I’ve found some TSB with the manual procedure for learing. But it’s for 2.0 petrol engine. I’m thinking it’s the same for my engine as well:
“Perform the throttle valve position learning and idling engine rpm inspection.
a. Connect the M-MDS.
b. Turn the ignition to ON without starting the engine for one minute, then turn it to OFF.
c. After one minute has passed, start the engine.
d. Warm up the engine at idling until the cooling fan starts operating or until the coolant temperature
reaches 194 °F (90 °C) or higher.
e. Turn off any electrical load, including the A/C, with the shifter in Neutral or Park position.
f. Let the engine run for five minutes.
g. Measure the engine rpm at idle using the M-MDS to confirm it is within specification according to the Workshop Manual.
I will give it a try.