Abstract: A method to diagnose electrical failures of remotely driven inductive loads as well as the failures of electrical connections between a controller and a remotely located power module. Circuitry for diagnosing the fault condition of a plurality of remote inductive loads driven by a master module over a corresponding plurality of connection lines. Diagnostic information is mixed or intermodulated onto the connection line for a control signal of a sequential subsequent one of the loads and is transmitting over the connection line from the remote load to the master module for receipt by a controller in the master module. The control signal was not responsible for driving that particular load from which the diagnostic information was taken. The loads are sequentially driven so that the diagnostic information is multiplexed onto the connection lines which aids in helping the controller to recognize the fault condition.

Abstract: A solenoid actuation detection device for detecting actuation of an armature of a solenoid includes a sensor for sensing electric current flowing through a solenoid, a peak detector for receiving the sensing signal and for creating a peak signal from the sensing signal, and a comparator for comparing the two signals to determine when an armature of the solenoid was actuated.

Abstract: A fault detection system detects the existence of unwanted electrical paths between the high voltage traction system of an electric car and the chassis of the car. The fault detection system includes a positive sampling RC circuit connected to the positive conductor of the traction system and a negative sampling RC circuit connected to the negative conductor of the traction system. Each RC circuit generates a voltage, and the voltages are balanced, i.e., the voltages are equal and opposite, when no leakage path exists. In contrast, when a leakage path to chassis exists, the voltages are not balanced. A comparator compares the sum of the voltages to a setpoint which varies proportionately to the varying voltage of the battery of the traction system, and a fault condition is indicated when the sum of the voltages exceeds the setpoint.

Abstract: In a engine and associated fuel injector failure detection circuit, the engine having at least one combustion chamber, a battery, and at least one fuel injector having a high side and a low side terminal for introducing a fuel in the at least one combustion chamber, the fuel injector failure detection circuit comprising a one shot timer for transmitting a constant voltage state signal output when the fuel injector reaches a set current threshold at a start of an injector current peak time duration. A voltage sense comparator is provided for transmitting a low voltage state signal output when the low side terminal of the fuel injector produces a fly-back voltage pulse. A mechanism for monitoring current of the fuel injector during a rise time duration and the peak time duration ia also included.