Automotive Diagnostic System

Abstract

A system and method is presented for diagnosing problems in a sensor, a vehicle computer and a vehicle sensor wiring harness. The diagnostic system comprises a sensor simulator configured to be selectively coupled to the vehicle computer via a wiring harness during a diagnostic mode, and to eliminate and simulate a known good sensor to the vehicle computer by way of the vehicle sensor wiring harness directly connected therebetween. The system includes an external computer adapted to selectively couple the sensor simulator to the vehicle computer, and a user keypad and memory to receive and store user commands of a selected manufacturer's make, model, year of vehicle, and the function type of the selected sensor, and to enable the user to select or adjust a typical operational value comprising one or more of a voltage, current or resistance operational range values of the selected sensor.

What is claimed is: 
     
         1 . An automotive diagnostic system for a vehicle, comprising:
 a sensor simulator, adapted to be selectively coupled during a diagnostic mode to:
 a vehicle computer for the vehicle having a vehicle sensor wiring harness coupled between the sensor simulator and the vehicle computer; 
 an external computer adapted to control the sensor simulator to be selectively coupled to the vehicle computer by way of the vehicle sensor wiring harness and during the diagnostic mode to simulate the operation of a known good sensor without the sensor or any means of connection between the sensor and the automotive diagnostic system; 
 a user keypad coupled to the external computer, and adapted to receive user commands associated with a selected manufacturers make, model, year vehicle, and the function type of the sensor to be simulated by the sensor simulator, and to enable the user to select or adjust a typical operational value of the sensor, and 
 a memory device coupled to the external computer, and adapted to store a range of vehicle manufacturer's makes, models, years, sensor function types, and voltage, current or resistance operational range values of the sensor to be simulated: 
   wherein during a typical vehicle operations mode the vehicle sensor wiring harness is coupled between the vehicle computer and a sensor which is to be simulated.   
     
     
         2 . The automotive diagnostic system of  claim 1 , wherein the automotive diagnostic system further comprises a user interface comprising
 a display configured to display alphanumeric characters or graphics, representing one or more voltage, current and resistance measurements, and sensor operational range values associated with the sensor, and   a plurality of pushbuttons for inputting and changing the sensor operational range values, for selecting one or more operational modes of the automotive diagnostic system, and for configuring one or more options of the automotive diagnostic system.   
     
     
         3 . The automotive diagnostic system of  claim 1 , wherein the automotive diagnostic system further comprises a user interface comprising
 a display configured to display alphanumeric characters or graphics, representing one or more of a vehicle manufacturer's make, model, year, sensor function type, and one or more of a voltage, current or resistance operational range value of the sensor associated with the vehicle, and   a user keypad adapted to receive user commands associated with a selected manufacturers make, model, year vehicle, and the function type of the sensor to be simulated using the sensor simulator, and to enable the user to select or adjust a typical operational value of the sensor to be simulated.   
     
     
         4 . The automotive diagnostic system of  claim 1 , wherein the automotive diagnostic system is further adapted to be selectively coupled during a sensor diagnostic mode, directly to a suspect sensor, to measure and evaluate the health of the sensor, and to provide sensor safety or failure prediction information based on a comparison between the measurements and evaluations of the suspect sensor and the respective stored data of the simulated sensor, thereby providing comparison data that may indicate marginal or changing sensor parameters to help maintain safe vehicle operations by avoiding an impending sensor failure. 
     
     
         5 . The automotive diagnostic system of  claim 1 , wherein the automotive diagnostic system further comprises an at least two position switch configured to select between the simulated sensor output of the sensor simulator and the output of the suspect sensor, the switch further configured to provide the output selection to the vehicle computer by way of the vehicle sensor wiring harness. 
     
     
         6 . A method of diagnosing problems in a suspect sensor, a vehicle sensor wiring harness and a vehicle computer of a vehicle without any connection to the sensor by replacing and simulating the operation of a known good sensor as a simulated sensor, using an automotive diagnostic system comprising a sensor simulator configured to be selectively coupled to the vehicle computer by way of the vehicle sensor wiring harness coupled therebetween during a diagnostic mode, the method comprising:
 disconnecting the suspect sensor from the vehicle sensor wiring harness of the vehicle;   connecting the vehicle sensor wiring harness between the sensor simulator and the vehicle computer;   receiving user commands of one or more of a manufacturers make, model, year vehicle, and function type, and one or more voltage, current or resistance operational range values associated with the suspect sensor;   selecting or adjusting the sensor simulator to an operational range value for the known good sensor;   generating and outputting at least one of the one or more operational range values and a simulation from the sensor simulator to the vehicle computer by way of the vehicle sensor wiring harness during the diagnostic mode;   diagnosing that a problem exists in the suspect sensor and that the vehicle computer and the vehicle sensor wiring harness are OK, if it is determined that the simulated operation of the known good sensor as presented to the vehicle computer indicates that the simulated sensor is OK; and   diagnosing that a problem exists in the vehicle sensor wiring harness or in the vehicle computer, if it is determined that the simulated operation of the known good sensor as presented to the vehicle computer indicates that the simulated sensor is not OK.   
     
     
         7 . The method of  claim 6 , further comprising
 diagnosing that a problem exists in the vehicle sensor wiring harness by first determining that the vehicle computer is ok, by using a diagnostic scanner tool to determine the acceptable operations of several functions or sensors not associated with the suspect sensor; and then   determining if the simulated operation of the known good sensor as presented to the vehicle computer indicates that the simulated sensor is not OK.   
     
     
         8 . The method of  claim 6 , further comprising
 storing a vehicle manufacturer's make, model, year, sensor function type, and one or more of a voltage, current or resistance operational range value of the suspect sensor in a memory device coupled to an external computer.