Have you tried to perform an idle relearn procedure on your Nissan, but it won’t work? Any significant repair on your car may trigger issues with the engine’s idle speed. The ECU will detect this problem, throw a trouble code, and turn the check engine light on.
When this happens, you must perform a Nissan idle relearn procedure to restore the correct idle speed. This procedure helps the computer to learn the new changes and maintain the correct engine idle speed. If the idle relearn doesn’t restore your engine’s smooth idle, your car has issues you must fix.
I’ll take you through the causes of Nissan idle relearn not working and what to do. You’ll also learn what Nissan idle relearn means and how to perform the relearn procedure.
Question: What is Nissan Idle Relearn?
Idle relearn (throttle relearn) is a procedure to help the engine obtain its correct idle speed after a repair. Since your Nissan’s ECU controls some engine’s performances, this computer can lose communication with the repaired or replaced part.
Here are the instances that may require performing Nissan idle relearn:
- After disconnecting the battery
- Replacing the battery
- Replacing the Electronic Throttle Body (ETB)
- After cleaning the ETB
- After cleaning the Idle Air Control Valve (IACV)
Tampering with the battery is one of the most common reasons cars require an idle relearn. Remember that the ECU relies on your Nissan’s battery power to maintain the correct engine idle speed.
If you disconnect or replace the battery, the ECU will lose the information needed to maintain idle speed.
Another common reason your Nissan might require an idle relearn is after cleaning or replacing the ETB. The electronic throttle body control plays a significant role in maintaining the correct engine idle speed. Any changes to this component can destabilize the info your computer uses to balance idle speed.
So, how do you know that your Nissan requires an idle relearn? In most cases, your car will show symptoms like idling too low, high, or erratically. The check engine light will also turn on, and the ECU will throw related trouble codes. Sometimes, the engine may stall after stopping at a traffic light.
When you do an idle relearn, you recalibrate everything to ensure all components work together to maintain the correct engine idle speed.
Answer: Causes of Nissan Idle Relearn Not Working
If your Nissan idle speed won’t stabilize after conducting an idle relearn, several issues could be to blame.
Incorrect Idle Relearn Procedure
Failure to follow the correct steps for your Nissan idle relearn procedure can cause this problem. You may try repeating the procedure by closely following each step. But before conducting an idle relearn, ensure everything below checks out:
- Ensure the battery voltage is above 12.9 V when the engine is idle.
- Ensure your engine coolant temperature is between 158° and 212°F.
- Position your shift lever in Neutral or Park.
- Turn off the A/C, rear window defogger, and headlamp.
Before performing this procedure, you must have a stopwatch to ensure precise timing. Then follow these steps to do an idle relearn procedure:
Step 1: Position Learning Procedure With Accelerator Pedal Released
- Foot off the pedal
- Turn the key to the “ON” position. Wait for two seconds.
- Turn the key to the “OFF” position. Wait for 10 seconds.
- Repeat this process once.
Step 2: Position Learning Procedure With the Throttle Valve Closed
- Warm up the engine.
- Turn the engine off.
- Wait for 10 seconds.
- Foot off the accelerator pedal.
- Turn the key to the “ON” position. Wait for 10 seconds.
- Turn the key to the “ON” position. Wait for three seconds.
- Repeat this procedure five times.
- Press the pedal to the floor. Then release it.
- Press down the accelerator pedal five times within five seconds.
- Wait for seven seconds.
- Press and hold the pedal to the floor for approximately 20 seconds. You’ll see the blinking check engine light turn on steadily.
- Release the pedal.
- Start the engine. Then, allow it to idle.
After following each step, your Nissan’s engine should regain its idle speed. However, if the idle relearn won’t work, use an OBD-II scanner to check the stored trouble codes.
Below are other reasons for Nissan idle relearn not working:
Dirty Electronic Throttle Body
The electronic throttle body (ETB) can malfunction due to debris or dirt buildup. So, start by inspecting this component and clean it if necessary. A cleaning solution will help remove accumulated dirt and residue. After cleaning, use a paper towel or shop rag to wipe the dirt out of the throttle body.
Malfunctioning Idle Air Control Valve
The idle air control valve (IACV) controls your Nissan engine’s idling speed (RPM). Over time, this device can malfunction due to dirt or debris buildup or damage.
Use a carbon cleaner to remove any accumulated dirt or gunk. Then, use a clean cloth to wipe your IACV. You’ll need to replace the IACV if it looks damaged.
Battery Problems
Your Nissan’s battery must be appropriately charged and connected to ensure a successful idle relearn procedure. So, check the battery terminals to ensure they’re secure and clean.
If the battery looks okay, disconnect the negative terminal, wait at least 30 seconds, and reconnect it. Doing so will reset the ECU and allow the idle relearn to work. Check for low battery voltage if this fix doesn’t work. Recharge the battery or replace it if it fails to hold a charge.
Bad Throttle Position Sensor
The engine throttle position sensor (TPS) monitors the opening of the throttle valve and sends this info to the ECU. A bad TPS will trigger symptoms of idle relearn not working even after following each relearn step.
You can try resetting the TPS by disconnecting your Nissan’s battery for five minutes. If resetting doesn’t help, locate the TPS and inspect it for dirt or damage. Clean the sensor with a cleaning solvent to remove stuck dirt and grime. If the sensor fails after cleaning, consider a replacement.
Blown Fuse
Blown fuses are among the common reasons for electrical malfunctions in your Nissan. Your car has fuses for protecting the electronic throttle control systems (ETCs) and the alternator. These fuses must function properly to allow electricity flow to the ETCs and the alternator.
If your car has a blown ETCs or alternator fuse, the idle relearn won’t work even after following the correct procedure. So, open the fuse box and check for any blown fuse.
Wrapping Up
Nissan idle relearn not working may stem from issues with the throttle body, idle air control valve, battery, throttle position sensor, or fuses. Before you diagnose the root cause, ensure you’ve performed the correct Nissan idle relearn procedure.
If the problem persists, check for the above issues and fix them. You may also take your Nissan to the dealership or an authorized mechanic to diagnose and fix the root problem.