故障现象一辆厦门金旅客车(车辆型号为XML6125J15CN),装配玉柴YC6G260N-50天然气发动机、威帝CAN总线及特尔佳电涡流缓速器。该车因缓速器不工作在其他服务站进行维修,先后更换了总线主站模块、顶从站模块、前从站模块及仪表也未能将故障排除。故障诊断接车后试车,缓速器确实不工作。该车缓速器控制电路如图1所示,缓速器工作的必要条件包括:缓速 Fault phenomenon A Xiamen Golden Traveler (vehicle model XML6125J15CN), equipped with Yuchai YC6G260N-50 natural gas engine, Wei Di CAN bus and Terjia electric eddy current retarder. The car did not work due to the retarder in other service stations for maintenance, has replaced the bus master module, top slave module, the former slave modules and instruments failed to troubleshooting. After the fault diagnosis test car, retarder does not work. The car retarder control circuit shown in Figure 1, the retarder necessary conditions include: retarder