Idle Relearn - FX35, I35, M35, G35, G37, 350z, 370z, Maxima, Murano, Sentra, Altima, M45, M56,

Introduction

This tutorial provides a step-by-step guide to performing an idle relearn procedure for various Nissan and Infiniti models, including the G35, 350Z, and Altima. The purpose is to reset the throttle body and ensure the engine idles at the OEM specification of 650 RPM. This is particularly important if you've experienced issues like high idle or engine codes such as P0507 and P2102.

Step 1: Prepare the Vehicle

Before you begin the idle relearn, ensure the following conditions are met:

• Battery voltage is above 12.9V (at idle).
• Engine coolant temperature is between 70 - 100°C (158 - 212°F).
• Park/Neutral Position (PNP) switch is ON (shifter in Park or Neutral).
• Electric load switch is OFF (turn off air conditioning, headlights, and rear defogger).
• Steering wheel is in a neutral position (straight-ahead).
• Vehicle speed is stopped.
• Transmission is warmed up (drive for at least 10 minutes).

Step 2: Perform Accelerator Pedal Release Position Learning

1. Ensure the accelerator pedal is fully released.
2. Turn the ignition switch to the ON position and wait for at least 2 seconds.
3. Turn the ignition switch OFF and wait at least 10 seconds.
4. Repeat turning the ignition ON and OFF (waiting the same intervals) once more.

Step 3: Perform Throttle Valve Closed Position Learning

1. Make sure the accelerator pedal is fully released.
2. Turn the ignition switch to the ON position.
3. Turn the ignition switch OFF and wait for 10 seconds. You should hear the throttle valve moving during this time.

Step 4: Start Idle Air Volume Learning

1. Start the engine and let it warm up to normal operating temperature.
2. Turn the ignition switch OFF and wait for at least 10 seconds.
3. Confirm the accelerator pedal is fully released, then turn the ignition switch to ON and wait for 3 seconds.
4. Quickly repeat the following steps five times within 5 seconds:
   • Fully depress the accelerator pedal HARD.
   • Fully release the accelerator pedal.
5. Wait 7 seconds, then fully depress the accelerator pedal and hold it for approximately 20 seconds until the Check Engine Light (CEL) stops blinking and turns solid.
6. Fully release the accelerator pedal within 3 seconds after the CEL is ON.
7. Start the engine and let it idle for 20 seconds.
8. Rev the engine two or three times to ensure the idle speed and ignition timing are within specifications.

Step 5: Troubleshooting Check Engine Light

• If the CEL remains ON after performing the above steps, repeat the entire process as timing is critical for resetting the ECU.
• Ensure to follow the steps accurately and confirm that all conditions were satisfied before starting the procedure.

Conclusion

You have successfully performed the idle relearn procedure. This process is essential to ensure your vehicle's throttle body is functioning correctly and the engine idles at the correct RPM. If you encounter persistent issues, consider checking for other underlying problems or consult a professional mechanic. Feel free to revisit this guide anytime your vehicle experiences idle issues or after servicing the throttle body.