Lord Ahmed sent the message about two minutes before ploughing into a car that had already crashed.
Ahmed pleaded guilty to dangerous driving after a police investigation revealed that he had sent and received a string of text messages as he drove on the motorway.
Sheffield Magistrates' Court was told that Ahmed was driving his Jaguar from Dewsbury, West Yorkshire, to his home in Rotherham, South Yorkshire, with his wife and mother. David Scutt, for the prosecution, said that Ahmed exchanged at least five messages with a journalist as he drove from Junction 40 to Junction 35, where the accident happened.
Mr Scutt said that although texting while driving was an offence, the use of the telephone had no bearing on the collision that killed Mr Gombar, a Slovak, from Leigh, Lancashire.
Police carried out a detailed investigation, including plotting the text messages by mobile phone transmitters, the court was told.
Mr Scutt said that the messages were sent as Ahmed drove at about 60mph and the final message was sent one to two miles before the impact.
The peer was knocked out by the impact and suffered facial injuries. When he came round he dialled 999 from the same mobile phone. Mr Scutt said: "The defendant used his mobile phone to send and receive a series of text messages while driving on the motorway along a 17-mile stretch before the accident. It was prolonged and deliberate use.
"But there is no evidence to prove that the defendant's use of a mobile phone caused the accident."
District Judge Mark Hadfield adjourned the case for presentence reports and said that he would consider all sentencing options. He ordered that Ahmed be given an interim driving ban.
