the

following requirements: the overall installation of pumps, axial

horizontal deviation of not more than 0.1/1000 horizontal deviation is

less than 0.2/1000; level the measurement flange should be on a level

surface or on the horizontal surface of the pump body. Disintegration of

the installation of the pump, the level of vertical and horizontal

deviation shall be no greater than 0.05/1000; level of horizontal split

casing, the exposed part of the shaft or base on a level work surface.

3.8.1.5 alignment, the following requirements of the pump: pump and

driven half coupling of radial displacement of the machine-side

clearance, axis tilt shall comply with the technical file requirements.

When provided, must meet the following requirements: ... Coupling

diameter d (mm) radial displacement mm two-axis tilt 0.5/10007~9 of

steam turbine-driven pumps and transport high temperature liquid pumps,

State at room temperature when aligning should be reserved in accordance

with design compensation when its temperature changes. 3.8.1.6 bearing

Assembly check that the pump bearing (thick tile), Watts and Watts

should fit tightly on the back, the interference values such as device

files should be provided as 0.02~0.04mm, bearing and axle journal and

the top layer and the shell should be good, without hierarchy, as it

emerges, the alloy surface and surface layer and surface should be

smooth, free of cracks, pores, skin, slag and scratches, and other

defects. Bearing and journal of exposure should be good, contacts within

the contact should be uniform, no square centimeter 2~4 a point, contact

point shall conform to the technical documents of, such as technical

documentation not required, you should comply with the following

requirements: when diluted oil lubrication, the tile on contact angle of

130 ?, contact