Vehicle diagnostic method based on mode $06 and in-use monitor performance ratio data

An automotive diagnostic method aimed at focusing diagnostic data retrieval and analysis on a possible fault condition, the method comprising the steps of:

• receiving vehicle data from a vehicle using a data acquisition and transfer device (DAT);
• identifying a drive cycle associated with the possible fault condition;
• monitoring driving conditions using the DAT to identify completion of the identified drive cycle;
• upon the completion of the identified drive cycle, analyzing the vehicle data on the DAT to identify an abnormal monitor;
• and
• analyzing the vehicle data to identify an In-Use Monitor Performance Ratio (IUMPR) associated with the abnormal monitor, including calculating an IUMPR ratio and comparing the IUMPR ratio to a predetermined threshold;
• when an abnormal value of IUMPR is identified, identifying a likely diagnostic condition associated with the identified abnormal value of IUMPR;
• when a normal value of IUMPR is identified, further comprising the step of retrieving Mode $06 data;
• reviewing, by the DAT, the Mode $06 data for an abnormal test result and identifying a component associated with the abnormal test result;
• issuing an electronic OBD-II control command to initiate a Special Test for the identified component;
• generating a wireless message to a remote electronic device including at least a vehicle identification number (VIN), a monitor ID, a test ID, an IUMPR ratio value, and timestamps for the completion of the identified drive cycle and execution of the Special Test;
• wherein the DAT:
• (i) identifies the completion of the identified drive cycle by querying a vehicle electronic control unit (ECU) using OBD-II service $01, PID $41 to read monitor readiness status;
• and (ii) computes the IUMPR by querying OBD-II service $09, PID $08 and/or PID $0B to obtain conditions and completion counters and performing the ratio and threshold comparison locally at the DAT;
• wherein all steps following the receipt of the vehicle data occur autonomously in response to the receipt of the vehicle data;
• and
• wherein all steps following the completion of the identified drive cycle occur autonomously in response to the completion of the identified drive cycle.

A data acquisition and transfer device (DAT) for automotive diagnostics, the DAT comprising interface circuitry configured to communicate with a vehicle electronic control unit (ECU), a processor, and non-transitory memory storing instructions that, when executed by the processor, cause the DAT to:

• receive vehicle data from the ECU;
• analyze the vehicle data to identify a possible fault condition, including at least one of:
• evaluating diagnostic trouble code (DTC) data and evaluating live vehicle data;
• monitor driving conditions to detect completion of an identified drive cycle associated with the possible fault condition, including querying OBD-II service $01, PID $41 to read monitor readiness status;
• upon the completion of the identified drive cycle, analyze the vehicle data to detect an abnormal monitor;
• compute, locally at the DAT, an In-Use Monitor Performance Ratio (IUMPR) for the abnormal monitor by determining a numerator that represents a number of times all monitoring conditions necessary for the monitor to detect a malfunction have been encountered, determining a denominator that represents a number of times a vehicle has been operated under defined conditions for a standard drive cycle, calculating a ratio of the numerator to the denominator, and comparing the ratio to a threshold, including querying OBD-II service $09, PID $08 and/or PID $0B to obtain IUMPR counters;
• when the IUMPR is normal, retrieve Mode $06 data, identify at least one of an OBD on-board diagnostic monitor identifier (OBDMID) and a test identifier (TID), and identify a component associated with an abnormal Mode $06 test result;
• and
• issue an electronic OBD-II control command to initiate a Special Test for the identified component, wherein actions following receipt of the vehicle data occur autonomously in response to the receipt of the vehicle data, and actions following the completion of the identified drive cycle occur autonomously in response to the completion of the identified drive cycle, and wherein the DAT is further configured to generate a wireless message to a remote electronic device including at least a vehicle identification number (VIN), a monitor ID, a test ID, an IUMPR ratio value, and timestamps for the completion of the identified drive cycle and execution of the Special Test.