Hey guys! Ever found your 2009 Nissan Murano idling a little rough, or maybe even stalling after you've cleaned the throttle body or disconnected the battery? Chances are, you need to perform an idle relearn procedure. Don't worry; it sounds more complicated than it is. This guide will walk you through the steps to get your Murano purring like a kitten again. So, let's dive in and get that idle smooth as silk!

Why Perform an Idle Relearn?

Before we jump into the how-to, let's understand why this procedure is even necessary. Your Murano's engine control unit (ECU) is a smart cookie. It learns and adapts to your driving style and the engine's condition over time. One of the things it learns is the ideal idle speed. When you clean the throttle body, disconnect the battery, or replace certain engine components, you're essentially wiping out the ECU's memory of that learned idle. This can cause the engine to idle too low, too high, or erratically.

The idle relearn procedure is like giving the ECU a refresher course. It teaches the computer the correct parameters for idling, ensuring smooth and efficient operation. Without it, you might experience issues like:

• Rough idling
• Stalling, especially when coming to a stop
• Poor fuel economy
• Hesitation during acceleration

Think of it as re-calibrating your engine's brain! Now that we know why it's important, let's get down to the nitty-gritty.

Prerequisites

Before you even think about starting the idle relearn, make sure you've got these prerequisites covered. This will save you a ton of frustration down the line. Trust me, skipping these steps is like trying to bake a cake without preheating the oven – it just won't turn out right!

1. No Diagnostic Trouble Codes (DTCs): This is crucial. If your check engine light is on, address those problems first. The idle relearn won't work properly if the ECU is already dealing with other issues. Use an OBD-II scanner to check for any codes and resolve them before proceeding. Think of it like this: you wouldn't try to teach someone algebra if they didn't know basic arithmetic, right?
2. Engine at Operating Temperature: The engine needs to be warmed up. A cold engine won't give the ECU the correct readings. Drive the car for at least 10-15 minutes to get it up to normal operating temperature. Keep an eye on your temperature gauge – you want it right in the middle.
3. All Electrical Loads Off: Turn off everything that draws power: headlights, air conditioning, radio, rear defogger, etc. These electrical loads can interfere with the relearn process. The ECU needs to focus solely on the idle. It's like trying to concentrate on a test with a bunch of distractions around you – not gonna happen!
4. Steering Wheel Centered: Ensure the steering wheel is in the center position. This might seem odd, but some Nissan systems are sensitive to steering angle during the relearn. Just center it to be safe.
5. Transmission in Park (Automatic) or Neutral (Manual): Make sure your car is safely parked or in neutral with the parking brake engaged. Safety first, always!

The Idle Relearn Procedure: Step-by-Step

Alright, with the prerequisites out of the way, let's get to the main event. This procedure can be a bit finicky, so pay close attention and follow the steps exactly. Patience is key here, guys! If it doesn't work the first time, don't get discouraged – just try again.

1. Turn the Ignition On (But Don't Start the Engine): Insert your key and turn it to the "ON" position, but do not start the engine. Leave it in this position for exactly three seconds. This allows the ECU to power up and prepare for the relearn.
2. Press and Release the Accelerator Pedal Five Times: Within five seconds of turning the ignition on, fully depress the accelerator pedal and then release it five times in quick succession. Make sure you're pressing it all the way to the floor each time. This is like sending a signal to the ECU that you're ready to start the relearn process.
3. Wait Seven Seconds: After the fifth press, release the pedal and wait exactly seven seconds. Do not touch the accelerator pedal during this time. The ECU is now processing the signal and preparing for the next step.
4. Fully Depress the Accelerator Pedal and Hold: After the seven seconds, fully depress the accelerator pedal and hold it down. Do not release it.
5. Wait for the Check Engine Light to Flash: Keep holding the accelerator pedal down. After about 10 seconds, the check engine light should start to flash. This indicates that the ECU has entered the idle relearn mode. If the check engine light doesn't flash after 10 seconds, something went wrong, and you'll need to start the process over from step one.
6. Release the Accelerator Pedal: Once the check engine light starts flashing, immediately release the accelerator pedal.
7. Start the Engine: Now, start the engine. Do not touch the accelerator pedal. Let the engine idle.
8. Observe the Idle Speed: Let the engine idle for at least 20 seconds. The ECU is now learning the correct idle speed. The idle speed may fluctuate during this time, but it should eventually settle down to a smooth and stable RPM.
9. If the Idle is Still Rough: If the idle is still rough or unstable after 20 seconds, let the engine run for a few more minutes. The ECU may need more time to learn the correct parameters. If it still doesn't improve after a few minutes, turn off the engine and repeat the entire procedure from step one.

Troubleshooting

Sometimes, even if you follow the steps perfectly, the idle relearn just doesn't seem to work. Here are some common issues and how to troubleshoot them:

• Check Engine Light Doesn't Flash: If the check engine light doesn't flash after step five, it usually means you didn't perform the accelerator pedal presses correctly or the timing was off. Make sure you're pressing the pedal fully and that you're following the timing exactly. Try the procedure again, paying close attention to the timing.
• Idle Remains Rough: If the idle remains rough after the procedure, double-check that you've met all the prerequisites. Make sure there are no DTCs, the engine is at operating temperature, and all electrical loads are off. Also, make sure the throttle body is clean. A dirty throttle body can prevent the ECU from learning the correct idle.
• OBD-II Scanner to the Rescue: Some higher-end OBD-II scanners have a built-in idle relearn function. If you're having trouble with the manual procedure, you can try using a scanner to perform the relearn. This can sometimes be more reliable than the manual method.

When to Seek Professional Help

If you've tried the idle relearn procedure multiple times and you're still having problems, it might be time to seek professional help. There could be other underlying issues causing the rough idle, such as a vacuum leak, a faulty mass airflow sensor, or a problem with the fuel injectors. A qualified mechanic can diagnose the problem and recommend the appropriate repairs.

Final Thoughts

Performing an idle relearn on your 2009 Nissan Murano might seem daunting at first, but with a little patience and attention to detail, you can definitely do it yourself. Just remember to follow the steps carefully, meet all the prerequisites, and don't be afraid to try again if it doesn't work the first time. And if all else fails, there's always a friendly mechanic nearby to lend a hand. Good luck, and happy motoring!