An image of a Honda Fit in a service bay (AI generated)

Honda Idle Learn: How To Memorize After Learning

This page started as an internal memo, but I figured I may as well share it for anyone else out there who is having a rough time trying to get a Honda idle learn to complete. The TL;DR version is that starting around 2012, Honda vehicles require you to “save” after performing the idle learn by jumping the SCS connector for 60 seconds with the key off.

What has changed about Honda idle learn

Idle learn for Honda vehicles has been necessary for quite a while now. With older Honda vehicles, that involved idling the car for a specified period of time. Newer Honda vehicles are different. They require connecting the SCS connector with the vehicle off to memorize the idle learn or letting the car sit key off for enough time.

When Does This Start?

This change starts in the mid-2010s. For the Honda Accord it started in 2013. For the Honda Fit it started in 2015. The easiest way to check is to search “idle learn” on the Honda SIS website. Choose either “PCM Idle Learn Procedure” or “ECM Idle Learn Procedure”. 

When is idle learning required?

For this Fit, Honda requires idle learning after:

  • PCM replacement, reset, or software update.
  • Throttle body replacement or cleaning.
  • Any other work that might affect the idle speed

Perform the learn after the software update, even if it was already performed earlier in the repair. Clearing trouble codes with HDS alone does not require another idle learn on this model. Honda idle-learn instructions, reproduced

Learning and saving are separate steps

The PCM learns the engine’s idle characteristics while the engine runs under the required conditions. Honda states that the learning status is memorized after an hour with the ignition off. The SCS procedure allows that information to be saved quickly, without waiting through the normal key-off period.

Activating SCS after key-off and waiting 60 seconds finalizes storage of the learned information. This is what we mean by “locking the learn into memory.” It does not replace the engine-running portion of the procedure. Honda learning and memory-storage instructions

It may be that the “natural” idle learn will only be memorized on the key off cycle immediately following a running cycle that meets the idle learn criteria. For example, you might idle the car for 5 minutes with no load, turn the car off, but then start the car to park it. In this case the learn might not complete because the learn criteria weren’t met on the trip to the parking space. The learn will probably eventually complete on its own with normal driving, but the car shouldn’t be shipped in an unfinished state. 

Use the SCS control on the HDS main screen

The SCS control is available in several locations on the HDS, but for key-off use, you must use the SCS control on the main screen before connecting to any of the control units (including the ECM). Using the SCS control from live data, for example, will cause the scanner to lose connection and the memorization will fail.

Navigate to the main screen first, but activate SCS only after switching the ignition off.

Idle-learn procedure

  1. Switch off electrical loads, including the A/C, audio system, lights, and rear defogger.
  2. Navigate to the ECM (PGM-FI) with the HDS. Reset the PCM with the key on/engine off
  3. Turn the ignition OFF
  4. Switch the ignition ON and wait two seconds.
  5. Start the engine. With the CVT in P or N, or a manual transmission in neutral, hold approximately 3,000 rpm without load until the radiator fan operates or coolant temperature reaches 194°F/90°C.
  6. Release the accelerator and allow the engine to idle for approximately five minutes. Keep electrical loads off. Exclude any time the radiator fan runs from the five-minute period.
  7. Leave the diagnostic interface connected, exit the PGM-FI session, and return to the HDS main screen.
  8. Switch the ignition OFF/LOCK.
  9. From the HDS main screen, activate the SCS jumper function.
  10. Wait 60 seconds with the ignition off.
  11. Exit SCS mode.

Verify completion before release

Switch the ignition on, reconnect to PGM-FI, and check the idle-learn status. Confirm that “Idle learn (air learn)” reports complete; a completed torque-learn flag alone does not confirm air-learn completion. Record the result on the repair order.