idle air control valve for a nissan sentra
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Filed Under (Oldsmobile) by admin on 10-04-2011
Refer to Engine Controls Schematics MAF, Secondary Air Injection Pump Bypass Solenoid, IAC and Secondary AIR Pump . Circuit Description The AIR pump is used on this vehicle to lower tail pipe emissions on start-up. The powertrain control module (PCM) grounds the AIR pump relay control circuit, which energizes the AIR pump. The PCM also grounds the AIR solenoid valve control circuit, which energizes the AIR solenoid valve. The AIR solenoid valve opens allowing manifold vacuum to open the AIR control valves. The PCM enables both control circuits when AIR system operation is desired. When the AIR system is active, the AIR pump forces fresh air into the exhaust stream in order to accelerate catalyst operation. The AIR control valves replace the conventional check valves. When the AIR system is inactive, the AIR control valves prevent air flow in either direction. DTC P0412 applies to the AIR solenoid control circuit. DTC P0418 applies to the AIR pump relay control circuit. DTC P0410 sets if an air flow problem is detected. The PCM will run two tests using the heated oxygen sensor (HO2S) voltage to diagnose the AIR system. Both tests have two parts. The passive test is performed during regular AIR pump operation. The passive test consists of the following: Passive Test Part 1 When the AIR system is enabled, the PCM monitors the HO2S voltage. If the HO2S voltage goes below a threshold, the PCM interprets this as an indication that the AIR system is operational. Passive Test Part 2 When the AIR system is disabled, the PCM monitors the HO2S voltage. The HO2S voltage should increase above a threshold and switch normally. If both of these tests indicate a pass, no further action is taken. If one of the above tests failed or is inconclusive, the diagnostic will proceed to test two. The active test is performed specifically for diagnostic purposes. Test two consists of the following: Active Test Part 1 During this test the PCM turns the AIR system on during closed loop operation. When the AIR system is activated, the PCM monitors the HO2S voltage. If the AIR system is operating properly, the HO2S voltage should go below a predetermined threshold. Active Test Part 2 The PCM turns the AIR system off. The HO2S voltage should return to above a rich threshold.
Filed Under (Honda) by admin on 21-12-2010
NOTE: If DTC P1519 is stored at same time as DTC P0505, troubleshoot DTC P1519 first, then recheck for DTC P0505. 1. Start the engine. Hold the engine at 3,000 rpm with no load (in Park or neutral) until the radiator fan comes on. 2. Check the engine speed at idle with no-load conditions: headlights, blower fan, rear window defogger, radiator fan, and air conditioner off. Is the engine running at 730+/-50 rpm? YES – Intermittent failure, system is OK at this time.? NO – If the idle speed is less than 680 rpm, go to step 3; if it’s 780 rpm or higher, go to step 4. 3. Disconnect the idle air control (IAC) valve 3P connector. Does the engine speed increase or fluctuate? YES – Adjust the idle speed. If the idle will not adjust properly, clean the passage in the throttle body, and then adjust the idle.? NO – Replace the IAC valve.? 4. Turn the ignition switch OFF. 5. Remove the intake air duct from the throttle body. 6. Start the engine and let it idle. 7. Put your finger on the lower port (A) in the throttle body. Does the engine speed drop below 780 rpm? YES – Adjust the idle speed. If the idle will not adjust properly, replace the IAC valve, and then adjust the idle.? NO – With the throttle valve completely closed, check for vacuum leaks, and repair as necessary.?
Filed Under (GM) by admin on 03-11-2010
Located on the throttle body, the Idle Speed Control (ISC) valve opens the air bypass passage when the solenoid is ON and closes it when the solenoid is “OFF.” The ECM turns the ISC solenoid ON and OFF at a constant cycle of 20 times per second. It controls the bypass air flow by making “ON” time one cycle shorter or longer depending on conditions. In this system, the ECM controls the ISC solenoid valve according to the signals from various sensors and switches to control the bypass air flow which plays the following three roles as required by certain circumstances. IDLE-UP AIR FLOW When head lights & other lights, heater fan, rear defogger (if equipped) or air conditioner (if equipped) are operating, and/or the automatic transmission is in a range other than PARK or NEUTRAL, and/or the vehicle is at high altitudes, higher than 8,200 ft or 2,500 m, the bypass air is supplied to stabilize the engine idle speed. How much air is supplied varies depending on the load. When head lights and other lights are ON, the idle speed rises only a little higher than the normal specified idle speed (920 rpm). AFTER START AIR FLOW When and after the engine is started, the bypass air is supplied to prevent the engine from stopping when the throttle opener is OFF and to improve the engine performance at its start. How much bypass air is supplied varies depending on the engine cooling water temperature and it decreases as time passes when engine is cool. When engine is hot and 15 seconds have passed after engine starts, a given amount of bypass air is supplied until either the idle switch is turned OFF from ON once or engine speed exceeds 1,500 rpm once. DASHPOT AIR FLOW A sudden change in the throttle valve opening (especially when decelerating) causes the air/fuel mixture ratio to change suddenly. To compensate for this condition, the bypass air flow will be increased or decreased depending on condition. By increasing or decreasing the air, the air/fuel mixture ratio is changed gradually and dashpot effect is obtained. The air is increased when throttle is opened and decreased when the throttle is closed.
Filed Under (Subaru) by admin on 02-01-2011
Removal of Factory Intake 1. 2. Turn the ignition OFF and disconnect the vehicle’s negative battery cable. Loosen and remove the two bolts that secure the air inlet duct to the radiator core support, then remove the air inlet duct. Loosen the clamps at the air cleaner assembly and turbo inlet tube, then remove the stock intake tube. Loosen and remove the two bolts that secure the air cleaner assembly. Pull upwards to remove the air cleaner assembly. Using the bolt removed to secure the ABS control bracket. Loosen and remove the two screws that secure the mass air sensor to the air cleaner assembly, then remove the mass air sensor. Raise the vehicle and support with the jack stands, then remove the front passenger side tire. Remove the five plastic push/screw clips that secure the inner wheel house valance. Remove the 6 screw in push clips that secure the air duct to the lower valance, then remove the air duct. Remove the two remaining push clips that secure the lower valance, then pull the valance down. From inside the apron, remove the push clip that secures the apron to the upper fender. Remove the hex nut that secures the air intake resonator to the inner fender. Loosen and remove the second hex nut that secures the air intake resonator from underneath the vehicle. Remove the air intake resonator. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. Install of Intake 16. Install the reducer and clamps onto the turbo and secure. 17. Loosen and remove the hex bolt on the cam cover. 18. Using the provided allen bolts, secure the mass air sensor into the adapter on the intake tube. 19. Using the allen bolts, secure the mass air sensor into the adapter on the intake tube. 20. Slide the intake tube into the reducer and secure the mass air sensor into the adapter on the intake tube. 21. Tighten the clamp on the intake tube. 22. Install the reducer and clamps onto the intake tube. 23. From underneath the vehicle loosen and remove the hex nut that secures the ABS pump to the inner fender. 24. Slide the cold air tube intake tube from underneath the vehicle into the hole in the inner fender, then line up the bracket with the ABS bolts, and tighten with the nut remove. 25. Slide the reducer onto the cold air intake tube. 26. Install the Bomz Filtercharger onto the cold air intake tube and secure with clamp. 27. Reverse the removal process for the plastic wheelhouse valance and air duct with the stock push clips. 28. Reconnect the mass air sensor electrical connection. 29. Reconnect the negative battery cable and double check to make sure everything is tight before starting the vehicle. Resetting the ECU This is to be completed at your own risk. This procedure will reset the computer so that it may “learn” of your new intake. We are not to be held liable for any mishaps that you may occur while completing this process. • • Disconnect the Negative battery cable for 5 minutes. Reconnect the battery cable and false panel cover.
Filed Under (volkswagen) by admin on 30-06-2011
SYSTEM OPERATION CHECK An air bag light is located on left side of instrument cluster. Air bag light is used to indicate readiness of system. Light glows when ignition switch is on or engine is started. Light should stay on about 3 seconds while air bag control unit performs an electronic test of system. If air bag light does not glow when ignition is on or does not go out after 3 seconds, a fault probably exists in system. If a fault occurs while ignition is on, it is stored in fault memory. Warning light will then glow and air bag system will be switched off. If warning light glows or flickers while driving, air bag system should be tested. See DIAGNOSIS & TESTING in appropriate AIR BAG RESTRAINT SYSTEM article in ACCESSORIES/SAFETY EQUIPMENT section. * * ADJUSTMENTS AIR BAG SPIRAL SPRING To center spiral spring assembly, turn spring assembly 3 turns from stop in either direction. REMOVAL & INSTALLATION WARNING: Failure to follow air bag service precautions may result in air bag deployment and personal injury. See SERVICE PRECAUTIONS. After component replacement, perform a system operational check to ensure proper system operation. See SYSTEM OPERATION CHECK. AIR BAG MODULE Removal 1) Before proceeding, follow air bag service precautions. See SERVICE PRECAUTIONS. Disable air bag system. See DISABLING & ACTIVATING AIR BAG SYSTEM. 2) Air bag module is located in steering wheel. See Fig. 1. Remove air bag module Torx head screws from rear of steering wheel. Lift off air bag module from steering wheel, and tilt air bag module downward. Disconnect air bag module connector. AIR BAG RESTRAINT SYSTEM – 1995 AIR BAG RESTRAINT SYSTEM – 1996