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CRUISE OR IDLE MODE When the engine is at operating temperature, this is a CLOSED LOOP mode. During cruising speed the • knock sensor • manifold absolute pressure • engine speed (crankshaft position sensor) • throttle position • exhaust gas oxygen content • A/C control positions • battery voltage The PCM provides a ground path for the injectors to precisely control injector pulse width. The PCM adjusts ACCELERATION MODE This is a CLOSED LOOP mode. The PCM recognizes an abrupt increase in throttle position or MAP pres- DECELERATION MODE This is a CLOSED LOOP mode. During deceleration the following inputs are received by the PCM: • knock sensor • manifold absolute pressure • engine speed (crankshaft position sensor) • throttle position • exhaust gas oxygen content • A/C control positions • battery voltage The PCM may receive a closed throttle input from the throttle position sensor (TPS) at the same time it WIDE OPEN THROTTLE MODE This is an OPEN LOOP mode. During wide-open- throttle operation, the following inputs are received • knock sensor • manifold absolute pressure • engine speed (crankshaft position sensor) • throttle position When the PCM senses a wide open throttle condi- tion it will de-energize the air conditioning relay. The exhaust gas oxygen content input is not ac- cepted by the PCM during wide open throttle opera- IGNITION SWITCH OFF MODE This is an OPEN LOOP mode. When the ignition switch is turned to the OFF position, the following • No inputs are monitored. • The PCM shuts down. Fig. 20 Throttle Body Ä FUEL SYSTEMS 14 - 93 |