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Basic Inspection: Q45

NOTE: Use the following procedure to check and adjust throttle position switch, ignition timing and idle speed. Ensure no Diagnostic Trouble Codes (DTCs) exist before performing test. See SELF-DIAGNOSTICS - INTRODUCTION article. Ensure transmission is in Park or Neutral, all electrical accessories (headlights, A/C, rear window defogger, cooling fan, etc.) are turned off and steering wheel is in straight-ahead position.
  1. Check the following:
    • Harness connectors for poor connections.
    • Vacuum hoses for leaks, kinks or misrouting.
    • Wiring for improper connections, pinches and cuts.

    Repair as necessary. Go to next step.

  2. Start engine and let it idle. Check for clearance between throttle drum and throttle opener rod. See Fig 1. If clearance exists, go to step  4. If clearance does not exist, check vacuum supply to throttle opener. Vacuum should be more than 11.8 in. Hg. Replace vacuum hose or clean intake manifold port as necessary. If vacuum supply is okay, go to next step.
  3. Turn ignition off. Using a hand vacuum pump, apply at least 11.8 in. Hg of vacuum to throttle opener. Throttle opener rod should move more than.065" (1.65 mm) and throttle opener rod should not contact throttle drum. See Fig 1. If operation is as specified, go to next step. If operation is not as specified, replace throttle opener. Go to next step.
  4. Start engine and warm to normal operating temperature. Check for clearance between fast idle cam and roller. See Fig 2. If clearance exists, go to step  8. If clearance does not exist, go to next step.
  5. Remove throttle body from engine. Wait at least 3 hours to bring temperature of thermo element to room temperature. Record room temperature, and measure length (L) of thermo element plunger. See Fig 3.
  6. If length is not within specification, replace thermo element. If length is within specification, measure clearance between stopper and throttle adjusting screw. See Fig 2. To adjust, loosen lock nut, and turn adjusting screw. DO NOT turn throttle adjusting screw.
  7. After adjustment, tighten adjusting screw lock nut to 13-17 INCH lbs. (1.5-2.0 N.m). Reinstall throttle body. Start engine and warm to normal operating temperature. Ensure there is clearance between fast idle cam and roller. Go to next step.
  8. Start engine and warm to normal operating temperature. Turn ignition off. Disconnect TP sensor harness connector. See Fig 4. Start engine. Check ignition timing. See BASE IGNITION TIMING  table. If timing is within specification, go to next step. If timing is not within specification, adjust ignition timing by rotating Camshaft Position (CMP) sensor. See Fig 5.
  9. Check idle speed. Idle speed should be 550-650 RPM with transmission in Park or Neutral. If idle speed is as specified, go to next step. If idle speed is not as specified, turn idle speed screw. See Fig 6. Go to next step.
  10. Warm engine to normal operating temperature. Ensure clearance exists between fast idle cam and roller. See Fig 2. Turn ignition off. Disconnect vacuum hose from throttle opener. Using a hand vacuum pump, apply vacuum to throttle opener until throttle drum does not contact throttle opener rod.
  11. Disconnect TP switch harness connector located next to TP sensor harness connector. See Fig 4. Check continuity between TP switch terminals No. 6 and 8, with specified feeler gauges inserted between throttle drum and throttle adjusting screw. See Fig 7 and Fig 8 . See FEELER GAUGE THICKNESS  table. If continuity is as specified, go to step  14. If continuity is not as specified, go to next step.
  12. Loosen TP sensor mounting bolts. Insert.008" (.20 mm) feeler gauge between throttle drum and throttle adjusting screw. Check continuity between TP switch terminals No. 6 and 8. Open and close throttle. Rotate TP sensor until continuity does not exist when throttle is closed. Slowly rotate TP sensor clockwise until continuity exists, and tighten TP sensor bolts.
  13. Open and close throttle a few times to ensure that continuity exists when throttle is closed and does not exist when throttle is open. Remove.008" (.02 mm) feeler gauge, and insert.012" (.30 mm) feeler gauge. Open and close throttle a few times to ensure that continuity does not exist when throttle is closed. Go to next step.
  14. Reconnect all harness connectors. Start engine and warm to normal operating temperature. Quickly increase engine speed to 3000 RPM 3 times. Let engine idle. Turn ignition off. Go to next step.
  15. Turn ignition on and wait at least 5 seconds. Turn ignition off and wait at least 5 seconds. Repeat 20 times to reset TP sensor idle position memory. Go to next step.
  16. Turn ignition off. Remove vacuum pump, and reconnect vacuum hose to throttle opener. Start engine and check idle speed. Idle speed should be 600-700 RPM with transmission in Park or Neutral. If idle speed is as specified, go to step  18. If idle speed is not as specified, go to next step.
  17. Disconnect TP sensor harness connector. See Fig 4. Turn idle speed screw until idle speed is 550-650 RPM. See Fig 6. Reconnect TP sensor harness connector. Go to next step.
  18. Test is complete. Erase any DTCs in ECM and Transmission Control Module (TCM) that may have been set by performing test.
Fig 1: Retracting Throttle Opener (Q45)
G99H08858Courtesy of NISSAN MOTOR CO., U.S.A.
Fig 2: Adjusting Fast Idle Cam (Q45)
G99I08854Courtesy of NISSAN MOTOR CO., U.S.A.
Fig 3: Measuring Thermo Element Plunger Length (Q45)
G97J06558Courtesy of NISSAN MOTOR CO., U.S.A.
Fig 4: Locating TP Sensor Connector (Q45)
G99G05920Courtesy of NISSAN MOTOR CO., U.S.A.
Fig 5: Locating CMP Sensor (Q45)
G97H06595Courtesy of NISSAN MOTOR CO., U.S.A.
Fig 6: Locating Idle Speed Adjustment Screw (Q45)
G97F06561Courtesy of NISSAN MOTOR CO., U.S.A.
Fig 7: Identifying TP Switch Terminals (Q45)
G99B08860Courtesy of NISSAN MOTOR CO., U.S.A.
Fig 8: Checking Closed TP Switch Idle Position
G00010149Courtesy of NISSAN MOTOR CO., U.S.A.
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