An intake air cooling apparatus abnormality detection system for an engine includes a first intake air temperature sensor that detects an intake air temperature in an intake pipe at the downstream side of an intercooler and a second intake air temperature sensor that detects the intake air temperature in an intake manifold. An abnormality determination unit determines that an abnormality occurs in an intercooler cooling water circuit if a state in which at least one of a value based on an output from the first intake air temperature sensor and a value based on an output from the second intake air temperature sensor exceeds a predetermined threshold value continues for a certain time or longer when a load state determination unit determines that the engine is in a high load state.

Diagnostic systems and methods for a surge valve that selectively bypasses a compressor of a turbocharger of an engine involve receiving, by a controller, a barometric pressure signal indicative of a barometric pressure external to the engine, receiving, by the controller, a throttle inlet pressure (TIP) signal indicative of an air pressure at an inlet of a throttle valve of the engine and downstream from the surge valve and the compressor, and performing, by the controller, a diagnostic technique on the surge valve, the diagnostic technique comprising generating a pressure ratio signal that is a ratio of the TIP signal to the barometric pressure signal, applying a high-pass filter to the pressure ratio signal to obtain a filtered pressure ratio signal, and based on a quantity of detected pulses in the filtered pressure ratio signal that exceed the diagnostic threshold, detecting a malfunction of the surge valve.

The occurrence of the misfire having a level at which exhaust purifying function of a catalyst is impaired (OT-level misfire) is detected. Upon the detection of the OT-level misfire, basic OT risk from the misfire is multiplied by a correction coefficient corresponding to the accumulated PM amount on the catalyst. The basic OT risk from the misfire is a basic value of OT risk from the misfire which is set based on the operating condition of the engine. The correction coefficient is set to a smaller value as the accumulated PM amount increases. Therefore, the OT risk from the misfire after the multiplication decreases as the accumulated PM amount increases. When a predetermined judgement condition with the OT risk from the misfire is established, it is judged that the misfire having the level occurs.

Disclosed is a method for estimating a physical stoppage of an engine of a motor vehicle, subject to bounce-back, a target equipped with teeth being borne by the crankshaft and successive passes of the teeth past a sensor being detected, a first time count incrementing since a last detection of the passing of a tooth and being associated with a first time threshold with the first count being reset to zero when the time between passes of two successive teeth is below the first threshold. A second count associated with a second time threshold is performed, with this count being suspended when and for as long as a time between the passes of two successive teeth is below the second threshold, the engine being estimated to have stopped as soon as the counts have respectively reached the first and second thresholds.

An automatic calibration method capable of adapting the set of conditions for performing hardware diagnostics, in an OBD system, with a view to optimizing the compromise between the number of diagnostics performed, in particular in order to comply with legislation relating to the ratio between the number of diagnostics performed on a component and the number of operating cycles, and the accuracy of the diagnostics.

Methods and systems are provided for diagnosing temperature sensors of a vehicle. In one example, a method may include, at a duration after an engine-off event, determining that an intake air temperature measured by an intake air temperature sensor of the vehicle is less than an ambient air temperature measured by an ambient air temperature sensor of the vehicle. In response to the determining, the method may include flowing air from a catalyst across the intake air temperature sensor; and indicating the intake air temperature sensor is functional responsive to the intake air temperature converging to the ambient air temperature during the flowing.

An outboard motor includes a plurality of electric actuators including an electric steering actuator and an electric tilt actuator, a power-source voltage detector that detects a power-source voltage in the outboard motor, an ECU, and a memory. If a power-source voltage detected by the power-source voltage detector becomes lower than a predetermined threshold value and if the plurality of electric actuators are simultaneously driven, the ECU determines that a voltage variation event has occurred. Event information including the number of occurrences of the voltage variation event is recorded in the memory.

Methods and systems are provided for detecting spark plug fouling and cleaning up fouled spark plug during pre-delivery phase of a vehicle. In one example, a method may include updating a spark plug fouling index saved in the non-volatile memory of the vehicle based on engine operating parameters, and indicating spark plug fouling based on the updated index. The method may further include cleaning the fouled spark plug by driving the vehicle along a planned route.

A misfire determination apparatus includes a rotation variation amount acquisition unit that obtains a rotation variation amount (NE), which is a difference between a first angular velocity variation amount (1) obtained during an expansion stroke of an arbitrary cylinder of a multi-cylinder internal combustion engine and a second angular velocity variation amount (2) having been obtained in relation to a cylinder that has reached the expansion stroke N (where N is a positive integer) revolutions of a crankshaft before the arbitrary cylinder reaches the expansion stroke, and a misfire determination unit that, when the obtained rotation variation amount (NE) exceeds a predetermined threshold (NEth), determines that a misfire has not occurred in the internal combustion engine when a predetermined condition is established, and determines that a misfire has occurred in the internal combustion engine when the predetermined condition is not established.

An in-vehicle device is an in-vehicle device mounted on a vehicle and to provide with a driving unit, the device including: a control unit controlling the driving unit; and a communication unit for communicating with an in-vehicle ECU to be mounted on the vehicle, in which when an inhibition event for inhibiting diagnosis processing of the driving unit is detected at the time of performing the diagnosis processing, the control unit outputs a detection result notification indicating that the inhibition event is detected to the in-vehicle ECU through the communication unit.