Sentra 1.8L
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 - SENTRA 1.8L 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.
- Check the following:
- Harness connectors for improper connections.
- Wiring for improper connections, pinches and cuts.
- Air cleaner for clogging.
- Hoses and ducts for leaks.
Repair as necessary. Go to next step.
- Check Throttle Opener Operation
Check for clearance between throttle drum and throttle stop. See Fig 1. If clearance exists, go to step 4. If clearance does not exist, go to next step. - Check Throttle Opener Bolts
Check for loose throttle opener mounting bolts. Tighten bolts as necessary. If bolts are not loose, repair or replace throttle body as necessary. Go to next step. - Check Throttle Opener Operation
Start engine and let it idle. Inspect throttle opener rod. Throttle opener rod should move backward, and clearance should exist between throttle drum and throttle opener rod. See Fig 2. If operation is as specified, go to step 7. If operation is not as specified, go to next step. - Check Throttle Opener Vacuum Source
Disconnect vacuum hose from throttle opener. Check for vacuum at disconnected hose with engine running. If vacuum exists, repair or replace throttle body assembly as necessary. If vacuum does not exist, go to next step. - Check Vacuum Hose
Turn ignition off. Remove throttle opener vacuum hose. Check hose for blockage or leak. If vacuum hose is okay, clean vacuum port in throttle body with compressed air. If vacuum hose is not okay, replace vacuum hose. - Check Throttle Drum Operation
Ensure throttle is completely closed and throttle drum is contacting throttle stop. If throttle drum is contacting throttle stop, go to step 9. If throttle drum is not contacting throttle stop, go to next step. - Check Throttle Valve Operation
Ensure throttle cable is adjusted properly. Remove air intake ducts. Check throttle valve operation while moving throttle drum by hand. If throttle valve operation is okay, retighten throttle drum mounting nuts, then go to next step. If throttle valve operation is not okay, clean throttle body and throttle valve. - Check TP Switch Idle Position
Start engine and warm to normal operating temperature. Turn ignition off. Disconnect vacuum hose from throttle opener. Using a hand vacuum pump, apply vacuum to throttle opener until throttle opener rod is not contacting throttle drum. Disconnect TP switch harness connector. See Fig 3. Go to next step. - Insert a.002" (.05 mm) feeler gauge between throttle drum and throttle stop as shown in illustration. See Fig 4. Check continuity between TP switch terminals No. 5 and 6. See Figure. Continuity should exist. Remove.002" (.05 mm) feeler gauge, and insert.006" (.15 mm) feeler gauge. Continuity should not exist. If continuity is as specified, go to step 13. If continuity is not as specified, go to next step.
- Adjust TP Switch Idle Position
Loosen TP sensor mounting bolts. Remove.006" (.15 mm) feeler gauge, and insert.002" (.05 mm) feeler gauge. Ensure throttle opener rod is still not contacting throttle drum. Apply vacuum to throttle opener as necessary. Rotate TP sensor counterclockwise until continuity does not exist. Slowly rotate TP sensor clockwise until continuity exists, then tighten TP sensor mounting bolts. Go to next step. - Open and close throttle 2 or 3 times to ensure continuity exists when throttle is closed and does not exist when throttle is open. Remove.002" (.05 mm) feeler gauge, and insert.006" (.15 mm) feeler gauge. Open and close throttle 2 or 3 times to ensure continuity does not exist when throttle is closed. Go to next step.
- Reset TP Sensor Idle Position Memory
Remove feeler gauge. Ensure throttle opener rod is still not contacting throttle drum. Apply vacuum to throttle opener as necessary. Plug vacuum hose that was connected to throttle opener. Reconnect TP switch harness connector. Start engine and warm to normal operating temperature. Turn ignition off. Turn ignition on, wait at least 5 seconds, then turn ignition off and wait at least 10 seconds. Repeat 20 times. Go to next step. - Check For First Trip DTC
Turn ignition off. Remove vacuum pump from throttle opener, and reconnect vacuum hose. Start engine and warm to normal operating temperature. Increase engine speed to 2000-3000 RPM, then release throttle. Repeat 2 or 3 times. Using scan tool, check for first trip DTCs. If no first trip DTCs are present, go to next step. If any first trip DTCs are present, perform appropriate diagnostic procedure. See SELF-DIAGNOSTICS - SENTRA 1.8L article. - Check Target Idle Speed
Ensure engine is at normal operating temperature. Check idle speed. Target idle speed should be 600-700 RPM (M/T) or 750-850 RPM (A/T) with transmission in Park or Neutral. If idle speed is as specified, go to step 23. If idle speed is not as specified, go to next step. - Perform Idle Air Volume Learning
Perform idle air volume learning. See REMOVAL, OVERHAUL & INSTALLATION article. Go to next step. - Check Target Idle Speed Again
Ensure engine is at normal operating temperature. Check idle speed. Target idle speed should be 600-700 RPM (M/T) or 750-850 RPM (A/T) with transmission in Park or Neutral. If idle speed is as specified, go to step 21. If idle speed is not as specified, replace Idle Air Control Valve-Auxiliary Air Control (IACV-AAC) valve, then go to next step. - Perform Idle Air Volume Learning
Perform idle air volume learning. See REMOVAL, OVERHAUL & INSTALLATION article. Go to next step. - Check Target Idle Speed Again
Ensure engine is at normal operating temperature. Check idle speed. Target idle speed should be 600-700 RPM (M/T) or 750-850 RPM (A/T) with transmission in Park or Neutral. If idle speed is as specified, go to step 21. If idle speed is not as specified, go to next step. - Check ECM Function
Substitute a known good ECM to check ECM function. Perform initialization of Nissan Vehicle Immobilizer System (NVIS) system and registration of NVIS ignition key IDs. See appropriate IMMOBILIZER SYSTEMS article in ACCESSORIES & EQUIPMENT. Go to step 16. - Check Ignition Timing
Check ignition timing at idle using a timing light. Ignition timing should be 4-14 degrees BTDC with transmission in Park or Neutral. If ignition timing is as specified, go to step 31. If ignition timing is not as specified, go to next step. - Check Timing Chain Installation
Check timing chain installation. See appropriate article in ENGINES. If timing chain installation is okay, go to next step. If timing chain installation is not okay, repair as necessary, then go to step 16. - Check Ignition Timing
Check ignition timing at idle using a timing light. Ignition timing should be 4-14 degrees BTDC with transmission in Park or Neutral. If ignition timing is as specified, go to step 31. If ignition timing is not as specified, go to next step. - Perform Idle Air Volume Learning
Perform idle air volume learning. See REMOVAL, OVERHAUL & INSTALLATION article. Go to next step. - Check Target Idle Speed Again
Ensure engine is at normal operating temperature. Check idle speed. Target idle speed should be 600-700 RPM (M/T) or 750-850 RPM (A/T) with transmission in Park or Neutral. If idle speed is as specified, go to step 29. If idle speed is not as specified, replace IACV-AAC valve, then go to next step. - Perform Idle Air Volume Learning
Perform idle air volume learning. See REMOVAL, OVERHAUL & INSTALLATION article. Go to next step. - Check Target Idle Speed Again
Ensure engine is at normal operating temperature. Check idle speed. Target idle speed should be 600-700 RPM (M/T) or 750-850 RPM (A/T) with transmission in Park or Neutral. If idle speed is as specified, go to step 29. If idle speed is not as specified, go to next step. - Check ECM Function
Substitute a known good ECM to check ECM function. Perform initialization of Nissan Vehicle Immobilizer System (NVIS) system and registration of NVIS ignition key IDs. See appropriate IMMOBILIZER SYSTEMS article in ACCESSORIES & EQUIPMENT. Go to step 24. - Check Ignition Timing Again
Check ignition timing at idle using a timing light. Ignition timing should be 4-14 degrees BTDC with transmission in Park or Neutral. If ignition timing is as specified, go to step 31. If ignition timing is not as specified, go to next step. - Check Timing Chain Installation
Check timing chain installation. See appropriate article in ENGINES. If timing chain installation is okay, go to step 28. If timing chain installation is not okay, repair as necessary, then go to step 24. - Clear DTC Memory
DTCs may be stored in ECM and/or Transmission Control Module (TCM) from performing basic inspection. Clear DTCs from ECM and TCM. See SELF-DIAGNOSTICS - SENTRA 1.8L article.