How to perform a Honda throttle body relearn

Perform a Honda throttle body relearn without a scan tool

Any time you disconnect the battery on your Honda or clean its electronic

Honda electronic throttle body

throttle body, you must perform a Honda throttle body relearn afterward. Honda calls it an idle learn procedure.

The shop manual says you need a scan tool to do this, but you don’t.

How to perform a Honda idle learn procedure procedure

1) Turn off ALL electrical loads. No lights, blower, AC, etc. Nothing on.
2) Start engine and let it idle until the radiator cooling fan comes on. Then continue to let it idle for a full 10-mins.
During that time the ECM will recalculate throttle plate position.
3) Done

What the throttle body relearn procedure does

There is not idle air bypass on an electronic throttle body. All the air needed for idling comes directly through the throttle plate. Over time, the bore of the throttle body can accumulate carbon buildup, thereby reducing air flow. The ECM senses the lower airflow and commands the throttle body to open wider to allow more air in.

If you disconnect the battery the ECM will lose is “adaptive memory” and you’ll have trouble starting the engine because the computer is letting in too much air. The same thing happens if you clean the carbon buildup from the throttle body. That’s why you must perform the relearn procedure after cleaning or any time you disconnect the battery.

©, 2022 Rick Muscoplat