| 摘要 |
PROBLEM TO BE SOLVED: To diagnose a failure in a water temp. sensor, for accurately sensing the temp. of an engine cooling water early, after the engine is started. SOLUTION: A water temp. sensor 29 is installed facing a water jacket 40 formed at a cylinder block of an engine body. A soak timer 33, actuated with the backup voltage after an ignition switch, is put off and to measure the stop time of the engine 1 is installed in an engine control unit 30 which covers the engine 1 control operations including fuel injection, ignition timing, and idling speed. When the sensed temp. of the water temp. sensor 29 at the start of the engine 1 is higher than a prescribed level, when the measuring time of the soak timer 33 is longer than the specified value, the engine control unit 30 passes makes the diagnosis that a high-tack phenomenon in which the sensor 29 fixed to the high temp. side and lights up an alarm lamp in the cabin to inform the driver of the occurrence of the failure.
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