Montero Sport XLS 4WD V6-3.0L SOHC (1999)
STEP 6.
Check harness connector C-50 at the ECM <M/T>/C-69 at the PCM <A/T> for damage.
If harness connector C-50 <M/T>/C-89 <A/T> is damaged, repair or replace it.
If harness connector C-50 <M/T>/C-89 <A/T> is in good condition, replace the ECM <M/T>/PCM <A/T>.
Then confirm that the malfunction symptom is eliminated.