Method and system for retrieving diagnostic information from a vehicle

An off-board device (OBT) comprising:

• a processor in circuit communication with a) vehicle communication circuitry for linking to a vehicle diagnostic system, requesting information from the vehicle diagnostic system, and receiving information from the vehicle diagnostic system;
• b) host interface circuitry for communicating with a host computer;
• and
• c) logic for transmitting one or more unsolicited messages to the host computer.

An OBT comprising:

• a processor in circuit communication with
• a) vehicle communication circuitry for linking to a vehicle diagnostic system, wherein the vehicle diagnostic system comprises one or more computer modules;
• b) logic for requesting information from the vehicle diagnostic system;
• c) logic for receiving the information from the vehicle diagnostic sytem;
• d) logic for determining the minimum number of messages to expect from each of the one or more computer modules in response to a request for data;
• and
• e) logic for determining whether the number of minimum number of messages have been received from each module.

An automobile emissions inspection system comprising:

• a) a host computer;
• and
• b) an OBT comprising;
• i) logic for establishing a communications link with a vehicle diagnostic system using a selected communications protocol;
• ii) logic for receiving a request for data from the host computer;
• iii) logic for requesting data from the vehicle diagnostic system;
• iv) logic for re-establishing communications with the vehicle diagnostic system using the selected communications protocol.

A method of determining whether to establish circuit communications with a vehicle diagnostic system comprising:

• connecting an OBT to a vehicle diagnostic system;
• obtaining a measurement indicative of the voltage of the vehicle battery;
• determining whether the measured voltage is above a first threshold value;
• establishing a communications link with the vehicle if the measured voltage is above a first threshold value;
• and
• providing an output if the measured voltage is below the second threshold value.

A method of establishing a communications link between an OBT and a vehicle diagnostic system comprising:

• obtaining a vehicle type;
• determining whether the vehicle type is a problem vehicle type;
• if the vehicle type is not a problem vehicle automatically determining a preferred communications protocol by communicating with the vehicle;
• if the vehicle type is a problem vehicle type, obtaining a communications protocol associated with the vehicle type without communicating with the vehicle;
• and
• establishing a communications link with the vehicle diagnostic system.

A method of re-establishing communications between an OBT and a vehicle diagnostic system comprising:

• establishing a communications link with a vehicle diagnostic system;
• storing a communications protocol used to link with the vehicle diagnostic system;
• determining loss of communications between the OBT and the vehicle diagnostic system;
• re-establishing the communications link using the stored communications protocol.

A method of communicating unsolicited messages from an OBT to a host computer comprising:

• connecting the OBT to a vehicle diagnostic system;
• establishing a communications link with the vehicle diagnostic system;
• receiving a request for data from the host computer;
• sending an unsolicited message to the host computer;
• requesting the data from the vehicle diagnostic system;
• and
• sending the retrieved data to the host computer.

A method of decreasing the time required to perform an inspection maintenance test comprising:

• determining the number of computer modules in a vehicle diagnostic system;
• determining the number of messages to expect from each computer module in response to a data request;
• creating a table with the number of computer modules that support a data request and the minimum number of messages to expect from each computer module;
• sending a data request to the vehicle diagnostic system;
• determining whether the minimum number of messages have been received for each computer module;
• if the minimum number of messages have been received for each module, proceeding with test;
• if the minimum number of messages have not been received for each module, waiting for a time-out period to expire.

An OBT comprising:

• a processor in circuit communication with
• a) vehicle communication circuitry configured to selectively communicate with a vehicle diagnostic system to request at least one bit of information from the vehicle diagnostic system and to receive the at least one bit of information;
• b) host interface circuitry for communicating with a host computer;
• and
• c) voltage determination circuitry configured to selectively communicate with the starter/charging system to test at least one of a starting system, a charging system and a battery via a test cable connected to the vehicle diagnostic system.