4WD and LOCK error message

[bongofury]

Hi. Have an error message while using 4WD accompanied by the drive setting flashing between 4WD and LOCK. No problem in 2WD. Nothing conclusive following OBD scans, but talking to someone at a Mitsubishi garage here in the UK was suggested it could be a transfer switch failure (the same error message on an Outlander for that particular fault apparently), though they couldn't offer me a slot to take a look for a month (accompanied by the usual disclaimer that as a grey import they couldn't promise their software would work, etc., etc.). Anyone else had this problem and resolved it? Or alternative thoughts on what it might be? It's not an ABS sensor as they've all been checkd and passed. Thanks v much