Method to write requests on a vehicle diagnostic bus

A plug-in device configured to:

• /a/ detect a Bus Active condition, either via an electrical pin on the diagnosis plug or via an analysis of activity level on at least one Diagnosis bus accessible at the diagnosis plug,
• /b/ cause the diagnosis plug-in device to listen only on the at least one Diagnosis bus after the Bus Active condition is detected,
• /c/ determine a write enable condition, according to evolution of bus load level on the at least one diagnosis bus and/or after a certain time elapsed since the Bus Active condition was true, wherein the write enable condition is set to not become true before a listen-only period of time since the Bus Active condition was true, and the listen-only period of time DT1 is predefined and comprises between 1 second and 20 seconds, wherein no request is sent on the Diagnosis bus by the diagnosis plug-in device during the listen-only period of time,
• /e/ whenever the write enable condition becomes true, carry out, at the diagnosis plug-in-device, firstly a Vehicle Identification Number query request (Q-VIN) and then one or more request/answer services to write requests on the diagnosis bus and retrieve, in the corresponding answers, various data from one or more on-board Electronic Control Units, to be decoded and forwarded to a client fleet management system, via a host server.

A system comprising at least a diagnosis plug-in device connected to the diagnosis plug of a vehicle, a host server, one or more on-board Electronic Control Units coupled to the diagnosis plug, wherein the diagnosis plug-in device is wireless coupled to the host server where the system configured to:

• /a/ cause detection, at the diagnosis plug-in device, of a Bus Active condition, either via an electrical pin on the diagnosis plug or via an analysis of activity level on at least one Diagnosis bus accessible at the diagnosis plug,
• /b/ cause the diagnosis plug-in device to listen only on the at least one Diagnosis bus after the Bus Active condition is detected,
• /c/ determine, at the diagnosis plug-in device, a write enable condition, according to evolution of bus load level on the at least one diagnosis bus and/or after a certain time elapsed since Bus Active condition was true, wherein the write enable condition is set to not become true before a listen-only period of time since the Bus Active condition was true, and the listen-only period of time DT1 is predefined and comprises between 1 second and 20 seconds, wherein no request is sent on the Diagnosis bus by the diagnosis plug-in device during the listen-only period of time,
• /e/ whenever the write enable condition becomes true, carry out, at the diagnosis plug-in device, firstly a Vehicle Identification Number query request (Q-VIN) and then the request/answer services to write requests on the diagnosis bus and retrieve, in the corresponding answers, various data from the one or more on-board Electronic Control Units, to be decoded and forwarded to a client fleet management system, via the host server.

A method carried out in a system, the system comprising at least a diagnosis plug-in device connected to the diagnosis plug of a vehicle, a host server, one or more on-board Electronic Control Units coupled to the diagnosis plug, wherein the diagnosis plug-in device is wireless coupled to the host server, the method comprising the following steps:

• /a/ detect, at the diagnosis plug-in device, a Bus Active condition, either via an electrical pin on the diagnosis plug or via an analysis of activity level on at least one Diagnosis bus accessible at the diagnosis plug,
• /b/ cause the diagnosis plug-in device to listen only on the at least one Diagnosis bus after the Bus Active condition is detected,
• /c/ determine, at the diagnosis plug-in device, a write enable condition, according to evolution of bus load level on the at least one diagnosis bus and/or after a certain time elapsed since Bus Active condition was true, wherein the write enable condition is set to not become true before a listen-only period of time since the Bus Active condition was true, and the listen-only period of time DT1 is predefined and comprises between 1 second and 20 seconds, wherein no request is sent on the Diagnosis bus by the diagnosis plug-in device during the listen-only period of time,
• /e/ whenever the write enable condition becomes true, carry out, at the diagnosis plug-in device, firstly a Vehicle Identification Number query request (Q-VIN) and then one or more request/answer services to write requests on the diagnosis bus and retrieve, in the corresponding answers, various data from the board Electronic Control Units, to be decoded and forwarded to a client fleet management system, via the host server,
• further comprising the step of
• /d2/ determining vehicle type, wherein for certain particular vehicle type, the write enable condition is disabled,
• wherein the step of determining vehicle type is made from a frame profile determined according to characteristics of the received frame-IDs on the diagnosis bus.