Have a 2007 TRX400AT that bogs down and won't run in auto mode but runs perfect in ES mode. ECM will not put out any error codes so I am at a loss and all the Honda dealers in the area are crooks. Any help would be appreciated.

 

Strange that it goes into emergency mode but doesn't fetch up a fault code, could indicate a fault in the ECU. Frankly this is going to be difficult to diagnose. Normally if a sensor gives the wrong information, but is not totally dead, you can get it not changing when it should, etc, without fault codes, because the ECU doesn't know anything is wrong, but this seems like it knows there is something wrong but doesn't tell you what. You could try getting the workshop manual, this has a fault diagnosis chart.

 

Wont run? Do you mean engine goes dead in auto? or Atv wont pull or go in auto?Sorry for the questions just trying to understand whats going on..Can you give us some history on atv like you just traded for an was doing this or you had atv for awhile an slowly getting worse,have you changed any parts ?