M and s lights advice.

After having my td5 disco a month now yesterday my little brother decided he wanted one so travelled 200 miles and came back with an 03 plate td5 auto with only 72k on the clock which is nicer than mine😡.
However when he was about 20 miles from home the m and s lights came on!!
He pulled over, switch the disco off and on and they went out again. He's just text me and said the same thing happened today after driving it for a while( cured by switching off and on).
Can someone give me some advice as why this is happening???. Disco seems to drive normally when m and s lights are on( think they were flashing as well).
Cheers.

Had a look at my brothers disco and there is oil in the ecu plug. Engine runs fine still but would this cause the m and s lights to come on or does gearbox have seperate ecu?

the transmission has it's own ECU ... the only straight way to find the fault without guessing around is to plug in a tester