| 摘要 |
A failure diagnosis apparatus for an exhaust pressure sensor for detecting the exhaust pressure in an exhaust gas recirculation passage which connects an exhaust passage and an intake passage of an internal combustion engine. A first preliminary determination that the exhaust pressure sensor is normal, is made when the engine is in a predetermined low load operating condition and a difference between the detected exhaust pressure and the atmospheric pressure is equal to or less than a first determination threshold value. A second preliminary determination that the exhaust pressure sensor is normal, is made when the engine is in a predetermined high load operating condition and the difference between the exhaust pressure detected by the exhaust pressure sensor and the atmospheric pressure is equal to or greater than a second determination threshold value. A final determination that the exhaust pressure sensor is normal, is made when both of the first and second preliminary determinations are made.
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