I've been deep through these forums and cannot find a single occurrence similar to mine....

Batt and Alt test good. M and S only come on when driving over 75 MPH and in 70+ degree heat background info below.

We took our Discovery to Florida from Wisconsin this last week and shortly after we passed Nashville the M and S lights were blinking along with the D indicator shutting off. Pulled off the highway and shut it down. Started googling possible causes. Found Lot's of Power (batt+alt) issues, gear selector switch... so started the truck up to see if it's battery issue and it started up perfectly, went into gear and acted like normal. No more M and S lights, but Service engine soon was still there - luckily orielys was 1.5 miles from the exit I pulled off from, so went there to read codes. From the highway to oriely I got it up to 55 MPH with no fault lights coming back on. Still had it checked. P0705 came up Transmission Range Sensor Circuit Malfunction. Also had batt and Alt tested - came back with good results. Everything seemed ok, brushed it off as a one time freak failure. Got back on the highway for about 150-200 miles, steady at 75 the lights came on flashing again. Pulled over at nearest exit - checked all fluids and everything was fine. thought maybe it was getting too hot so we decided to eat and let it rest. got back on highway after an hour and got a good 200 miles before lights came on again. Pulled over - restarted it and kept the speed at 70 from Atlanta to St. Petersburg Florida (400+ miles) and the lights did not come on again. Shifting and everything else felt normal the entire time.

Arrived in St. Petersburg on Wednesday 3/29 and tried to schedule service at land rover dealership and other import places. No one had availability for the next week. Decided to keep driving it around town and on the way back keep it at 70 (made for a long drive time). No lights flashing unless i slipped and let it get going too fast (75+). On our straight 24 hour drive home, after we got north enough to where the weather was around 50 degrees or less - I just happened to notice that I was going 80. decided to let ride it out and see if the problem returned - lo and behold it did NOT return. from that point on - just north of Nashville, we drove back to Wisconsin (avg. 80 MPH) without having any other lights come on.

Does anyone have an idea what I should looking at? or have seen this before and know what was done to fix the problem? For now, it's running like normal and For the next month or so, we should be OK on temp in Wisconsin but dont want to run into any issues in Summer. But I want to fix the problem before it leads to something else.