Relearn the Idle Air Volume Without a Scan Tool

After the throttle body is cleaned, or the battery or engine control module is disconnected, a Nissan Sentra (B17, 2013–2019) with the MRA8DE 1.8-litre engine can idle rough, hunt or stall until the ECM relearns its idle settings. The factory way to do this without a scan tool is a precise pedal-and-ignition routine in three parts: accelerator-pedal released-position learning, throttle-valve closed-position learning, then idle air volume learning.

Conditions First (the Relearn Cancels If Any Is Missed)

• Battery voltage above about 12.9 V at idle.
• Engine at normal operating temperature.
• Selector in P or N (CVT) or in neutral (manual), steering straight ahead, car stopped.
• All electrical loads OFF — air conditioning, headlights and rear defogger.
• Transmission warmed up — drive about 10 minutes first.

Part A — Accelerator Pedal Released-Position Learning

1. Make sure the accelerator pedal is fully released.
2. Turn the ignition ON (engine off) and wait at least 2 seconds.
3. Turn the ignition OFF and wait at least 10 seconds.
4. Turn the ignition ON again and wait at least 2 seconds.
5. Turn the ignition OFF and wait at least 10 seconds.

Part B — Throttle-Valve Closed-Position Learning

1. Start the engine and let it warm up.
2. Turn the ignition OFF and wait at least 10 seconds — during this time you should hear the throttle valve move.

Part C — Idle Air Volume Learning (No Scan Tool)

Count the seconds accurately — use a watch or phone timer.

1. With Parts A and B done, start the engine and warm it to normal operating temperature.
2. Turn the ignition OFF and wait at least 10 seconds.
3. Confirm the accelerator is fully released, turn the ignition ON and wait exactly 3 seconds.
4. Within the next 5 seconds, fully depress and fully release the accelerator pedal five times, quickly.
5. Wait 7 seconds, then fully depress the pedal and hold it for about 20 seconds until the check-engine (MIL) light stops blinking and stays ON.
6. Within 3 seconds of the light going steady, fully release the pedal.
7. Start the engine and let it idle.
8. Wait 20 seconds, then rev the engine two or three times and confirm the idle is now smooth.

If it does not take, recheck every condition above and repeat from Part A.

Frequently Asked Questions

Do I really not need a scan tool? Correct — this is the factory “without CONSULT” method using only the pedal and ignition. A scan tool can do it faster but is not required.

My idle went rough after cleaning the throttle body — is this the fix? Yes. A throttle-body clean or a battery disconnect is exactly what calls for this relearn.

The check-engine light blinks during step 5 — is that a fault? No. The light blinking and then going steady is the signal that the learn is running; it is expected here.

Does this work on the 1.6 turbo (SR Turbo / NISMO)? The MR16DDT uses the same style of relearn, but the exact timing can differ slightly — the sequence above is for the MRA8DE 1.8.

If the check-engine light is on and you want to read the underlying trouble code first, visit our sister site autodtcs.com.