Automotive Diagnostic System

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.

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.